├── .idea ├── .name ├── copyright │ └── profiles_settings.xml ├── encodings.xml ├── modules.xml ├── runConfigurations.xml ├── compiler.xml ├── gradle.xml └── misc.xml ├── app ├── .gitignore ├── src │ ├── main │ │ ├── res │ │ │ ├── values │ │ │ │ ├── strings.xml │ │ │ │ ├── colors.xml │ │ │ │ ├── dimens.xml │ │ │ │ └── styles.xml │ │ │ ├── mipmap-hdpi │ │ │ │ └── ic_launcher.png │ │ │ ├── mipmap-mdpi │ │ │ │ └── ic_launcher.png │ │ │ ├── mipmap-xhdpi │ │ │ │ └── ic_launcher.png │ │ │ ├── mipmap-xxhdpi │ │ │ │ └── ic_launcher.png │ │ │ ├── mipmap-xxxhdpi │ │ │ │ └── ic_launcher.png │ │ │ ├── values-w820dp │ │ │ │ └── dimens.xml │ │ │ └── layout │ │ │ │ └── activity_main.xml │ │ ├── java │ │ │ └── com │ │ │ │ └── fashare │ │ │ │ └── hellokotlin │ │ │ │ └── MainActivity.java │ │ ├── kotlin │ │ │ └── com │ │ │ │ └── fashare │ │ │ │ └── hellokotlin │ │ │ │ ├── feature │ │ │ │ ├── delegate │ │ │ │ │ └── Delegate.kt │ │ │ │ └── extension │ │ │ │ │ └── Extension.kt │ │ │ │ └── sugar │ │ │ │ ├── classes │ │ │ │ └── SomeClasses.kt │ │ │ │ ├── stream │ │ │ │ └── StreamLikeJava8.kt │ │ │ │ ├── interfaces │ │ │ │ └── DefaultInterface.kt │ │ │ │ ├── safe │ │ │ │ └── NullPointerSafe.kt │ │ │ │ └── lambda │ │ │ │ └── LambdaTest.kt │ │ └── AndroidManifest.xml │ ├── test │ │ └── java │ │ │ └── com │ │ │ └── fashare │ │ │ └── hellokotlin │ │ │ └── ExampleUnitTest.java │ └── androidTest │ │ └── java │ │ └── com │ │ └── fashare │ │ └── hellokotlin │ │ └── ApplicationTest.java ├── proguard-rules.pro └── build.gradle ├── mydemo ├── .gitignore ├── src │ ├── main │ │ ├── res │ │ │ ├── values │ │ │ │ ├── strings.xml │ │ │ │ ├── dimens.xml │ │ │ │ ├── colors.xml │ │ │ │ └── styles.xml │ │ │ ├── drawable │ │ │ │ └── ic_launcher.png │ │ │ ├── values-w820dp │ │ │ │ └── dimens.xml │ │ │ └── layout │ │ │ │ ├── activity_main.xml │ │ │ │ └── item_story.xml │ │ ├── kotlin │ │ │ └── com │ │ │ │ └── fashare │ │ │ │ └── mydemo │ │ │ │ ├── Api.kt │ │ │ │ ├── data │ │ │ │ └── HomeInfo.kt │ │ │ │ └── MainActivity.kt │ │ └── AndroidManifest.xml │ ├── test │ │ └── java │ │ │ └── com │ │ │ └── fashare │ │ │ └── mydemo │ │ │ └── ExampleUnitTest.java │ └── androidTest │ │ └── java │ │ └── com │ │ └── fashare │ │ └── mydemo │ │ └── ApplicationTest.java ├── proguard-rules.pro └── build.gradle ├── settings.gradle ├── screen-record ├── mydemo.jpg └── project.png ├── gradle └── wrapper │ ├── gradle-wrapper.jar │ └── gradle-wrapper.properties ├── .gitignore ├── gradle.properties ├── gradlew.bat ├── gradlew └── README.md /.idea/.name: -------------------------------------------------------------------------------- 1 | HelloKotlin -------------------------------------------------------------------------------- /app/.gitignore: -------------------------------------------------------------------------------- 1 | /build 2 | -------------------------------------------------------------------------------- /mydemo/.gitignore: -------------------------------------------------------------------------------- 1 | /build 2 | -------------------------------------------------------------------------------- /settings.gradle: -------------------------------------------------------------------------------- 1 | include ':app', ':mydemo' 2 | -------------------------------------------------------------------------------- /screen-record/mydemo.jpg: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/screen-record/mydemo.jpg -------------------------------------------------------------------------------- /screen-record/project.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/screen-record/project.png -------------------------------------------------------------------------------- /.idea/copyright/profiles_settings.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | -------------------------------------------------------------------------------- /app/src/main/res/values/strings.xml: -------------------------------------------------------------------------------- 1 | 2 | HelloKotlin 3 | 4 | -------------------------------------------------------------------------------- /mydemo/src/main/res/values/strings.xml: -------------------------------------------------------------------------------- 1 | 2 | MyDemo 3 | 4 | -------------------------------------------------------------------------------- /gradle/wrapper/gradle-wrapper.jar: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/gradle/wrapper/gradle-wrapper.jar -------------------------------------------------------------------------------- /app/src/main/res/mipmap-hdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/app/src/main/res/mipmap-hdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-mdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/app/src/main/res/mipmap-mdpi/ic_launcher.png -------------------------------------------------------------------------------- /mydemo/src/main/res/drawable/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/mydemo/src/main/res/drawable/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-xhdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/app/src/main/res/mipmap-xhdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-xxhdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/app/src/main/res/mipmap-xxhdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-xxxhdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/fashare2015/HelloKotlin/HEAD/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | *.iml 2 | .gradle 3 | /local.properties 4 | /.idea/workspace.xml 5 | /.idea/libraries 6 | /.idea/* 7 | .DS_Store 8 | /build 9 | /captures 10 | -------------------------------------------------------------------------------- /.idea/encodings.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | -------------------------------------------------------------------------------- /app/src/main/res/values/colors.