├── .gitignore ├── LICENSE ├── README.md ├── app ├── .gitignore ├── build.gradle ├── proguard-rules.pro └── src │ ├── androidTest │ └── java │ │ └── com │ │ └── dant │ │ └── centeringrecyclerview │ │ └── ExampleInstrumentedTest.java │ ├── main │ ├── AndroidManifest.xml │ ├── assets │ │ └── demo.gif │ ├── java │ │ └── com │ │ │ └── dant │ │ │ └── centeringrecyclerview │ │ │ ├── ExampleDateAdapter.java │ │ │ ├── ExampleDateEndPaddingItemDecoration.java │ │ │ ├── ExampleDateReyclerViewHolder.java │ │ │ └── MainActivity.java │ └── res │ │ ├── layout │ │ ├── activity_main.xml │ │ └── example_date_viewholder.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 │ │ └── values │ │ ├── colors.xml │ │ ├── dimens.xml │ │ ├── strings.xml │ │ └── styles.xml │ └── test │ └── java │ └── com │ └── dant │ └── centeringrecyclerview │ └── ExampleUnitTest.java ├── build.gradle ├── gradle.properties ├── gradle └── wrapper │ ├── gradle-wrapper.jar │ └── gradle-wrapper.properties ├── gradlew ├── gradlew.bat ├── settings.gradle └── snappy-recyclerview ├── .gitignore ├── build.gradle ├── proguard-rules.pro └── src ├── androidTest └── java │ └── com │ └── dant │ └── centersnapreyclerview │ └── ExampleInstrumentedTest.java ├── main ├── AndroidManifest.xml ├── java │ └── com │ │ └── dant │ │ └── centersnapreyclerview │ │ ├── CenterLayoutManager.java │ │ └── SnappingRecyclerView.java └── res │ └── values │ ├── snapping_recyclerview.xml │ └── strings.xml └── test └── java └── com └── dant └── centersnapreyclerview └── ExampleUnitTest.java /.gitignore: -------------------------------------------------------------------------------- 1 | # Built application files 2 | *.apk 3 | *.ap_ 4 | 5 | # Files for the ART/Dalvik VM 6 | *.dex 7 | 8 | # Java class files 9 | *.class 10 | 11 | # Generated files 12 | bin/ 13 | gen/ 14 | out/ 15 | 16 | # Gradle files 17 | .gradle/ 18 | build/ 19 | 20 | # Local configuration file (sdk path, etc) 21 | local.properties 22 | 23 | # Proguard folder generated by Eclipse 24 | proguard/ 25 | 26 | # Log Files 27 | *.log 28 | 29 | # Android Studio Navigation editor temp files 30 | .navigation/ 31 | 32 | # Android Studio captures folder 33 | captures/ 34 | 35 | # Intellij 36 | *.iml 37 | .idea/workspace.xml 38 | CenteringRecyclerView/.idea/workspace.xml 39 | 40 | # Keystore files 41 | *.jks 42 | 43 | .idea/* 44 | 45 | # Bintray files 46 | snappy-recyclerview/bintray.gradle 47 | snappy-recyclerview/install.gradle 48 | 49 | 50 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | MIT License 2 | 3 | Copyright (c) 2017 Dan-TD 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in all 13 | copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 | SOFTWARE. 22 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | [![Build Status](https://www.bitrise.io/app/5148ffd6da031702.svg?token=sZ7oWu0dY7qzMDrhZ01Enw&branch=develop)](https://www.bitrise.io/app/5148ffd6da031702) 2 | [![Android Arsenal](https://img.shields.io/badge/Android%20Arsenal-Snappy%20RecyclerView-brightgreen.svg?style=flat)](https://android-arsenal.com/details/1/5473) 3 | [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT) 4 | 5 | # SnappyRecyclerView 6 | 7 | An extension to RecyclerView which will snap to child Views to the specified anchor, START, CENTER or END. 8 | 9 |
10 | Demo Screen Capture 11 | 12 | ## Setup 13 | 14 | #### Gradle 15 | 16 | `compile 'com.github.dan-td:snappy-recyclerview:1.0.2'` 17 | 18 | #### Maven 19 | ``` 20 | 21 | com.github.dan-td 22 | snappy-recyclerview 23 | 1.0.2 24 | 25 | ``` 26 | 27 | ## Sample Usage 28 | 29 | ```xml 30 | 35 | ``` 36 | 37 | ### XML Attributes 38 | 39 | * **orientation** - the orientation of the recyclerview, VERTICAL or HORIZONTAL 40 | * **anchor** - the snap anchor of the recyclerview, START, CENTER or END 41 | * **scrollSpeed** - the smooth scroll speed 42 | * **flingThreshold** - the threshold above which a fling is will occur 43 | 44 | ## License 45 | 46 | ``` 47 | Copyright 2017 Daniel Tanner-Davies 48 | 49 | Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: 50 | 51 | The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. 