├── .gitignore
├── .idea
├── codeStyles
│ ├── Project.xml
│ └── codeStyleConfig.xml
├── gradle.xml
├── misc.xml
├── runConfigurations.xml
└── vcs.xml
├── app
├── .gitignore
├── build.gradle
├── proguard-rules.pro
└── src
│ ├── androidTest
│ └── java
│ │ └── supahsoftware
│ │ └── androidexamplecarousel
│ │ └── ExampleInstrumentedTest.kt
│ ├── main
│ ├── AndroidManifest.xml
│ ├── java
│ │ └── supahsoftware
│ │ │ └── androidexamplecarousel
│ │ │ ├── HorizontalCarouselRecyclerView.kt
│ │ │ ├── ItemAdapter.kt
│ │ │ └── MainActivity.kt
│ └── res
│ │ ├── drawable-v24
│ │ └── ic_launcher_foreground.xml
│ │ ├── drawable
│ │ ├── ic_airplane.xml
│ │ ├── ic_car.xml
│ │ ├── ic_food.xml
│ │ ├── ic_gas.xml
│ │ ├── ic_home.xml
│ │ ├── ic_launcher_background.xml
│ │ └── icon_background_blue.xml
│ │ ├── layout
│ │ ├── activity_main.xml
│ │ └── list_item.xml
│ │ ├── mipmap-anydpi-v26
│ │ ├── ic_launcher.xml
│ │ └── ic_launcher_round.xml
│ │ ├── mipmap-hdpi
│ │ ├── ic_launcher.png
│ │ └── ic_launcher_round.png
│ │ ├── mipmap-mdpi
│ │ ├── ic_launcher.png
│ │ └── ic_launcher_round.png
│ │ ├── mipmap-xhdpi
│ │ ├── ic_launcher.png
│ │ └── ic_launcher_round.png
│ │ ├── mipmap-xxhdpi
│ │ ├── ic_launcher.png
│ │ └── ic_launcher_round.png
│ │ ├── mipmap-xxxhdpi
│ │ ├── ic_launcher.png
│ │ └── ic_launcher_round.png
│ │ └── values
│ │ ├── colors.xml
│ │ ├── strings.xml
│ │ └── styles.xml
│ └── test
│ └── java
│ └── supahsoftware
│ └── androidexamplecarousel
│ └── ExampleUnitTest.kt
├── build.gradle
├── gradle.properties
├── gradle
└── wrapper
│ ├── gradle-wrapper.jar
│ └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
└── settings.gradle
/.gitignore:
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1 | *.iml
2 | .gradle
3 | /local.properties
4 | /.idea/caches
5 | /.idea/libraries
6 | /.idea/modules.xml
7 | /.idea/workspace.xml
8 | /.idea/navEditor.xml
9 | /.idea/assetWizardSettings.xml
10 | .DS_Store
11 | /build
12 | /captures
13 | .externalNativeBuild
14 |
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/.idea/codeStyles/Project.xml:
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/app/.gitignore:
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1 | /build
2 |
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/app/build.gradle:
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1 | apply plugin: 'com.android.application'
2 | apply plugin: 'kotlin-android'
3 | apply plugin: 'kotlin-android-extensions'
4 |
5 | android {
6 | compileSdkVersion 28
7 | defaultConfig {
8 | applicationId "supahsoftware.androidexamplecarousel"
9 | minSdkVersion 21
10 | targetSdkVersion 28
11 | versionCode 1
12 | versionName "1.0"
13 | testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
14 | }
15 | buildTypes {
16 | release {
17 | minifyEnabled false
18 | proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
19 | }
20 | }
21 | }
22 |
23 | dependencies {
24 | implementation fileTree(dir: 'libs', include: ['*.jar'])
25 | implementation"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
26 | implementation 'androidx.appcompat:appcompat:1.0.2'
27 | implementation 'com.google.android.material:material:1.0.0'
28 | }
29 |
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/app/proguard-rules.pro:
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1 | # Add project specific ProGuard rules here.
2 | # You can control the set of applied configuration files using the
3 | # proguardFiles setting in build.gradle.
4 | #
5 | # For more details, see
6 | # http://developer.android.com/guide/developing/tools/proguard.html
7 |
8 | # If your project uses WebView with JS, uncomment the following
9 | # and specify the fully qualified class name to the JavaScript interface
10 | # class:
11 | #-keepclassmembers class fqcn.of.javascript.interface.for.webview {
12 | # public *;
13 | #}
14 |
15 | # Uncomment this to preserve the line number information for
16 | # debugging stack traces.