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | #3F51B5 4 | #303F9F 5 | #FF4081 6 | 7 | -------------------------------------------------------------------------------- /app/src/main/res/values/dimens.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 16dp 4 | 16dp 5 | 6 | -------------------------------------------------------------------------------- /mydemo/src/main/res/values/dimens.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 16dp 4 | 16dp 5 | 6 | -------------------------------------------------------------------------------- /mydemo/src/main/res/values/colors.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | #3F51B5 4 | #303F9F 5 | #FF4081 6 | 7 | -------------------------------------------------------------------------------- /gradle/wrapper/gradle-wrapper.properties: -------------------------------------------------------------------------------- 1 | #Mon Dec 28 10:00:20 PST 2015 2 | distributionBase=GRADLE_USER_HOME 3 | distributionPath=wrapper/dists 4 | zipStoreBase=GRADLE_USER_HOME 5 | zipStorePath=wrapper/dists 6 | distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-all.zip 7 | -------------------------------------------------------------------------------- /app/src/main/res/values-w820dp/dimens.xml: -------------------------------------------------------------------------------- 1 | 2 | 5 | 64dp 6 | 7 | -------------------------------------------------------------------------------- /mydemo/src/main/res/values-w820dp/dimens.xml: -------------------------------------------------------------------------------- 1 | 2 | 5 | 64dp 6 | 7 | -------------------------------------------------------------------------------- /mydemo/src/test/java/com/fashare/mydemo/ExampleUnitTest.java: -------------------------------------------------------------------------------- 1 | package com.fashare.mydemo; 2 | 3 | import org.junit.Test; 4 | 5 | import static org.junit.Assert.*; 6 | 7 | /** 8 | * To work on unit tests, switch the Test Artifact in the Build Variants view. 9 | */ 10 | public class ExampleUnitTest { 11 | @Test 12 | public void addition_isCorrect() throws Exception { 13 | assertEquals(4, 2 + 2); 14 | } 15 | } -------------------------------------------------------------------------------- /app/src/test/java/com/fashare/hellokotlin/ExampleUnitTest.java: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin; 2 | 3 | import org.junit.Test; 4 | 5 | import static org.junit.Assert.*; 6 | 7 | /** 8 | * To work on unit tests, switch the Test Artifact in the Build Variants view. 9 | */ 10 | public class ExampleUnitTest { 11 | @Test 12 | public void addition_isCorrect() throws Exception { 13 | assertEquals(4, 2 + 2); 14 | } 15 | } -------------------------------------------------------------------------------- /mydemo/src/main/kotlin/com/fashare/mydemo/Api.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.mydemo 2 | 3 | import com.fashare.mydemo.data.HomeInfo 4 | import retrofit2.http.GET 5 | import rx.Observable 6 | 7 | /** 8 | * Created by apple on 17-5-31. 9 | */ 10 | interface Api { 11 | companion object{ 12 | val BASE_URL: String = "http://news-at.zhihu.com/" 13 | } 14 | 15 | @GET("api/4/news/latest") 16 | fun getHomeInfo(): Observable 17 | } -------------------------------------------------------------------------------- /app/src/main/java/com/fashare/hellokotlin/MainActivity.java: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin; 2 | 3 | import android.support.v7.app.AppCompatActivity; 4 | import android.os.Bundle; 5 | 6 | public class MainActivity extends AppCompatActivity { 7 | 8 | @Override 9 | protected void onCreate(Bundle savedInstanceState) { 10 | super.onCreate(savedInstanceState); 11 | setContentView(R.layout.activity_main); 12 | 13 | 14 | } 15 | } 16 | -------------------------------------------------------------------------------- /app/src/main/res/values/styles.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 10 | 11 | 12 | -------------------------------------------------------------------------------- /mydemo/src/androidTest/java/com/fashare/mydemo/ApplicationTest.java: -------------------------------------------------------------------------------- 1 | package com.fashare.mydemo; 2 | 3 | import android.app.Application; 4 | import android.test.ApplicationTestCase; 5 | 6 | /** 7 | * Testing Fundamentals 8 | */ 9 | public class ApplicationTest extends ApplicationTestCase { 10 | public ApplicationTest() { 11 | super(Application.class); 12 | } 13 | } -------------------------------------------------------------------------------- /mydemo/src/main/res/values/styles.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 10 | 11 | 12 | -------------------------------------------------------------------------------- /app/src/androidTest/java/com/fashare/hellokotlin/ApplicationTest.java: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin; 2 | 3 | import android.app.Application; 4 | import android.test.ApplicationTestCase; 5 | 6 | /** 7 | * Testing Fundamentals 8 | */ 9 | public class ApplicationTest extends ApplicationTestCase { 10 | public ApplicationTest() { 11 | super(Application.class); 12 | } 13 | } -------------------------------------------------------------------------------- /.idea/modules.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/feature/delegate/Delegate.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.feature.delegate 2 | 3 | 4 | /** 5 | * Created by apple on 17-5-31. 6 | * 7 | * 属性代理 8 | */ 9 | 10 | val lazySum: Int by lazy { 11 | println("begin compute lazySum ...") 12 | var sum = 0 13 | for (i in 0..100) 14 | sum += i 15 | println("lazySum computed!\n") 16 | sum // 返回计算结果 17 | } 18 | 19 | fun main(args: Array) { 20 | println(lazySum) 21 | println(lazySum) 22 | } -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/sugar/classes/SomeClasses.