52 | 53 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 54 | ``` 55 | -------------------------------------------------------------------------------- /app/.gitignore: -------------------------------------------------------------------------------- 1 | /build -------------------------------------------------------------------------------- /app/build.gradle: -------------------------------------------------------------------------------- 1 | apply plugin: 'com.android.application' 2 | 3 | android { 4 | compileSdkVersion 25 5 | buildToolsVersion "25.0.0" 6 | defaultConfig { 7 | applicationId "com.dant.centeringrecyclerview" 8 | minSdkVersion 19 9 | targetSdkVersion 25 10 | versionCode 1 11 | versionName "1.0" 12 | testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" 13 | } 14 | buildTypes { 15 | release { 16 | minifyEnabled false 17 | proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 18 | } 19 | } 20 | } 21 | 22 | dependencies { 23 | compile fileTree(dir: 'libs', include: ['*.jar']) 24 | androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { 25 | exclude group: 'com.android.support', module: 'support-annotations' 26 | }) 27 | compile 'com.android.support:appcompat-v7:25.0.1' 28 | compile 'com.android.support:recyclerview-v7:25.0.1' 29 | compile 'com.android.support:cardview-v7:25.0.1' 30 | compile project(':snappy-recyclerview') 31 | testCompile 'junit:junit:4.12' 32 | } 33 | -------------------------------------------------------------------------------- /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/dant/Library/android-sdk-macosx/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/androidTest/java/com/dant/centeringrecyclerview/ExampleInstrumentedTest.java: -------------------------------------------------------------------------------- 1 | package com.dant.centeringrecyclerview; 2 | 3 | import android.content.Context; 4 | import android.support.test.InstrumentationRegistry; 5 | import android.support.test.runner.AndroidJUnit4; 6 | 7 | import org.junit.Test; 8 | import org.junit.runner.RunWith; 9 | 10 | import static org.junit.Assert.*; 11 | 12 | /** 13 | * Instrumentation test, which will execute on an Android device. 14 | * 15 | * @see Testing documentation 16 | */ 17 | @RunWith(AndroidJUnit4.class) 18 | public class ExampleInstrumentedTest { 19 | @Test 20 | public void useAppContext() throws Exception { 21 | // Context of the app under test. 22 | Context appContext = InstrumentationRegistry.getTargetContext(); 23 | 24 | assertEquals("com.dant.centeringrecyclerview", appContext.getPackageName()); 25 | } 26 | } 27 | -------------------------------------------------------------------------------- /app/src/main/AndroidManifest.xml: -------------------------------------------------------------------------------- 1 | 2 | 4 | 5 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | -------------------------------------------------------------------------------- /app/src/main/assets/demo.gif: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/app/src/main/assets/demo.gif -------------------------------------------------------------------------------- /app/src/main/java/com/dant/centeringrecyclerview/ExampleDateAdapter.java: -------------------------------------------------------------------------------- 1 | package com.dant.centeringrecyclerview; 2 | 3 | import android.support.v7.widget.RecyclerView; 4 | import android.view.ViewGroup; 5 | 6 | import java.text.ParseException; 7 | import java.text.SimpleDateFormat; 8 | import java.util.ArrayList; 9 | import java.util.Calendar; 10 | import java.util.Date; 11 | import java.util.List; 12 | 13 | public class ExampleDateAdapter extends RecyclerView.Adapter { 14 | 15 | private Date startDate; 16 | private Date endDate; 17 | 18 | private List dates; 19 | 20 | public ExampleDateAdapter() { 21 | SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); 22 | 23 | try { 24 | startDate = formatter.parse("2017-01-01"); 25 | } catch (ParseException ex) {} 26 | 27 | try { 28 | endDate = formatter.parse("2018-12-31"); 29 | } catch (ParseException ex) {} 30 | 31 | Calendar start = Calendar.getInstance(); 32 | start.setTime(startDate); 33 | 34 | Calendar end = Calendar.getInstance(); 35 | end.setTime(endDate); 36 | 37 | dates = new ArrayList<>(); 38 | for(Date date = start.getTime(); start.before(end); start.add(Calendar.DATE, 1), date = start.getTime()) { 39 | dates.add(date); 40 | } 41 | } 42 | 43 | @Override 44 | public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 45 | return new ExampleDateReyclerViewHolder(parent); 46 | } 47 | 48 | @Override 49 | public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { 50 | ((ExampleDateReyclerViewHolder)holder).setDate(dates.get(position)); 51 | } 52 | 53 | @Override 54 | public int getItemCount() { 55 | return dates.size(); 56 | } 57 | } 58 | -------------------------------------------------------------------------------- /app/src/main/java/com/dant/centeringrecyclerview/ExampleDateEndPaddingItemDecoration.java: -------------------------------------------------------------------------------- 1 | package com.dant.centeringrecyclerview; 2 | 3 | import android.graphics.Rect; 4 | import android.support.v7.widget.RecyclerView; 5 | import android.view.View; 6 | 7 | import com.dant.centersnapreyclerview.SnappingRecyclerView; 8 | 9 | public class ExampleDateEndPaddingItemDecoration extends RecyclerView.ItemDecoration { 10 | 11 | private @SnappingRecyclerView.OrientationMode int orientation; 12 | 13 | public ExampleDateEndPaddingItemDecoration(@SnappingRecyclerView.OrientationMode int orientation) { 14 | this.orientation = orientation; 15 | } 16 | 17 | @Override 18 | public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { 19 | if(parent.getChildAdapterPosition(view) == 0) { 20 | if(orientation == SnappingRecyclerView.VERTICAL) { 21 | outRect.top = (parent.getHeight() / 2) - (view.getHeight() / 2); 22 | } else { 23 | outRect.left = (parent.getWidth() / 2) - (view.getWidth() / 2); 24 | } 25 | } else if (parent.getChildAdapterPosition(view) == parent.getAdapter().getItemCount() - 1) { 26 | if(orientation == SnappingRecyclerView.VERTICAL) { 27 | outRect.bottom = (parent.getHeight() / 2) - (view.getHeight() / 2); 28 | } else { 29 | outRect.right = (parent.getWidth() / 2) - (view.getWidth() / 2); 30 | } 31 | } 32 | } 33 | } 34 | -------------------------------------------------------------------------------- /app/src/main/java/com/dant/centeringrecyclerview/ExampleDateReyclerViewHolder.java: -------------------------------------------------------------------------------- 1 | package com.dant.centeringrecyclerview; 2 | 3 | import android.support.v7.widget.RecyclerView; 4 | import android.view.LayoutInflater; 5 | import android.view.ViewGroup; 6 | import android.widget.TextView; 7 | 8 | import java.text.SimpleDateFormat; 9 | import java.util.Calendar; 10 | import java.util.Date; 11 | 12 | public class ExampleDateReyclerViewHolder extends RecyclerView.ViewHolder { 13 | 14 | public ExampleDateReyclerViewHolder(ViewGroup parent) { 15 | super(LayoutInflater.from(parent.getContext()).inflate(R.layout.example_date_viewholder, parent, false)); 16 | } 17 | 18 | public void setDate(Date date) { 19 | ((TextView)(itemView.findViewById(R.id.date_text))).setText(new SimpleDateFormat("EEE d").format(date)); 20 | ((TextView)(itemView.findViewById(R.id.month_text))).setText(new SimpleDateFormat("MMM").format(date)); 21 | } 22 | } 23 | -------------------------------------------------------------------------------- /app/src/main/java/com/dant/centeringrecyclerview/MainActivity.java: -------------------------------------------------------------------------------- 1 | package com.dant.centeringrecyclerview; 2 | 3 | import android.support.v7.app.AppCompatActivity; 4 | import android.os.Bundle; 5 | 6 | import com.dant.centersnapreyclerview.SnappingRecyclerView; 7 | 8 | public class MainActivity extends AppCompatActivity { 9 | 10 | @Override 11 | protected void onCreate(Bundle savedInstanceState) { 12 | super.onCreate(savedInstanceState); 13 | 14 | setContentView(R.layout.activity_main); 15 | 16 | SnappingRecyclerView recyclerView = (SnappingRecyclerView) findViewById(R.id.recyclerview); 17 | recyclerView.addItemDecoration(new ExampleDateEndPaddingItemDecoration(recyclerView.getOrientation())); 18 | recyclerView.setAdapter(new ExampleDateAdapter()); 19 | } 20 | } -------------------------------------------------------------------------------- /app/src/main/res/layout/activity_main.xml: -------------------------------------------------------------------------------- 1 | 2 | 9 | 10 | 18 | 19 | 20 | -------------------------------------------------------------------------------- /app/src/main/res/layout/example_date_viewholder.xml: -------------------------------------------------------------------------------- 1 | 2 | 11 | 12 | 16 | 17 | 22 | 23 | 31 | 32 | 40 | 41 | 42 | 43 | 44 | 45 | -------------------------------------------------------------------------------- /app/src/main/res/mipmap-hdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/app/src/main/res/mipmap-hdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-mdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/app/src/main/res/mipmap-mdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-xhdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/app/src/main/res/mipmap-xhdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-xxhdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/app/src/main/res/mipmap-xxhdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/mipmap-xxxhdpi/ic_launcher.