Recyclerview本身没有自动滚动的方法以及这种效果

那么我们首先想到的就是自定义View

创建一个用来写自定义View的类

public class MYScrView extends RecyclerView {private Autoaaview autoview;private boolean running;private boolean canrun;private static final int Timea = 16;public MYScrView(@NonNull Context context, @Nullable AttributeSet attrs) {super(context, attrs);autoview = new Autoaaview(this);}public MYScrView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}private class Autoaaview implements Runnable{WeakReference<MYScrView> myScrViewWeakReference;public Autoaaview(MYScrView myScrView) {myScrViewWeakReference = new WeakReference<>(myScrView);}@Overridepublic void run() {MYScrView myScrView = myScrViewWeakReference.get();// myScrView!=null&&if (myScrView.canrun&&myScrView.running){myScrView.scrollBy(2,2);myScrView.postDelayed(myScrView.autoview,Timea);}}}public void stort(){if (running)stop();running = true;canrun = true;postDelayed(autoview,Timea);}private void stop() {running = false;removeCallbacks(autoview);}@Overridepublic boolean onTouchEvent(MotionEvent e) {switch (e.getAction()){case MotionEvent.ACTION_DOWN:if (running){stop();}break;case MotionEvent.ACTION_UP:case MotionEvent.ACTION_CANCEL:case MotionEvent.ACTION_OUTSIDE:if (canrun){stort();}break;}return super.onTouchEvent(e);}}

XML

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><com.example.myappli01.MYScrViewandroid:layout_width="wrap_content"android:id="@+id/Myscr"android:layout_height="300dp"/><LinearLayoutandroid:layout_width="match_parent"android:layout_alignParentBottom="true"android:layout_height="56dp"><EditTextandroid:layout_width="300dp"android:layout_height="match_parent"android:id="@+id/pl"android:background="@color/colorPrimary"/><Buttonandroid:layout_width="wrap_content"android:id="@+id/send"android:layout_height="wrap_content"android:text="发送"/></LinearLayout></RelativeLayout>

RecyclerView 用来给Adapter传送的item

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical" android:layout_width="match_parent"android:layout_height="wrap_content"><TextViewandroid:layout_width="match_parent"android:layout_height="wrap_content"android:gravity="center"android:textSize="24dp"android:id="@+id/textaaa"/></LinearLayout>

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这是在Activity里面写的

//Activity里面的点击事件的方法private void send() {//发送的点击事件send.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {//运用Dialog再次判断 正常情况下是不需要判断的，自己灵活运用AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);builder.setTitle("发送");builder.setMessage("是否发送");builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialogInterface, int i) {String trim = pl.getText().toString().trim();if (trim.equals("")) {Toast.makeText(MainActivity.this, "不允许为空", Toast.LENGTH_SHORT).show();} else {strings.add(new My(trim));addDanmaku(trim,true);if (myscrviewAdapter == null) {myscrviewAdapter = new MyscrviewAdapter(MainActivity.this, strings);Myscr.setAdapter(myscrviewAdapter);Myscr.setLayoutManager(new LinearLayoutManager(MainActivity.this));if (true)Myscr.stort();} else {myscrviewAdapter.notifyDataSetChanged();}}}});builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {@Overridepublic void onClick(DialogInterface dialogInterface, int i) {}});builder.show();}});}

上文中的Adapter 的适配器

public class MyscrviewAdapter extends RecyclerView.Adapter<BaseViewHolder> {Context context;ArrayList<My> mies;public MyscrviewAdapter(Context context, ArrayList<My> mies) {this.context = context;this.mies = mies;}@NonNull@Overridepublic BaseViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {View inflate = LayoutInflater.from(context).inflate(R.layout.string, parent,false);BaseViewHolder baseViewHolder = new BaseViewHolder(inflate);return baseViewHolder;}@Overridepublic void onBindViewHolder(@NonNull BaseViewHolder holder, int position) {holder.setText(R.id.textaaa,mies.get(position%mies.size()).getString()+"");}@Overridepublic int getItemCount() {return Integer.MAX_VALUE;}}

My的小写bean类

public class My {String string;public My() {}public My(String string) {this.string = string;}public String getString() {return string;}public void setString(String string) {this.string = string;}}

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maven { url "https://jitpack.io" }implementation 'androidx.recyclerview:recyclerview:1.0.0'implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:2.9.22'