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.sugar.classes 2 | 3 | /** 4 | * Created by apple on 17-5-31. 5 | * 类与继承 6 | */ 7 | open class People(val name: String){} 8 | 9 | class Coder(name: String, val language: String = "Kotlin"): People(name){ 10 | 11 | override fun toString(): String { 12 | return "name: $name, language: $language" 13 | } 14 | } 15 | 16 | fun main(args: Array) { 17 | val coder = Coder("Tom") 18 | 19 | println(coder) 20 | } -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/sugar/stream/StreamLikeJava8.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.sugar.stream 2 | 3 | /** 4 | * Created by apple on 17-5-30. 5 | * 6 | * 集合操作, 类似于 Java8 新增的 Stream 7 | */ 8 | fun main(args: Array){ 9 | val list = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) 10 | list.filter { it%2==0 } // 取偶数 11 | .map{ it*it } // 平方 12 | .sortedDescending() // 降序排序 13 | .take(3) // 取前 3 个 14 | .forEach { println(it) } // 遍历, 打印 15 | } -------------------------------------------------------------------------------- /.idea/runConfigurations.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 11 | 12 | -------------------------------------------------------------------------------- /mydemo/src/main/res/layout/activity_main.xml: -------------------------------------------------------------------------------- 1 | 2 | 9 | 10 | 14 | 15 | 16 | -------------------------------------------------------------------------------- /app/proguard-rules.pro: -------------------------------------------------------------------------------- 1 | # Add project specific ProGuard rules here. 2 | # By default, the flags in this file are appended to flags specified 3 | # in /Users/apple/Library/Android/sdk/tools/proguard/proguard-android.txt 4 | # You can edit the include path and order by changing the proguardFiles 5 | # directive in build.gradle. 6 | # 7 | # For more details, see 8 | # http://developer.android.com/guide/developing/tools/proguard.html 9 | 10 | # Add any project specific keep options here: 11 | 12 | # If your project uses WebView with JS, uncomment the following 13 | # and specify the fully qualified class name to the JavaScript interface 14 | # class: 15 | #-keepclassmembers class fqcn.of.javascript.interface.for.webview { 16 | # public *; 17 | #} 18 | -------------------------------------------------------------------------------- /mydemo/proguard-rules.pro: -------------------------------------------------------------------------------- 1 | # Add project specific ProGuard rules here. 2 | # By default, the flags in this file are appended to flags specified 3 | # in /Users/apple/Library/Android/sdk/tools/proguard/proguard-android.txt 4 | # You can edit the include path and order by changing the proguardFiles 5 | # directive in build.gradle. 6 | # 7 | # For more details, see 8 | # http://developer.android.com/guide/developing/tools/proguard.html 9 | 10 | # Add any project specific keep options here: 11 | 12 | # If your project uses WebView with JS, uncomment the following 13 | # and specify the fully qualified class name to the JavaScript interface 14 | # class: 15 | #-keepclassmembers class fqcn.of.javascript.interface.for.webview { 16 | # public *; 17 | #} 18 | -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/feature/extension/Extension.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.feature.extension 2 | 3 | import com.fashare.hellokotlin.sugar.lambda.myForEach 4 | 5 | /** 6 | * Created by apple on 17-5-31. 7 | * 8 | * 函数拓展, 属性拓展 9 | */ 10 | fun main(args: Array) { 11 | val list = listOf("1", "2", "3", "4") 12 | 13 | // 函数拓展 14 | list.myForEach { println(it) } 15 | 16 | // 属性拓展 17 | println("last: ${list.lastItem}") 18 | } 19 | 20 | /** 21 | * 拓展 List 类, 加一个自定义的遍历方法 22 | */ 23 | fun List.myForEach(doTask: (T) -> Unit){ 24 | for(item in this) 25 | doTask(item) 26 | } 27 | 28 | /** 29 | * 拓展 List 类, 加一个自定义的长度属性 30 | */ 31 | val List.lastItem: T 32 | get() = get(size - 1) 33 | -------------------------------------------------------------------------------- /.idea/compiler.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | -------------------------------------------------------------------------------- /app/src/main/res/layout/activity_main.xml: -------------------------------------------------------------------------------- 1 | 2 | 12 | 13 | 17 | 18 | -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/sugar/interfaces/DefaultInterface.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.sugar.interfaces 2 | 3 | /** 4 | * Created by apple on 17-5-30. 5 | * 接口可以有默认实现, 类似 Java8 引入的 默认接口和 default 关键字 6 | */ 7 | interface A { 8 | fun foo() { println("A") } // 默认实现, 打印"A" 9 | fun bar() 10 | } 11 | 12 | interface B { 13 | fun foo() { println("B") } 14 | fun bar() { println("bar") } 15 | } 16 | 17 | class C : A { 18 | override fun bar() { println("bar") } 19 | } 20 | 21 | class D : A, B { 22 | override fun foo() { 23 | super.foo() 24 | super.foo() 25 | } 26 | 27 | override fun bar() { 28 | super.bar() 29 | } 30 | } 31 | 32 | fun main(args: Array){ 33 | val d: D = D() 34 | d.foo() 35 | d.bar() 36 | } 37 | 38 | 39 | -------------------------------------------------------------------------------- /mydemo/src/main/AndroidManifest.xml: -------------------------------------------------------------------------------- 1 | 2 | 4 | 5 | 6 | 7 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | -------------------------------------------------------------------------------- /mydemo/src/main/res/layout/item_story.xml: -------------------------------------------------------------------------------- 1 | 2 | 8 | 9 | 13 | 14 | 22 | 23 | 24 | -------------------------------------------------------------------------------- /app/src/main/AndroidManifest.xml: -------------------------------------------------------------------------------- 1 | 2 | 4 | 5 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | -------------------------------------------------------------------------------- /gradle.properties: -------------------------------------------------------------------------------- 1 | # Project-wide Gradle settings. 