├── .gitignore ├── .idea ├── caches │ └── build_file_checksums.ser ├── codeStyles │ └── Project.xml ├── dictionaries │ └── andy.xml ├── encodings.xml ├── gradle.xml ├── misc.xml ├── runConfigurations.xml └── vcs.xml ├── README.md ├── app ├── .gitignore ├── build.gradle ├── proguard-rules.pro └── src │ ├── androidTest │ └── java │ │ └── com │ │ └── jennifer │ │ └── andy │ │ └── recyclerscrolltoposition │ │ └── ExampleInstrumentedTest.java │ ├── main │ ├── AndroidManifest.xml │ ├── java │ │ └── com │ │ │ └── jennifer │ │ │ └── andy │ │ │ └── simple │ │ │ ├── MainActivity.java │ │ │ ├── SimpleTextAdapter.java │ │ │ └── widget │ │ │ ├── AdjustLinearLayoutManager.java │ │ │ └── AdjustLinearSmoothScroller.java │ └── res │ │ ├── drawable-v24 │ │ └── ic_launcher_foreground.xml │ │ ├── drawable │ │ └── ic_launcher_background.xml │ │ ├── layout │ │ ├── activity_main.xml │ │ └── item_simple_text.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 │ └── com │ └── jennifer │ └── andy │ └── recyclerscrolltoposition │ └── ExampleUnitTest.java ├── build.gradle ├── gradle.properties ├── gradle └── wrapper │ ├── gradle-wrapper.jar │ └── gradle-wrapper.properties ├── gradlew ├── gradlew.bat └── settings.gradle /.gitignore: -------------------------------------------------------------------------------- 1 | *.iml 2 | .gradle 3 | /local.properties 4 | /.idea/libraries 5 | /.idea/modules.xml 6 | /.idea/workspace.xml 7 | .DS_Store 8 | /build 9 | /captures 10 | .externalNativeBuild 11 | -------------------------------------------------------------------------------- /.idea/caches/build_file_checksums.ser: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/AndyJennifer/RecyclerScrollToPosition/560a920d75d6190959a9e76b8794b5755bcd3288/.idea/caches/build_file_checksums.ser -------------------------------------------------------------------------------- /.idea/codeStyles/Project.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 |
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109 | 110 | 111 | 112 | 113 | -------------------------------------------------------------------------------- /.idea/dictionaries/andy.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | -------------------------------------------------------------------------------- /.idea/encodings.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | -------------------------------------------------------------------------------- /.idea/gradle.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 20 | 21 | -------------------------------------------------------------------------------- /.idea/misc.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 24 | 41 | 42 | 43 | 44 | 45 | 46 | 48 | 49 | 51 | -------------------------------------------------------------------------------- /.idea/runConfigurations.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 11 | 12 | -------------------------------------------------------------------------------- /.idea/vcs.xml: -------------------------------------------------------------------------------- 1 | 2 | 3 | 4 | 5 | 6 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | 2 | # RecyclerScrollToPosition 3 | 4 | RecyclerScrollToPosition 是一个控制 RecyclerView Item的滚动位置及滚动速度的项目。该项目主要包含如下内容 5 | 6 | - 当调用 RecyclerView.smoothScrollToPosition(position)后，使该 position 下的 item 置顶显示 7 | - 当调用 RecyclerView.smoothScrollToPosition(position)后，使该 position 下的 item 置底显示 8 | - 控制 RecyclerView 的滚动速度。 9 | 10 | ## 项目展示 💤 11 | 12 | 13 | 14 | ## 更多 👏 15 | 16 | 如果你想了解其中的原理，你可以阅读以下两篇文章， 17 | 18 | - [RecyclerView.smoothScrollToPosition了解一下](https://juejin.im/post/5b305656f265da59921a1025) 19 | - [RecyclerView滚动位置，滚动速度设置](https://juejin.im/post/5b3056a051882574a54da8e6) 20 | 21 | ## 最后 🤖 22 | 23 | 如果你觉得项目不错，欢迎点击 star ❤️ follow，也可以帮忙分享给你更多的朋友。你的支持与鼓励是给我继续做好该项目的最大动力。 