我们先来看看效果

继承RecyclerView.OnScrollListener重写onScrolled方法，同时定义两个抽象方法供我们处理隐藏和显示事件

public abstract class HidingScrollListener extends RecyclerView.OnScrollListener {

private static final int HIDE_THRESHOLD = 20;

private int scrolledDistance = 0;

private boolean controlsVisible = true;

@Override

public void onScrolled(RecyclerView recyclerView, int dx, int dy) {

super.onScrolled(recyclerView, dx, dy);

if (scrolledDistance > HIDE_THRESHOLD && controlsVisible) {

onHide();

controlsVisible = false;

scrolledDistance = 0;

}

else if (scrolledDistance < -HIDE_THRESHOLD && !controlsVisible) {

onShow();

controlsVisible = true;

scrolledDistance = 0;

}

if ((controlsVisible && dy > 0) || (!controlsVisible && dy < 0)) {

scrolledDistance += dy;

}

}

public abstract void onHide();

public abstract void onShow();

}

事件的处理

recyclerView.addOnScrollListener(new HidingScrollListener() {

@Override

public void onHide() {

Resources resources = MainActivity.this.getResources();

DisplayMetrics dm = resources.getDisplayMetrics();

float density = dm.density;

int width = dm.widthPixels;

int height = dm.heightPixels;

fab.animate()

.translationY(height - fab.getHeight())

.setInterpolator(new AccelerateInterpolator(2))

.start();

buttom.animate()

.translationY(height - buttom.getHeight())

.setInterpolator(new AccelerateInterpolator(2))

.setDuration(800)

.start();

top.animate()

.translationY(-height)

.setDuration(800)

.setInterpolator(new AccelerateInterpolator(2))

.start();

}

@Override

public void onShow() {

fab.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2)).start();

buttom.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2)).setDuration(800).start();

top.animate().translationY(0).setInterpolator(new DecelerateInterpolator(2)).setDuration(800).start();

}

});

布局文件

xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

android:layout_width="match_parent"

android:layout_height="match_parent"

>

android:id="@+id/recyclerview"

android:layout_width="match_parent"

android:clipToPadding="false"

android:paddingTop="?attr/actionBarSize"

android:layout_height="match_parent"/>

android:id="@+id/top"

android:layout_width="match_parent"

android:layout_height="52dp"

android:background="#f00"

android:orientation="vertical">

android:id="@+id/buttom"

android:layout_width="match_parent"

android:layout_height="52dp"

android:layout_gravity="bottom"

android:background="#f00"

android:orientation="vertical">

android:id="@+id/fab"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="bottom|right"

android:layout_marginBottom="40dp"

app:borderWidth="0dp"

/>