2 | 3 | # IDE (e.g. Android Studio) users: 4 | # Gradle settings configured through the IDE *will override* 5 | # any settings specified in this file. 6 | 7 | # For more details on how to configure your build environment visit 8 | # http://www.gradle.org/docs/current/userguide/build_environment.html 9 | 10 | # Specifies the JVM arguments used for the daemon process. 11 | # The setting is particularly useful for tweaking memory settings. 12 | # Default value: -Xmx10248m -XX:MaxPermSize=256m 13 | # org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8 14 | 15 | # When configured, Gradle will run in incubating parallel mode. 16 | # This option should only be used with decoupled projects. More details, visit 17 | # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects 18 | # org.gradle.parallel=true -------------------------------------------------------------------------------- /.idea/gradle.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 24 | 25 | -------------------------------------------------------------------------------- /mydemo/src/main/kotlin/com/fashare/mydemo/data/HomeInfo.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.mydemo.data 2 | 3 | import com.fashare.mydemo.R 4 | import com.fashare.no_view_holder.annotation.BindImageView 5 | import com.fashare.no_view_holder.annotation.BindImageViews 6 | import com.fashare.no_view_holder.annotation.BindRecyclerView 7 | import com.fashare.no_view_holder.annotation.BindTextView 8 | import java.util.* 9 | 10 | /** 11 | * Created by apple on 17-5-31. 12 | */ 13 | class HomeInfo(){ 14 | @BindRecyclerView(id = R.id.rv_story, layout = R.layout.item_story) 15 | val stories: List = Collections.emptyList() 16 | 17 | inner class Story{ 18 | @BindTextView(id = R.id.tv_title) 19 | val title: String = "" 20 | 21 | @BindImageViews( 22 | BindImageView(id = R.id.iv_image, placeHolder = R.drawable.ic_launcher) 23 | ) 24 | val images: List = Collections.emptyList() 25 | 26 | override fun toString(): String { 27 | return title 28 | } 29 | } 30 | } -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/sugar/safe/NullPointerSafe.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.sugar.safe 2 | 3 | /** 4 | * Created by apple on 17-5-30. 5 | * 6 | * 空安全, 编译时期的空检查, 类似 @Nullable, @NonNull 7 | */ 8 | class NullPointerSafe{ 9 | var mNullable: String? = null 10 | var mNonNull: String = "mNonNull" 11 | 12 | fun testNull(){ 13 | println("testNull: ") 14 | println(mNullable?.length) 15 | println(mNonNull.length) 16 | println() 17 | } 18 | 19 | /** 20 | * 入参严格非空, 编译时检查 21 | */ 22 | fun printList(list: List){ 23 | println("printList: ") 24 | list.forEach{ println(it) } 25 | println() 26 | } 27 | } 28 | 29 | fun main(args: Array){ 30 | val nullPointerSafe = NullPointerSafe() 31 | 32 | nullPointerSafe.testNull() 33 | 34 | var listNonNull: List = listOf("1", "2", "3", "4") 35 | nullPointerSafe.printList(listNonNull) // 入参为非空List, 正常运行 36 | 37 | // 编译错误 38 | var listNullable: List? = listOf("1", "2", "3", "4") 39 | // nullPointerSafe.printList(listNullable) // 入参为可空List, 编译错误 40 | } -------------------------------------------------------------------------------- /app/src/main/kotlin/com/fashare/hellokotlin/sugar/lambda/LambdaTest.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.hellokotlin.sugar.lambda 2 | 3 | /** 4 | * Created by apple on 17-5-30. 5 | * 6 | * lambda 表达式, 类似 java8 中的lambda 7 | */ 8 | fun main(args: Array) { 9 | // new 一个线程 10 | // 匿名类写法 11 | val runnable1 = object : Runnable{ 12 | override fun run() { 13 | println("I'm an anonymous class") 14 | } 15 | } 16 | 17 | // 函数写法, 略像js 18 | val runnable2 = fun (){ 19 | println("I'm a function") 20 | } 21 | 22 | // lambda写法1 23 | val runnable3 = Runnable { -> 24 | println("I'm a Lambda") 25 | } 26 | 27 | // lambda写法2 28 | val runnable4 = { println("I'm a Lambda") } 29 | Thread(runnable4).start() 30 | 31 | // 自定义高阶函数, lambda 表达式 作为入参 32 | listOf("1", "2", "3", "4").myForEach { println(it) } 33 | 34 | // 自定义高阶函数, lambda 表达式 作为返回值 35 | // getLogger()("I'm a Closure") 36 | var logger = getLogger() 37 | logger("I'm a Closure") 38 | } 39 | 40 | /** 41 | * 接受一个 lambda 表达式, 作为遍历任务 42 | */ 43 | fun List.myForEach(doTask: (T) -> Unit){ 44 | for(item in this) 45 | doTask(item) 46 | } 47 | 48 | /** 49 | * 返回一个 lambda 表达式(闭包), 如: 日志输出工具 logger 50 | */ 51 | fun getLogger(): (String) -> Unit{ 52 | // return { println(it) } 53 | return fun (it: String){ 54 | println(it) 55 | } 56 | } -------------------------------------------------------------------------------- /app/build.gradle: -------------------------------------------------------------------------------- 1 | apply plugin: 'com.android.application' 2 | 3 | android { 4 | compileSdkVersion rootProject.ext.compileSdkVersion as Integer 5 | buildToolsVersion rootProject.ext.buildToolsVersion as String 6 | 7 | defaultConfig { 8 | applicationId "com.fashare.hellokotlin" 9 | minSdkVersion rootProject.ext.minSdkVersion as Integer 10 | targetSdkVersion rootProject.ext.targetSdkVersion as Integer 11 | versionCode rootProject.ext.versionCode as Integer 12 | versionName rootProject.ext.versionName as String 13 | } 14 | 15 | buildTypes { 16 | release { 17 | minifyEnabled false 18 | proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 19 | } 20 | } 21 | sourceSets { 22 | main.java.srcDirs += 'src/main/kotlin' 23 | } 24 | } 25 | 26 | dependencies { 27 | compile fileTree(dir: 'libs', include: ['*.jar']) 28 | testCompile 