17 | #-keepattributes SourceFile,LineNumberTable
18 |
19 | # If you keep the line number information, uncomment this to
20 | # hide the original source file name.
21 | #-renamesourcefileattribute SourceFile
22 |
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/app/src/androidTest/java/supahsoftware/androidexamplecarousel/ExampleInstrumentedTest.kt:
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1 | package supahsoftware.androidexamplecarousel
2 |
3 | import android.support.test.InstrumentationRegistry
4 | import android.support.test.runner.AndroidJUnit4
5 |
6 | import org.junit.Test
7 | import org.junit.runner.RunWith
8 |
9 | import org.junit.Assert.*
10 |
11 | /**
12 | * Instrumented test, which will execute on an Android device.
13 | *
14 | * See [testing documentation](http://d.android.com/tools/testing).
15 | */
16 | @RunWith(AndroidJUnit4::class)
17 | class ExampleInstrumentedTest {
18 | @Test
19 | fun useAppContext() {
20 | // Context of the app under test.
21 | val appContext = InstrumentationRegistry.getTargetContext()
22 | assertEquals("supahsoftware.androidexamplecarousel", appContext.packageName)
23 | }
24 | }
25 |
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/app/src/main/AndroidManifest.xml:
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/app/src/main/java/supahsoftware/androidexamplecarousel/HorizontalCarouselRecyclerView.kt:
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1 | package supahsoftware.androidexamplecarousel
2 |
3 | import android.animation.ArgbEvaluator
4 | import android.content.Context
5 | import android.graphics.ColorMatrix
6 | import android.graphics.ColorMatrixColorFilter
7 | import android.util.AttributeSet
8 | import android.view.View
9 | import android.widget.ImageView
10 | import android.widget.TextView
11 | import androidx.core.content.ContextCompat
12 | import androidx.recyclerview.widget.LinearLayoutManager
13 | import androidx.recyclerview.widget.RecyclerView
14 |
15 | class HorizontalCarouselRecyclerView(
16 | context: Context,
17 | attrs: AttributeSet
18 | ) : RecyclerView(context, attrs) {
19 |
20 | private val activeColor by lazy { ContextCompat.getColor(context, R.color.blue) }
21 | private val inactiveColor by lazy { ContextCompat.getColor(context, R.color.gray) }
22 | private var viewsToChangeColor: List = listOf()
23 |
24 | fun initialize(newAdapter: Adapter) {
25 | layoutManager = LinearLayoutManager(context, HORIZONTAL, false)
26 | newAdapter.registerAdapterDataObserver(object : RecyclerView.AdapterDataObserver() {
27 | override fun onChanged() {
28 | post {
29 | val sidePadding = (width / 2) - (getChildAt(0).width / 2)
30 | setPadding(sidePadding, 0, sidePadding, 0)
31 | scrollToPosition(0)
32 | addOnScrollListener(object : OnScrollListener() {
33 | override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {
34 | super.onScrolled(recyclerView, dx, dy)
35 | onScrollChanged()
36 | }
37 | })
38 | }
39 | }
40 | })
41 | adapter = newAdapter
42 | }
43 |
44 | fun setViewsToChangeColor(viewIds: List) {
45 | viewsToChangeColor = viewIds
46 | }
47 |
48 | private fun onScrollChanged() {
49 | post {
50 | (0 until childCount).forEach { position ->
51 | val child = getChildAt(position)
52 | val childCenterX = (child.left + child.right) / 2
53 | val scaleValue = getGaussianScale(childCenterX, 1f, 1f, 150.toDouble())
54 | child.scaleX = scaleValue
55 | child.scaleY = scaleValue
56 | colorView(child, scaleValue)
57 | }
58 | }
59 | }
60 |
61 | private fun colorView(child: View, scaleValue: Float) {
62 | val saturationPercent = (scaleValue - 1) / 1f
63 | val alphaPercent = scaleValue / 2f
64 | val matrix = ColorMatrix()
65 | matrix.setSaturation(saturationPercent)
66 |
67 | viewsToChangeColor.forEach { viewId ->
68 | val viewToChangeColor = child.findViewById(viewId)
69 | when (viewToChangeColor) {
70 | is ImageView -> {