24 | 25 | ## 联系我 🤙 26 | 27 | - QQ:443696320 28 | - 简书：[AndyandJennifer](https://www.jianshu.com/users/921c778fb5e1/timeline) 29 | - 掘金：[AndyandJennifer](https://juejin.im/user/5acc1ea06fb9a028bc2e0fc1) 30 | - Email：[andyjennifer@126.com](andyjennifer@126.com) 31 | -------------------------------------------------------------------------------- /app/.gitignore: -------------------------------------------------------------------------------- 1 | /build 2 | -------------------------------------------------------------------------------- /app/build.gradle: -------------------------------------------------------------------------------- 1 | apply plugin: 'com.android.application' 2 | 3 | android { 4 | compileSdkVersion 27 5 | defaultConfig { 6 | applicationId "com.jennifer.andy.recyclerscrolltoposition" 7 | minSdkVersion 19 8 | targetSdkVersion 27 9 | versionCode 1 10 | versionName "1.0" 11 | testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" 12 | } 13 | buildTypes { 14 | release { 15 | minifyEnabled false 16 | proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' 17 | } 18 | } 19 | } 20 | 21 | dependencies { 22 | implementation fileTree(dir: 'libs', include: ['*.jar']) 23 | implementation 'com.android.support:appcompat-v7:27.1.1' 24 | implementation 'com.android.support:recyclerview-v7:27.1.1' 25 | implementation 'com.android.support.constraint:constraint-layout:1.1.2' 26 | testImplementation 'junit:junit:4.12' 27 | androidTestImplementation 'com.android.support.test:runner:1.0.2' 28 | androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2' 29 | } 30 | -------------------------------------------------------------------------------- /app/proguard-rules.pro: -------------------------------------------------------------------------------- 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 | -------------------------------------------------------------------------------- /app/src/androidTest/java/com/jennifer/andy/recyclerscrolltoposition/ExampleInstrumentedTest.java: -------------------------------------------------------------------------------- 1 | package com.jennifer.andy.recyclerscrolltoposition; 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 | * Instrumented 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() { 21 | // Context of the app under test. 22 | Context appContext = InstrumentationRegistry.getTargetContext(); 23 | 24 | assertEquals("com.jennifer.andy.recyclerscrolltoposition", appContext.getPackageName()); 25 | } 26 | } 27 | -------------------------------------------------------------------------------- /app/src/main/AndroidManifest.xml: -------------------------------------------------------------------------------- 1 | 2 | 4 | 5 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | -------------------------------------------------------------------------------- /app/src/main/java/com/jennifer/andy/simple/MainActivity.java: -------------------------------------------------------------------------------- 1 | package com.jennifer.andy.simple; 2 | 3 | import android.os.Bundle; 4 | import android.support.v7.app.AppCompatActivity; 5 | import android.support.v7.widget.DividerItemDecoration; 6 | import android.support.v7.widget.LinearSmoothScroller; 7 | import android.support.v7.widget.RecyclerView; 8 | import android.view.View; 9 | import android.widget.Button; 10 | import android.widget.RadioGroup; 11 | import android.widget.SeekBar; 12 | import android.widget.TextView; 13 | import android.widget.Toast; 14 | 15 | import com.jennifer.andy.simple.widget.AdjustLinearLayoutManager; 16 | import com.jennifer.andy.simple.widget.AdjustLinearSmoothScroller; 17 | 18 | import java.util.ArrayList; 19 | import java.util.List; 20 | 21 | public class MainActivity extends AppCompatActivity { 22 | 23 | 24 | private RecyclerView mRecyclerView; 25 | private RadioGroup mRadioGroup; 26 | private SeekBar mSeekPosition; 27 | private SeekBar mSeekTime; 28 | private TextView mTvInchTime; 29 | private TextView mTvPosition; 30 | private Button mBtnStart; 31 | 32 | private List mStringList; 33 | private AdjustLinearLayoutManager mLayoutManager; 34 | private int mScrollType = LinearSmoothScroller.SNAP_TO_ANY; 35 | 36 | @Override 37 | protected void onCreate(Bundle savedInstanceState) { 38 | super.onCreate(savedInstanceState); 39 | setContentView(R.layout.activity_main); 40 | findView(); 41 | initData(); 42 | } 43 | 44 | private void findView() { 45 | 46 | mRecyclerView = findViewById(R.id.recycler); 47 | mRadioGroup = findViewById(R.id.radio_group); 48 | mSeekPosition = findViewById(R.id.sb_position); 49 | mSeekTime = findViewById(R.id.seek_bar); 50 | mTvInchTime = findViewById(R.id.tv_time); 51 | mTvPosition = findViewById(R.id.tv_position); 52 | mBtnStart = findViewById(R.id.btn_start); 53 | 54 | mRadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { 55 | @Override 56 | public void onCheckedChanged(RadioGroup group, int checkedId) { 57 | mLayoutManager = new AdjustLinearLayoutManager(MainActivity.this); 58 | switch (checkedId) { 59 | case R.id.rb_normal://default 60 | mScrollType = LinearSmoothScroller.SNAP_TO_ANY; 61 | break; 62 | case R.id.rb_top://top 63 | mScrollType = LinearSmoothScroller.SNAP_TO_START; 64 | break; 65 | case R.id.rb_bottom://bottom 66 | mScrollType = LinearSmoothScroller.SNAP_TO_END; 67 | break; 68 | 69 | } 70 | mLayoutManager.setScrollType(mScrollType); 71 | mRecyclerView.setLayoutManager(mLayoutManager); 72 | mRecyclerView.setAdapter(new SimpleTextAdapter(MainActivity.this, mStringList)); 73 | mRecyclerView.addItemDecoration(new DividerItemDecoration(MainActivity.this, DividerItemDecoration.VERTICAL)); 74 | } 75 | }); 76 | 77 | mSeekPosition.