'junit:junit:4.12' 29 | compile "com.android.support:appcompat-v7:$supportLibsVersion" 30 | } 31 | 32 | // kotlin 33 | buildscript { 34 | repositories { 35 | jcenter() 36 | } 37 | dependencies { 38 | classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion" 39 | } 40 | } 41 | 42 | apply plugin: 'kotlin-android' 43 | 44 | android { 45 | sourceSets { 46 | main.java.srcDirs += 'src/main/kotlin' 47 | } 48 | } 49 | 50 | dependencies { 51 | compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion" 52 | } 53 | repositories { 54 | mavenCentral() 55 | } 56 | 57 | 58 | -------------------------------------------------------------------------------- /mydemo/build.gradle: -------------------------------------------------------------------------------- 1 | apply plugin: 'com.android.application' 2 | apply plugin: 'android-apt' 3 | 4 | android { 5 | compileSdkVersion rootProject.ext.compileSdkVersion as Integer 6 | buildToolsVersion rootProject.ext.buildToolsVersion as String 7 | 8 | defaultConfig { 9 | minSdkVersion rootProject.ext.minSdkVersion as Integer 10 | targetSdkVersion rootProject.ext.targetSdkVersion as Integer 11 | versionCode rootProject.ext.versionCode as Integer 12 | versionName rootProject.ext.versionName as String 13 | } 14 | 15 | buildTypes { 16 | release { 17 | minifyEnabled false 18 | proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 19 | } 20 | } 21 | sourceSets { 22 | main.java.srcDirs += 'src/main/kotlin' 23 | } 24 | } 25 | 26 | dependencies { 27 | compile fileTree(dir: 'libs', include: ['*.jar']) 28 | testCompile 'junit:junit:4.12' 29 | compile "com.android.support:appcompat-v7:$supportLibsVersion" 30 | compile "com.android.support:recyclerview-v7:$supportLibsVersion" 31 | 32 | // Butter Knife 33 | compile 'com.jakewharton:butterknife:8.2.1' 34 | apt 'com.jakewharton:butterknife-compiler:8.2.1' 35 | 36 | // glide 37 | compile 'com.github.bumptech.glide:glide:3.7.0' 38 | compile 'jp.wasabeef:glide-transformations:2.0.1' 39 | 40 | // Rxjava 41 | compile 'io.reactivex:rxjava:1.1.0' 42 | compile 'io.reactivex:rxandroid:1.1.0' 43 | 44 | // Retrofit 45 | compile 'com.squareup.retrofit2:retrofit:2.0.0-beta4' 46 | compile 'com.squareup.retrofit2:adapter-rxjava:2.0.0-beta4' 47 | compile 'com.squareup.retrofit2:converter-gson:2.0.0-beta4' 48 | 49 | // Gson 50 | compile 'com.google.code.gson:gson:2.6.2' 51 | 52 | compile 'com.github.fashare2015:NoViewHolder:1.0.1' 53 | } 54 | 55 | // kotlin 56 | buildscript { 57 | repositories { 58 | jcenter() 59 | } 60 | dependencies { 61 | classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion" 62 | } 63 | } 64 | 65 | apply plugin: 'kotlin-android' 66 | 67 | android { 68 | sourceSets { 69 | main.java.srcDirs += 'src/main/kotlin' 70 | } 71 | } 72 | 73 | dependencies { 74 | compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion" 75 | } 76 | -------------------------------------------------------------------------------- /mydemo/src/main/kotlin/com/fashare/mydemo/MainActivity.kt: -------------------------------------------------------------------------------- 1 | package com.fashare.mydemo 2 | 3 | import android.app.Activity 4 | import android.os.Bundle 5 | import android.support.v4.widget.SwipeRefreshLayout 6 | import android.support.v7.app.AppCompatActivity 7 | import android.widget.Toast 8 | import butterknife.BindView 9 | import butterknife.ButterKnife 10 | import com.fashare.mydemo.data.HomeInfo 11 | import com.fashare.no_view_holder.NoViewHolder 12 | import com.fashare.no_view_holder.annotation.click.BindItemClick 13 | import com.fashare.no_view_holder.widget.NoOnItemClickListener 14 | import retrofit2.Retrofit 15 | import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory 16 | import retrofit2.converter.gson.GsonConverterFactory 17 | import rx.android.schedulers.AndroidSchedulers 18 | import rx.schedulers.Schedulers 19 | 20 | class MainActivity : AppCompatActivity() { 21 | 22 | // retrofit 网络请求 23 | val retrofit = Retrofit.Builder().baseUrl(Api.BASE_URL) 24 | .addCallAdapterFactory(RxJavaCallAdapterFactory.create()) 25 | .addConverterFactory(GsonConverterFactory.create()) 26 | .build() 27 | 28 | // NoViewHolder! 所有 view 的容器 29 | var mNoViewHolder: NoViewHolder? = null 30 | 31 | // 下拉刷新 32 | @BindView(R.id.srl_refresh) 33 | var mSrlRefresh: SwipeRefreshLayout? = null 34 | 35 | // 点击事件 36 | @BindItemClick(id = R.id.rv_story) 37 | internal var clickMeiZhi = NoOnItemClickListener { view, data, pos -> toast("click: $pos, $data") } 38 | 39 | override fun onCreate(savedInstanceState: Bundle?) { 40 | super.onCreate(savedInstanceState) 41 | setContentView(R.layout.activity_main) 42 | 43 | ButterKnife.bind(this) 44 | 45 | mNoViewHolder = NoViewHolder.Builder(this) 46 | .initView(HomeInfo()) 47 | .build() 48 | 49 | initView() 50 | loadData() 51 | } 52 | 53 | private fun initView() { 54 | mSrlRefresh?.setOnRefreshListener { loadData() } 55 | } 56 | 57 | private fun loadData() { 58 | mSrlRefresh?.setRefreshing(true) 59 | 60 | retrofit.create(Api::class.java) 61 | .getHomeInfo() 62 | .subscribeOn(Schedulers.io()) 63 | .observeOn(AndroidSchedulers.mainThread()) 64 | .subscribe({ 65 | mNoViewHolder?.notifyDataSetChanged(it) // mHomeInfo 发生变化, 通知 UI 及时刷新 66 | }, { 67 | toast("服务器跑路啦~") 68 | }, { 69 | mSrlRefresh?.setRefreshing(false) 70 | }) 71 | } 72 | } 73 | 74 | fun Activity.toast(msg: String) { 75 | Toast.makeText(this, msg, Toast.LENGTH_SHORT).show() 76 | } 77 | -------------------------------------------------------------------------------- /gradlew.bat: -------------------------------------------------------------------------------- 1 | @if "%DEBUG%" == "" @echo off 2 | @rem ########################################################################## 3 | @rem 4 | @rem Gradle startup script for Windows 5 | @rem 6 | @rem ########################################################################## 7 | 8 | @rem Set local scope for the variables with windows NT shell 9 | if "%OS%"=="Windows_NT" setlocal 10 | 11 | @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. 