71 | viewToChangeColor.colorFilter = ColorMatrixColorFilter(matrix)
72 | viewToChangeColor.imageAlpha = (255 * alphaPercent).toInt()
73 | }
74 | is TextView -> {
75 | val textColor = ArgbEvaluator().evaluate(saturationPercent, inactiveColor, activeColor) as Int
76 | viewToChangeColor.setTextColor(textColor)
77 | }
78 | }
79 | }
80 | }
81 |
82 | private fun getGaussianScale(
83 | childCenterX: Int,
84 | minScaleOffest: Float,
85 | scaleFactor: Float,
86 | spreadFactor: Double
87 | ): Float {
88 | val recyclerCenterX = (left + right) / 2
89 | return (Math.pow(
90 | Math.E,
91 | -Math.pow(childCenterX - recyclerCenterX.toDouble(), 2.toDouble()) / (2 * Math.pow(
92 | spreadFactor,
93 | 2.toDouble()
94 | ))
95 | ) * scaleFactor + minScaleOffest).toFloat()
96 | }
97 |
98 | }
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/app/src/main/java/supahsoftware/androidexamplecarousel/ItemAdapter.kt:
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1 | package supahsoftware.androidexamplecarousel
2 |
3 | import android.view.LayoutInflater
4 | import android.view.View
5 | import android.view.ViewGroup
6 | import androidx.recyclerview.widget.RecyclerView
7 | import kotlinx.android.synthetic.main.list_item.view.*
8 |
9 | class ItemAdapter(val itemClick: (position:Int,item:Item) -> Unit) : RecyclerView.Adapter() {
10 |
11 | private var items: List- = listOf()
12 |
13 | override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ItemViewHolder =
14 | ItemViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.list_item, parent, false))
15 |
16 | override fun onBindViewHolder(holder: ItemViewHolder, position: Int) {
17 | holder.bind(items[position])
18 | holder.itemView.setOnClickListener {
19 | itemClick(position,items[position])
20 | }
21 | }
22 |
23 | override fun getItemCount() = items.size
24 |
25 | fun setItems(newItems: List
- ) {
26 | items = newItems
27 | notifyDataSetChanged()
28 | }
29 | }
30 |
31 | class ItemViewHolder(private val view: View) : RecyclerView.ViewHolder(view) {
32 | fun bind(item: Item) {
33 | view.list_item_text.text = "${item.title}"
34 | view.list_item_icon.setImageResource(item.icon)
35 | }
36 | }
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/app/src/main/java/supahsoftware/androidexamplecarousel/MainActivity.kt:
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1 | package supahsoftware.androidexamplecarousel
2 |
3 | import android.os.Bundle
4 | import android.widget.Toast
5 | import androidx.annotation.DrawableRes
6 | import androidx.appcompat.app.AppCompatActivity
7 | import kotlinx.android.synthetic.main.activity_main.*
8 |
9 | class MainActivity : AppCompatActivity() {
10 |
11 | private val itemAdapter by lazy {
12 | ItemAdapter { position: Int, item: Item ->
13 | Toast.makeText(this@MainActivity, "Pos ${position}", Toast.LENGTH_LONG).show()
14 | item_list.smoothScrollToPosition(position)
15 | } }
16 | private val possibleItems = listOf(
17 | Item("Airplanes", R.drawable.ic_airplane),
18 | Item("Cars", R.drawable.ic_car),
19 | Item("Food", R.drawable.ic_food),
20 | Item("Gas", R.drawable.ic_gas),
21 | Item("Home", R.drawable.ic_home)
22 | )
23 |
24 | override fun onCreate(savedInstanceState: Bundle?) {
25 | super.onCreate(savedInstanceState)
26 | setContentView(R.layout.activity_main)
27 |
28 | item_list.initialize(itemAdapter)
29 | item_list.setViewsToChangeColor(listOf(R.id.list_item_background, R.id.list_item_text))
30 | itemAdapter.setItems(getLargeListOfItems())
31 | }
32 |
33 | private fun getLargeListOfItems(): List
- {
34 | val items = mutableListOf
- ()
35 | (0..40).map { items.add(possibleItems.random()) }
36 | return items
37 | }
38 | }
39 |
40 | data class Item(
41 | val title: String,
42 | @DrawableRes val icon: Int
43 | )
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/app/src/main/res/drawable-v24/ic_launcher_foreground.xml:
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