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { 78 | @Override 79 | public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 80 | mTvPosition.setText(getString(R.string.to_position, progress)); 81 | } 82 | 83 | @Override 84 | public void onStartTrackingTouch(SeekBar seekBar) { 85 | 86 | } 87 | 88 | @Override 89 | public void onStopTrackingTouch(SeekBar seekBar) { 90 | 91 | } 92 | }); 93 | 94 | mSeekTime.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { 95 | @Override 96 | public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 97 | mLayoutManager.setMillisecondsPerInch(progress); 98 | mTvInchTime.setText(getString(R.string.ms_per_inch, progress)); 99 | } 100 | 101 | @Override 102 | public void onStartTrackingTouch(SeekBar seekBar) { 103 | 104 | } 105 | 106 | @Override 107 | public void onStopTrackingTouch(SeekBar seekBar) { 108 | 109 | } 110 | }); 111 | 112 | mBtnStart.setOnClickListener(new View.OnClickListener() { 113 | @Override 114 | public void onClick(View v) { 115 | int position = mSeekPosition.getProgress(); 116 | int perInchTime = mSeekTime.getProgress(); 117 | if (position <= 0) { 118 | Toast.makeText(MainActivity.this, "Position cannot be zero", Toast.LENGTH_SHORT).show(); 119 | } else if (perInchTime <= 10) { 120 | Toast.makeText(MainActivity.this, "Time cannot be less than ten milliseconds", Toast.LENGTH_SHORT).show(); 121 | } else { 122 | mRecyclerView.smoothScrollToPosition(position); 123 | } 124 | } 125 | }); 126 | 127 | 128 | } 129 | 130 | 131 | private void initData() { 132 | mStringList = new ArrayList<>(); 133 | for (int i = 0; i < 100; i++) { 134 | mStringList.add("this is data " + i); 135 | } 136 | mLayoutManager = new AdjustLinearLayoutManager(this); 137 | mLayoutManager.setScrollType(mScrollType); 138 | mRecyclerView.setLayoutManager(mLayoutManager); 139 | mRecyclerView.setAdapter(new SimpleTextAdapter(this, mStringList)); 140 | mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL)); 141 | 142 | mSeekPosition.setMax(mStringList.size()); 143 | mSeekTime.setProgress((int) AdjustLinearSmoothScroller.DEFAULT_MILLISECONDS_PER_INCH); 144 | mTvPosition.setText(getString(R.string.to_position, 0)); 145 | } 146 | 147 | } 148 | -------------------------------------------------------------------------------- /app/src/main/java/com/jennifer/andy/simple/SimpleTextAdapter.java: -------------------------------------------------------------------------------- 1 | package com.jennifer.andy.simple; 2 | 3 | import android.content.Context; 4 | import android.support.annotation.NonNull; 5 | import android.support.v7.widget.RecyclerView; 6 | import android.view.LayoutInflater; 7 | import android.view.View; 8 | import android.view.ViewGroup; 9 | import android.widget.TextView; 10 | 11 | import java.util.List; 12 | 13 | /** 14 | * Author: andy.xwt 15 | * Date: 2018/6/20 15:49 16 | * Description: 17 | */ 18 | 19 | public class SimpleTextAdapter extends RecyclerView.Adapter { 20 | 21 | private List list; 22 | private Context mContext; 23 | 24 | public SimpleTextAdapter(Context context, List list) { 25 | this.mContext = context; 26 | this.list = list; 27 | 28 | } 29 | 30 | @NonNull 31 | @Override 32 | public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) { 33 | return new SimpleTextHolder(LayoutInflater.from(mContext).inflate(R.layout.item_simple_text, parent, false)); 34 | } 35 | 36 | @Override 37 | public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) { 38 | SimpleTextHolder textHolder = (SimpleTextHolder) holder; 39 | textHolder.mTextView.setText(list.get(position)); 40 | } 41 | 42 | @Override 43 | public int getItemCount() { 44 | return list.size(); 45 | } 46 | 47 | private static class SimpleTextHolder extends RecyclerView.ViewHolder { 48 | 49 | TextView mTextView; 50 | 51 | SimpleTextHolder(View