12 | set DEFAULT_JVM_OPTS= 13 | 14 | set DIRNAME=%~dp0 15 | if "%DIRNAME%" == "" set DIRNAME=. 16 | set APP_BASE_NAME=%~n0 17 | set APP_HOME=%DIRNAME% 18 | 19 | @rem Find java.exe 20 | if defined JAVA_HOME goto findJavaFromJavaHome 21 | 22 | set JAVA_EXE=java.exe 23 | %JAVA_EXE% -version >NUL 2>&1 24 | if "%ERRORLEVEL%" == "0" goto init 25 | 26 | echo. 27 | echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 28 | echo. 29 | echo Please set the JAVA_HOME variable in your environment to match the 30 | echo location of your Java installation. 31 | 32 | goto fail 33 | 34 | :findJavaFromJavaHome 35 | set JAVA_HOME=%JAVA_HOME:"=% 36 | set JAVA_EXE=%JAVA_HOME%/bin/java.exe 37 | 38 | if exist "%JAVA_EXE%" goto init 39 | 40 | echo. 41 | echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 42 | echo. 43 | echo Please set the JAVA_HOME variable in your environment to match the 44 | echo location of your Java installation. 45 | 46 | goto fail 47 | 48 | :init 49 | @rem Get command-line arguments, handling Windowz variants 50 | 51 | if not "%OS%" == "Windows_NT" goto win9xME_args 52 | if "%@eval[2+2]" == "4" goto 4NT_args 53 | 54 | :win9xME_args 55 | @rem Slurp the command line arguments. 56 | set CMD_LINE_ARGS= 57 | set _SKIP=2 58 | 59 | :win9xME_args_slurp 60 | if "x%~1" == "x" goto execute 61 | 62 | set CMD_LINE_ARGS=%* 63 | goto execute 64 | 65 | :4NT_args 66 | @rem Get arguments from the 4NT Shell from JP Software 67 | set CMD_LINE_ARGS=%$ 68 | 69 | :execute 70 | @rem Setup the command line 71 | 72 | set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar 73 | 74 | @rem Execute Gradle 75 | "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS% 76 | 77 | :end 78 | @rem End local scope for the variables with windows NT shell 79 | if "%ERRORLEVEL%"=="0" goto mainEnd 80 | 81 | :fail 82 | rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of 83 | rem the _cmd.exe /c_ return code! 84 | if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1 85 | exit /b 1 86 | 87 | :mainEnd 88 | if "%OS%"=="Windows_NT" endlocal 89 | 90 | :omega 91 | -------------------------------------------------------------------------------- /.idea/misc.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | 7 | 19 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 46 | 47 | 48 | 49 | 50 | 1.8 51 | 52 | 57 | 58 | 59 | 60 | 61 | 62 | -------------------------------------------------------------------------------- /gradlew: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env bash 2 | 3 | ############################################################################## 4 | ## 5 | ## Gradle start up script for UN*X 6 | ## 7 | ############################################################################## 8 | 9 | # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. 10 | DEFAULT_JVM_OPTS="" 11 | 12 | APP_NAME="Gradle" 13 | APP_BASE_NAME=`basename "$0"` 14 | 15 | # Use the maximum available, or set MAX_FD != -1 to use that value. 16 | MAX_FD="maximum" 17 | 18 | warn ( ) { 19 | echo "$*" 20 | } 21 | 22 | die ( ) { 23 | echo 24 | echo "$*" 25 | echo 26 | exit 1 27 | } 28 | 29 | # OS specific support (must be 'true' or 'false'). 30 | cygwin=false 31 | msys=false 32 | darwin=false 33 | case "`uname`" in 34 | CYGWIN* ) 35 | cygwin=true 36 | ;; 37 | Darwin* ) 38 | darwin=true 39 | ;; 40 | MINGW* ) 41 | msys=true 42 | ;; 43 | esac 44 | 45 | # Attempt to set APP_HOME 46 | # Resolve links: $0 may be a link 47 | PRG="$0" 48 | # Need this for relative symlinks. 49 | while [ -h "$PRG" ] ; do 50 | ls=`ls -ld "$PRG"` 51 | link=`expr "$ls" : '.*-> \(.*\)$'` 52 | if expr "$link" : '/.*' > /dev/null; then 53 | PRG="$link" 54 | else 55 | PRG=`dirname "$PRG"`"/$link" 56 | fi 57 | done 58 | SAVED="`pwd`" 59 | cd "`dirname \"$PRG\"`/" >/dev/null 60 | APP_HOME="`pwd -P`" 61 | cd "$SAVED" >/dev/null 62 | 63 | CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar 64 | 65 | # Determine the Java command to use to start the JVM. 66 | if [ -n "$JAVA_HOME" ] ; then 67 | if [ -x "$JAVA_HOME/jre/sh/java" ] ; then 68 | # IBM's JDK on AIX uses strange locations for the executables 69 | JAVACMD="$JAVA_HOME/jre/sh/java" 70 | else 71 | JAVACMD="$JAVA_HOME/bin/java" 72 | fi 73 | if [ ! -x "$JAVACMD" ] ; then 74 | die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME 75 | 76 | Please set the JAVA_HOME variable in your environment to match the 77 | location of your Java installation." 78 | fi 79 | else 80 | JAVACMD="java" 81 | which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 82 | 83 | Please set the JAVA_HOME variable in your environment to match the 84 | location of your Java installation." 85 | fi 86 | 87 | # Increase the maximum file descriptors if we can. 88 | if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then 89 | MAX_FD_LIMIT=`ulimit -H -n` 90 | if [ $? -eq 0 ] ; then 91 | if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then 92 | MAX_FD="$MAX_FD_LIMIT" 93 | fi 94 | ulimit -n $MAX_FD 95 | if [ $? -ne 0 ] ; then 96 | warn "Could not set maximum file descriptor limit: $MAX_FD" 97 | fi 98 | else 99 | warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT" 100 | fi 101 | fi 102 | 103 | # For Darwin, add options to specify how the application appears in the dock 104 | if $darwin; then 105 | GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\"" 106 | fi 107 | 108 | # For Cygwin, switch paths to Windows format before running java 109 | if $cygwin ; then 110 | APP_HOME=`cygpath --path --mixed "$APP_HOME"` 111 | CLASSPATH=`cygpath --path --mixed "$CLASSPATH"` 112 | JAVACMD=`cygpath --unix "$JAVACMD"` 113 | 114 | # We build