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/app/src/main/res/mipmap-xxxhdpi/ic_launcher.png -------------------------------------------------------------------------------- /app/src/main/res/values-w820dp/dimens.xml: -------------------------------------------------------------------------------- 1 | 2 | 5 | 64dp 6 | 7 | -------------------------------------------------------------------------------- /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 | -------------------------------------------------------------------------------- /app/src/main/res/values/strings.xml: -------------------------------------------------------------------------------- 1 | 2 | Centering RecyclerView 3 | 4 | -------------------------------------------------------------------------------- /app/src/main/res/values/styles.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 10 | 11 | 12 | -------------------------------------------------------------------------------- /app/src/test/java/com/dant/centeringrecyclerview/ExampleUnitTest.java: -------------------------------------------------------------------------------- 1 | package com.dant.centeringrecyclerview; 2 | 3 | import org.junit.Test; 4 | 5 | import static org.junit.Assert.*; 6 | 7 | /** 8 | * Example local unit test, which will execute on the development machine (host). 9 | * 10 | * @see Testing documentation 11 | */ 12 | public class ExampleUnitTest { 13 | @Test 14 | public void addition_isCorrect() throws Exception { 15 | assertEquals(4, 2 + 2); 16 | } 17 | } -------------------------------------------------------------------------------- /build.gradle: -------------------------------------------------------------------------------- 1 | // Top-level build file where you can add configuration options common to all sub-projects/modules. 2 | 3 | buildscript { 4 | repositories { 5 | jcenter() 6 | } 7 | dependencies { 8 | classpath 'com.android.tools.build:gradle:2.2.2' 9 | 10 | // NOTE: Do not place your application dependencies here; they belong 11 | // in the individual module build.gradle files 12 | classpath 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.2' 13 | classpath 'com.github.dcendents:android-maven-gradle-plugin:1.4.1' 14 | } 15 | } 16 | 17 | allprojects { 18 | repositories { 19 | jcenter() 20 | } 21 | } 22 | 23 | task clean(type: Delete) { 24 | delete rootProject.buildDir 25 | } 26 | -------------------------------------------------------------------------------- /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 | org.gradle.jvmargs=-Xmx1536m 13 | 14 | # When configured, Gradle will run in incubating parallel mode. 15 | # This option should only be used with decoupled projects. More details, visit 16 | # http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects 17 | # org.gradle.parallel=true 18 | -------------------------------------------------------------------------------- /gradle/wrapper/gradle-wrapper.jar: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/Dan-TD/SnappyRecyclerView/3d2f35ea66d48de59027b529153e931aa57683ae/gradle/wrapper/gradle-wrapper.jar -------------------------------------------------------------------------------- /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-2.14.1-all.zip 7 | -------------------------------------------------------------------------------- /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 | -------------------------------------------------------------------------------- /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 | -------------------------------------------------------------------------------- /settings.gradle: -------------------------------------------------------------------------------- 1 | include ':app', ':snappy-recyclerview' 2 | -------------------------------------------------------------------------------- /snappy-recyclerview/.gitignore: -------------------------------------------------------------------------------- 1 | /build -------------------------------------------------------------------------------- /snappy-recyclerview/build.gradle: -------------------------------------------------------------------------------- 1 | apply plugin: 'com.android.library' 2 | 3 | android { 4 | compileSdkVersion 25 5 | buildToolsVersion "25.0.0" 6 | 7 | defaultConfig { 8 | minSdkVersion 16 9 | targetSdkVersion 25 10 | versionCode 1 11 | versionName "1.0.2" 12 | 13 | testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" 14 | 15 | } 16 | buildTypes { 17 | release { 18 | minifyEnabled false 19 | proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 20 | } 21 | } 22 | } 23 | 24 | dependencies { 25 | compile fileTree(dir: 'libs', include: ['*.jar']) 26 | androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { 27 | exclude group: 'com.android.support', module: 'support-annotations' 28 | }) 29 | compile 'com.android.support:appcompat-v7:25.0.1' 30 | compile 'com.android.support:recyclerview-v7:25.0.1' 31 | testCompile 'junit:junit:4.12' 32 | } 33 | 34 | // apply from: 'install.gradle' 35 | // apply from: 'bintray.gradle' 36 | -------------------------------------------------------------------------------- /snappy-recyclerview/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/dant/Library/android-sdk-macosx/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 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/androidTest/java/com/dant/centersnapreyclerview/ExampleInstrumentedTest.java: -------------------------------------------------------------------------------- 1 | package com.dant.centersnapreyclerview; 2 | 3 | import android.content.Context; 4 | import android.support.test.InstrumentationRegistry; 5 | import android.support.test.runner.AndroidJUnit4; 6 | 7 | import org.junit.Test; 8 | import org.junit.runner.RunWith; 9 | 10 | import static org.junit.Assert.*; 11 | 12 | /** 13 | * Instrumentation test, which will execute on an Android device. 14 | * 15 | * @see Testing documentation 16 | */ 17 | @RunWith(AndroidJUnit4.class) 18 | public class ExampleInstrumentedTest { 19 | @Test 20 | public void useAppContext() throws Exception { 21 | // Context of the app under test. 22 | Context appContext = InstrumentationRegistry.getTargetContext(); 23 | 24 | assertEquals("com.dant.centersnapreyclerview.test", appContext.getPackageName()); 25 | } 26 | } 27 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/main/AndroidManifest.xml: -------------------------------------------------------------------------------- 1 | 3 | 4 | 7 | 8 | 9 | 10 | 11 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/main/java/com/dant/centersnapreyclerview/CenterLayoutManager.java: -------------------------------------------------------------------------------- 1 | package com.dant.centersnapreyclerview; 2 | 3 | import android.content.Context; 4 | import android.graphics.PointF; 5 | import android.support.v7.widget.LinearLayoutManager; 6 | import android.support.v7.widget.LinearSmoothScroller; 7 | import android.support.v7.widget.RecyclerView; 8 | import android.util.DisplayMetrics; 9 | 10 | /** 11 | * This extension to LinearLayoutManager allows the smoothScroll speed to be adjusted, additionally 12 | * it provides a custom implementation of the LinearSmoothScroller. The extension of 13 | * LinearSmoothScroller provides an additional snap preference, CENTER, this aligns the center of 14 | * the child's View with the center of the parent's View. 15 | */ 16 | public class CenterLayoutManager extends LinearLayoutManager { 17 | 18 | private SmoothScroller smoothScroller; 19 | 20 | private int anchor; 21 | 22 | public CenterLayoutManager(Context context) { 23 | super(context); 24 | 25 | smoothScroller = new SmoothScroller(context); 26 | } 27 | 28 | public void setAnchor(int anchor) { 29 | this.anchor = anchor; 30 | } 31 | 32 | public void setScrollSpeed(float scrollSpeed) { 33 | smoothScroller.setScrollSpeed(scrollSpeed); 34 | } 35 | 36 | @Override 37 | public void smoothScrollToPosition(RecyclerView recyclerView, 38 | RecyclerView.State state, final int position) { 39 | smoothScroller.setTargetPosition(position); 40 | startSmoothScroll(smoothScroller); 41 | } 42 | 43 | private class SmoothScroller extends LinearSmoothScroller { 44 | 45 | private static final float MILLISECONDS_PER_INCH = 100f; 46 | 47 | /** 48 | * Use in calculating the scroll speed. 