Android仿小红书图片自动滚动效果

public class MainActivity extends AppCompatActivity {
    private RecyclerView mRecyclerView;
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);
        //全屏        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_main);
        mRecyclerView = findViewById(R.id.mRecyclerView);        mRecyclerView.setAdapter(new SplashAdapter(MainActivity.this));        mRecyclerView.setLayoutManager(new ScollLinearLayoutManager(MainActivity.this));
        //smoothScrollToPosition滚动到某个位置（有滚动效果）        mRecyclerView.smoothScrollToPosition(Integer.MAX_VALUE / 2);    }}

public class SplashAdapter extends RecyclerView.Adapter<SplashAdapter.ViewHolder> {
    private int imgWidth;

    public SplashAdapter(Context context) {        imgWidth = EasyUtil.getScreenWidth(context);    }
    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_splash, parent, false);        return new ViewHolder(itemView);    }
    @Override    public void onBindViewHolder(final ViewHolder holder, final int position) {       /* ViewGroup.LayoutParams lp = holder.item_bg.getLayoutParams();        lp.width = imgWidth;        lp.height =imgWidth*5;        holder.item_bg.setLayoutParams(lp);*/    }
    @Override    public int getItemCount() {        return Integer.MAX_VALUE;    }
    public class ViewHolder extends RecyclerView.ViewHolder {
        ImageView item_bg;
        public ViewHolder(final View itemView) {            super(itemView);            item_bg = itemView.findViewById(R.id.item_bg);        }    }}

/** * 更改RecyclerView滚动的速度 */public class ScollLinearLayoutManager extends LinearLayoutManager {    private float MILLISECONDS_PER_INCH = 25f;  //修改可以改变数据,越大速度越慢    private Context contxt;
    public ScollLinearLayoutManager(Context context) {        super(context);        this.contxt = context;    }

    @Override    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {        LinearSmoothScroller linearSmoothScroller =                new LinearSmoothScroller(recyclerView.getContext()) {                    @Override                    public PointF computeScrollVectorForPosition(int targetPosition) {                        return ScollLinearLayoutManager.this                                .computeScrollVectorForPosition(targetPosition);                    }
                    @Override                    protected float calculateSpeedPerPixel                            (DisplayMetrics displayMetrics) {                        return MILLISECONDS_PER_INCH / displayMetrics.density;                        //返回滑动一个pixel需要多少毫秒                    }
                };        linearSmoothScroller.setTargetPosition(position);        startSmoothScroll(linearSmoothScroller);    }
    //可以用来设置速度    public void setSpeedSlow(float x) {        //自己在这里用density去乘，希望不同分辨率设备上滑动速度相同        //0.3f是自己估摸的一个值，可以根据不同需求自己修改        MILLISECONDS_PER_INCH = contxt.getResources().getDisplayMetrics().density * 0.3f + (x);    }
}

@SuppressLint("AppCompatCustomView")public class FitImageView extends ImageView {
    public FitImageView(Context context) {        super(context);    }
    public FitImageView(Context context, AttributeSet attrs) {        super(context, attrs);    }
    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){        Drawable drawable = getDrawable();
        if(drawable!=null){            int width = MeasureSpec.getSize(widthMeasureSpec);            int height = (int) Math.ceil((float) width * (float) drawable.getIntrinsicHeight() / (float) drawable.getIntrinsicWidth());            setMeasuredDimension(width, height);        }else{            super.onMeasure(widthMeasureSpec, heightMeasureSpec);        }    }}

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content">
    <com.next.scrollimagedemo.view.FitImageView        android:id="@+id/item_bg"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:src="@mipmap/ww1" />

    <!--  <ImageView          android:id="@+id/item_bg"          android:layout_width="match_parent"          android:layout_height="wrap_content"          android:src="@mipmap/ww2"          android:scaleType="centerCrop"/>-->
</android.support.constraint.ConstraintLayout>

<android.support.constraint.ConstraintLayout 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">
    <android.support.v7.widget.RecyclerView        android:id="@+id/mRecyclerView"        android:layout_width="match_parent"        android:layout_height="match_parent"></android.support.v7.widget.RecyclerView>
    <TextView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="#80000000"        android:clickable="true" />
    <ImageView        android:layout_width="wrap_content"        android:layout_height="80dp"        android:layout_marginTop="80dp"        app:layout_constraintTop_toTopOf="parent"        android:scaleType="centerInside"        android:src="@mipmap/slogan"        app:layout_constraintLeft_toLeftOf="parent"        app:layout_constraintRight_toRightOf="parent" />
</android.support.constraint.ConstraintLayout>