the pattern for arguments to be converted via cygpath 115 | ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null` 116 | SEP="" 117 | for dir in $ROOTDIRSRAW ; do 118 | ROOTDIRS="$ROOTDIRS$SEP$dir" 119 | SEP="|" 120 | done 121 | OURCYGPATTERN="(^($ROOTDIRS))" 122 | # Add a user-defined pattern to the cygpath arguments 123 | if [ "$GRADLE_CYGPATTERN" != "" ] ; then 124 | OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)" 125 | fi 126 | # Now convert the arguments - kludge to limit ourselves to /bin/sh 127 | i=0 128 | for arg in "$@" ; do 129 | CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -` 130 | CHECK2=`echo "$arg"|egrep -c "^-"` ### Determine if an option 131 | 132 | if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then ### Added a condition 133 | eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"` 134 | else 135 | eval `echo args$i`="\"$arg\"" 136 | fi 137 | i=$((i+1)) 138 | done 139 | case $i in 140 | (0) set -- ;; 141 | (1) set -- "$args0" ;; 142 | (2) set -- "$args0" "$args1" ;; 143 | (3) set -- "$args0" "$args1" "$args2" ;; 144 | (4) set -- "$args0" "$args1" "$args2" "$args3" ;; 145 | (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;; 146 | (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;; 147 | (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;; 148 | (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;; 149 | (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;; 150 | esac 151 | fi 152 | 153 | # Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules 154 | function splitJvmOpts() { 155 | JVM_OPTS=("$@") 156 | } 157 | eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS 158 | JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME" 159 | 160 | exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@" 161 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # Kotlin的来历 2 | Kotlin的作者是大名鼎鼎的Jetbrains公司。它有一系列耳熟能详的产品，诸如Android兄弟天天用的Android Studio, IntelliJ IDEA, 还有前端的WebStorm, PhpStorm。 3 | - 2011年7月，JetBrains推出Kotlin项目。 4 | - 2012年2月，JetBrains以Apache 2许可证开源此项目。 5 | - 2016年2月15日，Kotlin v1.0（第一个官方稳定版本）发布。 6 | - 2017 Google I/O 大会，Kotlin 转正。 7 | 8 | 我个人大概是在16年年底接触到这门语言，当时由于语法上的诸多相似性，它被誉为“Android中的Swift”。说来也巧，当时正在研究ButterKnife这个框架，偶然发现它还有Kotlin版本——[kotterknife](https://github.com/JakeWharton/kotterknife)，于是就打开了新世界的大门。 9 | 10 | # 亮点 11 | 个人感觉，Kotlin最大的亮点便是可以和Java**无缝衔接**（虽然它Jvm上的兄弟Groovy,Scala也能做到）。这意味着，我们不但拥有原来java中所有的资源，还能体验到js般的编程体验（雾）。 12 | 13 | 另外，它的很多特性都分别对应java中的一个坑, 本文会从**语法糖**和**新特性**两个方面来介绍： 14 | - 语法糖 15 | - 类的简化，隐式getter()、setter() 16 | - 接口的默认实现 17 | - lambda与高阶函数 18 | - 空指针安全，编译时期的空指针检查 19 | - 流式集合操作 map(), forEach() 20 | - 新特性 21 | - 函数拓展、属性拓展 22 | - 属性代理 23 | 24 | # 简要的环境配置 25 | 根目录/build.gradle: 26 | ```gradle 27 | // external 全局变量 28 | ext{ 29 | kotlinVersion = "1.0.0-rc-1036" 30 | } 31 | ``` 32 | app/build.gradle 33 | ```gradle 34 | // kotlin 35 | buildscript { 36 | repositories { 37 | jcenter() 38 | } 39 | dependencies { 40 | classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion" 41 | } 42 | } 43 | 44 | apply plugin: 'kotlin-android' 45 | 46 | android { 47 | // 建立一个与'src/main/java'同级的kotlin工作目录 48 | sourceSets { 49 | main.java.srcDirs += 'src/main/kotlin' 50 | } 51 | } 52 | 53 | dependencies { 54 | compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion" 55 | } 56 | ``` 57 | ![目录结构，与java混编](https://raw.githubusercontent.com/fashare2015/HelloKotlin/master/screen-record/project.png) 58 | 59 | # 官方资料 60 | [Kotlin 官方参考文档 中文版](https://hltj.gitbooks.io/kotlin-reference-chinese/content/) 61 | 62 | # 详细介绍 63 | >以下每个例子附带一份源码，在(根目录/app)下 64 | 65 | ## 1. 语法糖 66 | ### 1.1 类的简化 67 | #### 1.1.1 类的定义 68 | 一切从一个简单的JavaBean说起吧。 69 | ```kotlin 70 | // java bean 71 | class People{ 72 | private String name; 73 | 74 | public People(String name){ 75 | this.name = name; 76 | } 77 | 78 | public void setName(String name){ 79 | this.name = name; 80 | } 81 | 82 | public String getName(){ 83 | return this.name; 84 | } 85 | } 86 | 87 | // kotlin bean 88 | class People(val name: String){} 89 | ``` 90 | 从我学java以来就接触了javabean这个概念，我也不懂为啥非要getter()、setter()这种东西，难道为了kpi? 可以看到同样的数据实体，在kotlin中简化至1行。变量定义和构造函数合并，同时提供隐式的getter()、setter()。 91 | 92 | #### 1.1.2 继承 93 | 下面是一段简单的继承关系： 94 | ```kotlin 95 | // 所有类默认final，要显式指定为open才可被继承 96 | open class People(val name: String){} 97 | 98 | // Code: People 表示继承关系 99 | class Coder(name: String, val language: String = "Kotlin"): People(name){ 100 | 101 | override fun toString(): String { 102 | return "name: $name, language: $language" 103 | } 104 | } 105 | 106 | // 可执行的main()方法 107 | fun main(args: Array) { 108 | val coder = Coder("Tom") 109 | 110 | println(coder) 111 | } 112 | 113 | // 输出： name: Tom, language: Kotlin 114 | ``` 115 | 116 | #### 1.1.3 数据对象 data class 117 | 在看Effective Java的时候，总是对如何正确重写hashCode(),equals(),clone()感到棘手。然而他们又是正确使用Collection的关键所在（无论是HashMap、ArrayList）。 118 | Kotlin专门提供了一个`data class`,来自动生成hashCode(),equals(),clone()。 119 | ```kotlin 120 | data class People(val name: String){} 121 | ``` 122 |
123 | 124 | ### 1.2 接口的默认实现 125 | 顾名思义，它便是指接口可以和抽象类一样，有方法体的默认实现。 126 | 我把它归结在语法糖里，是因为java8中早已有了一模一样的东西，对应的关键字叫`default`。 127 | 128 | 看起来抽象类好像可以退休了，实则不然。接口依然只是接口，不能拥有属性，只是在方法定义上更加灵活了。 129 | 130 | ```kotlin 131 | interface A { 132 | fun foo() { println("A") } // 默认实现, 打印"A" 133 | fun bar() 134 | } 135 | 136 | interface B { 137 | fun foo() { println("B") } 138 | fun bar() { println("bar") } 139 | } 140 | 141 | // 多继承时，显式指定 super.foo() 以去冲突 142 | class D : A, B { 143 | override fun foo() { 144 | super.foo() 145 | super.foo() 146 | } 147 | 148 | override fun bar() { 149 | super.bar() 150 | } 151 | } 152 | ``` 153 |