49 | * The time (in ms) it takes to scroll an inch. 50 | */ 51 | private float milliSecondsPerInch = -1; 52 | 53 | public SmoothScroller(Context context) { 54 | super(context); 55 | } 56 | 57 | public void setScrollSpeed(float scrollSpeed) { 58 | this.milliSecondsPerInch = scrollSpeed; 59 | } 60 | 61 | /** 62 | * Controls the direction in which smoothScroll looks for a list item. 63 | * Use our custom LinearLayoutManager to calculate PointF. 64 | * 65 | * @param targetPosition 66 | * 67 | * @return PointF, a class holding two float coordinates 68 | */ 69 | @Override 70 | public PointF computeScrollVectorForPosition(int targetPosition) { 71 | return CenterLayoutManager.this.computeScrollVectorForPosition(targetPosition); 72 | } 73 | 74 | @Override 75 | public int calculateDtToFit(int viewStart, int viewEnd, int boxStart, int boxEnd, int snapPreference) { 76 | switch (anchor) { 77 | case SnappingRecyclerView.START: 78 | return super.calculateDtToFit(viewStart, viewEnd, boxStart, boxEnd, SNAP_TO_START); 79 | case SnappingRecyclerView.END: 80 | return super.calculateDtToFit(viewStart, viewEnd, boxStart, boxEnd, SNAP_TO_END); 81 | case SnappingRecyclerView.CENTER: 82 | default: 83 | return ((boxStart + boxEnd) / 2) - ((viewStart + viewEnd) / 2); 84 | } 85 | } 86 | 87 | protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) { 88 | return (milliSecondsPerInch > 0 ? milliSecondsPerInch : MILLISECONDS_PER_INCH) / displayMetrics.densityDpi; 89 | } 90 | } 91 | 92 | } 93 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/main/java/com/dant/centersnapreyclerview/SnappingRecyclerView.java: -------------------------------------------------------------------------------- 1 | package com.dant.centersnapreyclerview; 2 | 3 | import android.content.Context; 4 | import android.content.res.TypedArray; 5 | import android.support.annotation.IntDef; 6 | import android.support.annotation.Nullable; 7 | import android.support.v7.widget.LinearLayoutManager; 8 | import android.support.v7.widget.RecyclerView; 9 | import android.util.AttributeSet; 10 | import android.view.View; 11 | 12 | import java.lang.annotation.Retention; 13 | import java.lang.annotation.RetentionPolicy; 14 | import java.lang.ref.WeakReference; 15 | 16 | /** 17 | * An extension of RecyclerView which provides the ability for an anchor to which views will snap 18 | * too. Once a scroll has been completed the RecyclerView will calculate which of it's Views 19 | * (ViewHolders) is closest to it's anchor and, using the smoothScroll method provided by 20 | * CenterLayoutManager, scroll said View to the correct position on screen. 21 | */ 22 | public class SnappingRecyclerView extends RecyclerView { 23 | 24 | @IntDef({HORIZONTAL, VERTICAL}) 25 | @Retention(RetentionPolicy.SOURCE) 26 | public @interface OrientationMode {} 27 | 28 | public static final int VERTICAL = 0; 29 | public static final int HORIZONTAL = 1; 30 | 31 | @IntDef({CENTER, START, END}) 32 | @Retention(RetentionPolicy.SOURCE) 33 | public @interface AnchorMode {} 34 | 35 | public static final int CENTER = 0; 36 | public static final int START = 1; 37 | public static final int END = 2; 38 | 39 | private static final int DEFAULT_FLING_THRESHOLD = 1000; 40 | 41 | public interface SnappingRecyclerViewListener { 42 | void onPositionChange(int position); 43 | void onScroll(int dx, int dy); 44 | } 45 | 46 | private WeakReference listener; 47 | 48 | private int orientation; 49 | 50 | /** 51 | * The anchor to which a View (ViewHolder) should snap too, the START, CENTER or END 52 | */ 53 | private int anchor; 54 | 55 | /** 56 | * The smooth scroll speed, in ms per inch, this is 100 by default in our custom smooth 57 | * scroller 58 | */ 59 | private float scrollSpeed; 60 | 61 | /** 62 | * If the velocity of the user's fling is below a set threshold, finish fling and scroll to the 63 | * appropriate View 64 | */ 65 | private int flingThreshold; 66 | 67 | private CenterLayoutManager layoutManager; 68 | 69 | public SnappingRecyclerView(Context context) { 70 | super(context); 71 | initialise(context, null); 72 | } 73 | 74 | public SnappingRecyclerView(Context context, @Nullable AttributeSet attrs) { 75 | super(context, attrs); 76 | initialise(context, attrs); 77 | } 78 | 79 | public SnappingRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) { 80 | super(context, attrs, defStyle); 81 | initialise(context, attrs); 82 | } 83 | 84 | private void initialise(Context context, @Nullable AttributeSet attrs) { 85 | TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.SnappingRecyclerView, 0, 0); 86 | try { 87 | orientation = a.getInt(R.styleable.SnappingRecyclerView_orientation, VERTICAL); 88 | anchor = a.getInt(R.styleable.SnappingRecyclerView_anchor, CENTER); 89 | scrollSpeed = a.getFloat(R.styleable.SnappingRecyclerView_scrollSpeed, -1); 90 | flingThreshold = a.getInt(R.styleable.SnappingRecyclerView_flingThreshold, DEFAULT_FLING_THRESHOLD); 91 | } finally { 92 | a.recycle(); 93 | } 94 | 95 | layoutManager = new CenterLayoutManager(getContext()); 96 | layoutManager.setOrientation(orientation == VERTICAL ? LinearLayoutManager.VERTICAL : LinearLayoutManager.HORIZONTAL); 97 | layoutManager.setAnchor(anchor); 98 | layoutManager.setScrollSpeed(scrollSpeed); 99 | setLayoutManager(layoutManager); 100 | } 101 | 102 | public SnappingRecyclerViewListener getListener() { 103 | return listener != null ? listener.get() : null; 104 | } 105 | 106 | public void setListener(SnappingRecyclerViewListener listener) { 107 | this.listener = new WeakReference<>(listener); 108 | } 109 | 110 | public void setOrientation(@OrientationMode int orientation) { 111 | if (this.orientation != orientation) { 112 | this.orientation = orientation; 113 | 114 | layoutManager.setOrientation(orientation == VERTICAL ? LinearLayoutManager.VERTICAL : LinearLayoutManager.HORIZONTAL); 115 | requestLayout(); 116 | } 117 | } 118 | 119 | @OrientationMode 120 | public int getOrientation() { 121 | return orientation; 122 | } 123 | 124 | public void setAnchor(@AnchorMode int anchor) { 125 | if (this.anchor != anchor) { 126 | this.anchor = anchor; 127 | 128 | layoutManager.setAnchor(anchor); 129 | requestLayout(); 130 | } 131 | } 132 | 133 | @AnchorMode 134 | public int getAnchor() { 135 | return anchor; 136 | } 137 | 138 | @Override 139 | public void onScrolled(int dx, int dy) { 140 | super.onScrolled(dx, dy); 141 | 142 | if(getListener() != null) { 143 | getListener().onScroll(dx, dy); 144 | } 145 | } 146 | 147 | @Override 148 | public void scrollToPosition(final int position) { 149 | super.scrollToPosition(position); 150 | 151 | // Use the smoothScroll provided by the CenterLayoutManager 152 | post(new Runnable() { 153 | @Override 154 | public void run() { 155 | smoothScrollToPosition(position); 156 | } 157 | }); 158 | } 159 | 160 | @Override 161 | public boolean fling(int velocityX, int velocityY) { 162 | if(Math.abs(orientation == VERTICAL ? velocityY : velocityX) < flingThreshold) { 163 | int centerViewPosition = calculateSnapViewPosition(); 164 | smoothScrollToPosition(centerViewPosition); 165 | 166 | if(getListener() != null) { 167 | getListener().onPositionChange(centerViewPosition); 168 | } 169 | 170 | return true; 171 | } else { 172 | return super.fling(velocityX, velocityY); 173 | } 174 | } 175 | 176 | @Override 177 | public void onScrollStateChanged(int state) { 178 | super.onScrollStateChanged(state); 179 | 180 | /* Once a scroll has been completed smooth scroll to the nearest View based on the anchor */ 181 | if (state == SCROLL_STATE_IDLE) { 182 | int centerViewPosition = calculateSnapViewPosition(); 183 | smoothScrollToPosition(centerViewPosition); 184 | 185 | if(getListener() != null) { 186 | getListener().onPositionChange(centerViewPosition); 187 | } 188 | } 189 | } 190 | 191 | /** 192 | * Provides the anchor of the parent, the RecyclerView, based on the provided orientation and 193 | * anchor mode 194 | * 195 | * @param orientation The orientation of the RecyclerView, VERTICAL or HORIZONTAL 196 | * @param anchor The RecyclerView's anchor mode, START, CENTER or END 197 | * 198 | * @return The anchor of the parent, the RecyclerView 199 | */ 200 | private int getParentAnchor(@OrientationMode int orientation, @AnchorMode int anchor) { 201 | switch (anchor) { 202 | case START: 203 | return 0; 204 | case END: 205 | return orientation == VERTICAL ? getHeight() : getWidth(); 206 | case CENTER: 207 | default: 208 | return (orientation == VERTICAL ? getHeight() : getWidth()) / 2; 209 | } 210 | } 211 | 212 | /** 213 | * Provides the anchor or the given view relative to the provided orientation and anchor. 214 | * This will be the View's start (top or left), center, or end (bottom or right). 