itemView) { 52 | super(itemView); 53 | mTextView = itemView.findViewById(R.id.tv_text); 54 | } 55 | } 56 | 57 | 58 | } 59 | -------------------------------------------------------------------------------- /app/src/main/java/com/jennifer/andy/simple/widget/AdjustLinearLayoutManager.java: -------------------------------------------------------------------------------- 1 | package com.jennifer.andy.simple.widget; 2 | 3 | import android.content.Context; 4 | import android.support.v7.widget.LinearLayoutManager; 5 | import android.support.v7.widget.RecyclerView; 6 | import android.util.AttributeSet; 7 | 8 | import static com.jennifer.andy.simple.widget.AdjustLinearSmoothScroller.DEFAULT_MILLISECONDS_PER_INCH; 9 | 10 | /** 11 | * Author: andy.xwt 12 | * Date: 2018/6/20 16:28 13 | * Description: 14 | */ 15 | 16 | public class AdjustLinearLayoutManager extends LinearLayoutManager { 17 | 18 | private int scrollType; 19 | private float time = DEFAULT_MILLISECONDS_PER_INCH; 20 | 21 | public AdjustLinearLayoutManager(Context context) { 22 | super(context); 23 | } 24 | 25 | public AdjustLinearLayoutManager(Context context, int orientation, boolean reverseLayout) { 26 | super(context, orientation, reverseLayout); 27 | } 28 | 29 | public AdjustLinearLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 30 | super(context, attrs, defStyleAttr, defStyleRes); 31 | } 32 | 33 | 34 | public void setMillisecondsPerInch(float time) { 35 | this.time = time; 36 | } 37 | 38 | public void setScrollType(@AdjustLinearSmoothScroller.ScrollType int scrollType) { 39 | this.scrollType = scrollType; 40 | } 41 | 42 | @Override 43 | public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) { 44 | AdjustLinearSmoothScroller.setTime(time); 45 | AdjustLinearSmoothScroller scroller = new AdjustLinearSmoothScroller(recyclerView.getContext(), scrollType); 46 | scroller.setTargetPosition(position); 47 | startSmoothScroll(scroller); 48 | } 49 | 50 | } 51 | -------------------------------------------------------------------------------- /app/src/main/java/com/jennifer/andy/simple/widget/AdjustLinearSmoothScroller.java: -------------------------------------------------------------------------------- 1 | package com.jennifer.andy.simple.widget; 2 | 3 | import android.content.Context; 4 | import android.support.annotation.IntDef; 5 | import android.support.v7.widget.LinearSmoothScroller; 6 | import android.util.DisplayMetrics; 7 | 8 | /** 9 | * Author: andy.xwt 10 | * Date: 2020/3/28 18:06 11 | * Description: 12 | */ 13 | 14 | public class AdjustLinearSmoothScroller extends LinearSmoothScroller { 15 | 16 | private int scrollType; 17 | private static float time; 18 | public static final float DEFAULT_MILLISECONDS_PER_INCH = 25f; 19 | 20 | 21 | @IntDef({SNAP_TO_ANY, SNAP_TO_START, SNAP_TO_END}) 22 | public @interface ScrollType { 23 | } 24 | 25 | 26 | public AdjustLinearSmoothScroller(Context context, @ScrollType int scrollType) { 27 | super(context); 28 | this.scrollType = scrollType; 29 | } 30 | 31 | @Override 32 | protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) { 33 | return time / displayMetrics.densityDpi; 34 | } 35 | 36 | public static void setTime(float milliseconds) { 37 | time = milliseconds; 38 | } 39 | 40 | @Override 41 | protected int getVerticalSnapPreference() { 42 | return scrollType; 43 | } 44 | } 45 | -------------------------------------------------------------------------------- /app/src/main/res/drawable-v24/ic_launcher_foreground.xml: -------------------------------------------------------------------------------- 1 | 7 | 12 | 13 | 19 | 22 | 25 | 26 | 27 | 28 | 34 | 35 | -------------------------------------------------------------------------------- /app/src/main/res/drawable/ic_launcher_background.xml: -------------------------------------------------------------------------------- 1 | 2 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | 28 | 30 | 32 | 34 | 36 | 38 | 40 | 42 | 44 | 46 | 48 | 50 | 52 | 54 | 56 | 58 | 60 | 62 | 64 | 66 | 68 | 70 | 72 | 74 | 75 | -------------------------------------------------------------------------------- /app/src/main/res/layout/activity_main.xml: -------------------------------------------------------------------------------- 1 | 2 | 6 | 7 | 8 | 14 | 15 | 21 | 22 | 27 | 28 | 34 | 35 | 40 | 41 | 42 | 48 | 49 | 53 | 54 | 59 | 60 | 68 | 69 | 76 | 77 | 84 | 85 | 86 | 87 | 93 | 94 | 100 | 101 | 107 | 108 | 109 | 110 |