154 | 155 | ### 1.3 lambda与高阶函数 156 | #### 1.3.1 lambda 157 | lambda也不是什么新鲜玩意，在gradle、js之类的其他语言中早就玩烂了。java8中也有，不过官方迟迟不上咱也没办法。 158 | lambda本身是一个函数片段，作为一等公民，它可以作为高阶函数的参数或返回值。个人而言，我喜欢以匿名类来理解它。 159 | ```kotlin 160 | // new 一个线程 161 | // 匿名类写法 162 | val runnable1 = object : Runnable{ 163 | override fun run() { 164 | println("I'm an anonymous class") 165 | } 166 | } 167 | 168 | // 函数写法, 略像js 169 | val runnable2 = fun (){ 170 | println("I'm a function") 171 | } 172 | 173 | // lambda写法1 174 | val runnable3 = Runnable { -> 175 | println("I'm a Lambda") 176 | } 177 | 178 | // lambda写法2 179 | val runnable4 = { println("I'm a Lambda") } 180 | Thread(runnable4).start() 181 | ``` 182 | 平常习惯使用`lambda写法2`，省略匿名类的名字Runnable，以及无参数时省略箭头->。不过js那种函数写法也挺不错的。 183 | 184 | #### 1.3.2 高阶函数 185 | lambda本身作为一等公民，它是有类型的。如上例的runnable4的类型为`()->Unit`。再比如下面这个加法表达式sum的类型为`(Int, Int) -> Int`。 186 | ```kotlin 187 | val sum: (Int, Int) -> Int = { x, y -> x+y } 188 | ``` 189 | 一个变量有类型是再自然不过的事。而高阶函数的入参与返回值既然是lambda,那其类型奇怪一点也很正常。 190 | ```kotlin 191 | fun main(args: Array) { 192 | // 自定义高阶函数, lambda 表达式 作为入参 193 | listOf("1", "2", "3", "4").myForEach { println(it) } 194 | 195 | // 自定义高阶函数, lambda 表达式 作为返回值 196 | // getLogger()("I'm a Closure") 197 | var logger = getLogger() 198 | logger("I'm a Closure") 199 | } 200 | 201 | /** 202 | * 接受一个 lambda 表达式, 作为遍历任务 203 | */ 204 | fun List.myForEach(doTask: (T) -> Unit){ 205 | for(item in this) 206 | doTask(item) 207 | } 208 | 209 | /** 210 | * 返回一个 lambda 表达式(闭包), 如: 日志输出工具 logger 211 | */ 212 | fun getLogger(): (String) -> Unit{ 213 | // return { println(it) } 214 | return fun (it: String){ 215 | println(it) 216 | } 217 | } 218 | ``` 219 | PS: 看到getLogger()这种用法，你大概意识到可以像js那样写闭包了。 220 | 221 | ### 1.4 空指针安全 222 | 你也许会想空指针不是很简单的东西吗，加个if(xxx != null)判断就好了。事实上，空指针绝对是出现频率最高，最讨厌的问题。而**空安全**则是kotlin主打的一个特性之一。在java8中，我们可以借助Optional勉强做到这一点。 223 | 224 | 我们来看看是咋回事。 225 | ```kotlin 226 | var mNullable: String? = null 227 | var mNonNull: String = "mNonNull" 228 | 229 | fun testNull(){ 230 | println("testNull: ") 231 | println(mNullable?.length) 232 | println(mNonNull.length) 233 | println() 234 | } 235 | 236 | // 输出： 237 | testNull: 238 | null 239 | 8 240 | ``` 241 | kotlin定义变量时区分两种类型： 242 | - var mNullable: Any? = null 可空 243 | - var mNonNull: Any = XXX 非空 244 | 245 | 1.对一个 mNullable 你可以像普通的java类一样使用: 246 | 247 | ```kotlin 248 | // java 风格，判空 249 | if(mNullable != null) 250 | mNullable.length 251 | 252 | // kotlin 语法糖，判空(推荐) 253 | mNullable?.length 254 | ``` 255 | 2.对一个 mNonNull 则有严格的限制： 256 | 257 | ```kotlin 258 | // 不必判空，因为必然非空 259 | mNonNull.length 260 | 261 | // 编译错误(试图给非空值赋予null) 262 | mNonNull = null 263 | // 编译错误(试图给非空值赋予可空值) 264 | mNonNull = mNullable 265 | ``` 266 | 我们可以体会到mNonNull天然的好处，永不会空指针。而mNullable加上?判断，也可以达到同样的效果。 267 |
268 | 269 | ### 1.5 流式集合操作 map(), forEach() 270 | 这个我不知道怎么称呼，姑且叫流式集合操作符把。算是很普遍了，任何语言里都有，然而不支持函数式的话，写起来比较臃肿。 271 | 如下例子，一些操作符的衔接，使得操作逻辑十分清晰，之后需求变动，比如降序改为升序，也只需改动`.sortedDescending()`一行，十分灵活。 272 | ```kotlin 273 | fun main(args: Array){ 274 | val list = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10) 275 | list.filter { it%2==0 } // 取偶数 276 | .map{ it*it } // 平方 277 | .sortedDescending() // 降序排序 278 | .take(3) // 取前 3 个 279 | .forEach { println(it) } // 遍历, 打印 280 | } 281 | 282 | // 输出： 283 | 100 284 | 64 285 | 36 286 | ``` 287 |
288 | 289 | ## 2. 新特性 290 | ### 2.1 拓展 291 | 拓展这个东西，貌似是以装饰者模式来做的。它的效果是在不改源码的基础上，添加功能。比如我们要在Activity上加一个toast(),完全不用卸载基类里。这样简化了很多工作，尤其是对一些已打成jar包的类。 292 | ```kotlin 293 | fun Activity.toast(msg: String) { 294 | Toast.makeText(this, msg, Toast.LENGTH_SHORT).show() 295 | } 296 | ``` 297 | 别的例子： 298 | ```kotlin 299 | /** 300 | * Created by apple on 17-5-31. 301 | * 302 | * 函数拓展, 属性拓展 303 | */ 304 | fun main(args: Array) { 305 | val list = listOf("1", "2", "3", "4") 306 | 307 | // 函数拓展 308 | list.myForEach { println(it) } 309 | 310 | // 属性拓展 311 | println("last: ${list.lastItem}") 312 | } 313 | 314 | /** 315 | * 拓展 List 类, 加一个自定义的遍历方法 316 | */ 317 | fun List.myForEach(doTask: (T) -> Unit){ 318 | for(item in this) 319 | doTask(item) 320 | } 321 | 322 | /** 323 | * 拓展 List 类, 加一个自定义的长度属性 324 | */ 325 | val List.lastItem: T 326 | get() = get(size - 1) 327 | 328 | // 输出： 329 | 1 330 | 2 331 | 3 332 | 4 333 | last: 4 334 | ``` 335 |
336 | 337 | ### 2.2 属性代理 338 | 这个东西干嘛用呢？它把属性的get()、set()代理给了一个类，以便可以在get()和set()时做一些额外的操作。如： 339 | - 懒加载 340 | - 观察者（属性变化时，自动发出通知） 341 | - 属性非空判断 342 | - ... 343 | 344 | 以懒加载为例，lazySum可能需要复杂的运算，我们把它代理给`lazy`。 345 | 可以看到，只有第一次加载进行了计算，之后都是直接取值，提高了效率。 346 | ```kotlin 347 | val lazySum: Int by lazy { 348 | println("begin compute lazySum ...") 349 | var sum = 0 350 | for (i in 0..100) 351 | sum += i 352 | println("lazySum computed!\n") 353 | sum // 返回计算结果 354 | } 355 | 356 | fun main(args: Array) { 357 | println(lazySum) 358 | println(lazySum) 359 | } 360 | 361 | // 输出： 362 | begin compute lazySum ... 363 | lazySum computed! 364 | 365 | 5050 366 | 5050 367 | ``` 368 | 另外，我们可以自定义属性代理，之前提到的[kotterknife](https://github.com/JakeWharton/kotterknife),便是一个很好的例子（实现了bindview）: 369 | ```kotlin 370 | public class PersonView(context: Context, attrs: AttributeSet?) : LinearLayout(context, attrs) { 371 | val firstName: TextView by bindView(R.id.first_name) 372 | val lastName: TextView by bindView(R.id.last_name) 373 | 374 | // Optional binding. 375 | val details: TextView? by bindOptionalView(R.id.details) 376 | } 377 | ``` 378 |
379 | 380 | # Demo实战 381 | 用 kotlin 结合一些流行第三方库 + 知乎日报api 做了一个简易的demo，在模块（根目录/mydemo）中： 382 | - Butter Knife 383 | - Retrofit 384 | - Gson 385 | - Rxjava 386 | - Glide 387 | - 个人库 NoViewHolder 388 | 389 | ![MyDemo: kotlin小栗子](https://raw.githubusercontent.com/fashare2015/HelloKotlin/master/screen-record/mydemo.jpg) 390 | 391 |
392 | 393 | # 感谢 394 | [Kotlin 官方参考文档 中文版](https://hltj.gitbooks.io/kotlin-reference-chinese/content/) 395 | 396 | [为什么说Kotlin值得一试](http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2016/0226/4000.html) 397 | 398 | --------------------------------------------------------------------------------