215 | * 216 | * @param view 217 | * @param orientation The orientation of the RecyclerView, VERTICAL or HORIZONTAL 218 | * @param anchor The RecyclerView's anchor mode, START, CENTER or END 219 | * 220 | * @return The anchor of the given View relative to the provided orientation and anchor 221 | */ 222 | private int getViewAnchor(View view, @OrientationMode int orientation, @AnchorMode int anchor) { 223 | switch (anchor) { 224 | case START: 225 | return orientation == VERTICAL ? view.getTop() : view.getLeft(); 226 | case END: 227 | return orientation == VERTICAL ? view.getBottom() : view.getRight(); 228 | case CENTER: 229 | default: 230 | return (orientation == VERTICAL ? view.getTop() + (view.getHeight() / 2) : view.getLeft() + (view.getWidth() / 2)); 231 | } 232 | } 233 | 234 | /** 235 | * Calculates the distance between the RecyclerView's anchor, either the start, center or end, 236 | * and the View which is closest to the anchor. 237 | * 238 | * @return The distance between RecyclerView anchor and View closest to anchor 239 | */ 240 | private int calculateSnapDistance() { 241 | LinearLayoutManager linearLayoutManager = (LinearLayoutManager) getLayoutManager(); 242 | 243 | int parentAnchor = getParentAnchor(orientation, anchor); 244 | 245 | int lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition(); 246 | int firstVisibleItemPosition = linearLayoutManager.findFirstVisibleItemPosition(); 247 | 248 | View currentViewClosestToAnchor = linearLayoutManager.findViewByPosition(firstVisibleItemPosition); 249 | 250 | int currentViewClosestToAnchorDistance = parentAnchor - getViewAnchor(currentViewClosestToAnchor, orientation, anchor); 251 | 252 | for(int i = firstVisibleItemPosition + 1; i <= lastVisibleItemPosition; i++) { 253 | View view = linearLayoutManager.findViewByPosition(i); 254 | int distanceToAnchor = parentAnchor - getViewAnchor(view, orientation, anchor); 255 | 256 | if (Math.abs(distanceToAnchor) < Math.abs(currentViewClosestToAnchorDistance)) { 257 | currentViewClosestToAnchorDistance = distanceToAnchor; 258 | } 259 | } 260 | 261 | return currentViewClosestToAnchorDistance; 262 | } 263 | 264 | /** 265 | * Finds the position of the View which is closest to the RecyclerView's anchor, either the 266 | * RecyclerView's start, center or end 267 | * 268 | * @return The position of the View closest the to RecyclerView's anchor 269 | */ 270 | private int calculateSnapViewPosition() { 271 | LinearLayoutManager linearLayoutManager = (LinearLayoutManager) getLayoutManager(); 272 | 273 | int parentAnchor = getParentAnchor(orientation, anchor); 274 | 275 | int lastVisibleItemPosition = linearLayoutManager.findLastVisibleItemPosition(); 276 | int firstVisibleItemPosition = linearLayoutManager.findFirstVisibleItemPosition(); 277 | 278 | View currentViewClosestToAnchor = linearLayoutManager.findViewByPosition(firstVisibleItemPosition); 279 | 280 | int currentViewClosestToAnchorDistance = parentAnchor - getViewAnchor(currentViewClosestToAnchor, orientation, anchor); 281 | 282 | int currentViewClosestToAnchorPosition = firstVisibleItemPosition; 283 | 284 | for(int i = firstVisibleItemPosition + 1; i <= lastVisibleItemPosition; i++) { 285 | View view = linearLayoutManager.findViewByPosition(i); 286 | 287 | int distanceToCenter = parentAnchor - getViewAnchor(view, orientation, anchor); 288 | 289 | if (Math.abs(distanceToCenter) < Math.abs(currentViewClosestToAnchorDistance)) { 290 | currentViewClosestToAnchorPosition = i; 291 | currentViewClosestToAnchorDistance = distanceToCenter; 292 | } 293 | } 294 | 295 | return currentViewClosestToAnchorPosition; 296 | } 297 | } 298 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/main/res/values/snapping_recyclerview.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/main/res/values/strings.xml: -------------------------------------------------------------------------------- 1 | 2 | Snappy ReyclerView 3 | 4 | -------------------------------------------------------------------------------- /snappy-recyclerview/src/test/java/com/dant/centersnapreyclerview/ExampleUnitTest.java: -------------------------------------------------------------------------------- 1 | package com.dant.centersnapreyclerview; 2 | 3 | import org.junit.Test; 4 | 5 | import static org.junit.Assert.*; 6 | 7 | /** 8 | * Example local unit test, which will execute on the development machine (host). 9 | * 10 | * @see Testing documentation 11 | */ 12 | public class ExampleUnitTest { 13 | @Test 14 | public void addition_isCorrect() throws Exception { 15 | assertEquals(4, 2 + 2); 16 | } 17 | } --------------------------------------------------------------------------------