Android使用PhotoView实现图片双击放大单击退出效果

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/activity_main"
  android:layout_width="match_parent"
  android:layout_height="match_parent">


  <uk.co.senab.photoview.PhotoView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/pv"
    android:src="@drawable/ic_emptya"/>
</RelativeLayout>

public class MainActivity extends AppCompatActivity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    PhotoView pv = (PhotoView) findViewById(R.id.pv);
    pv.setOnPhotoTapListener(new PhotoViewAttacher.OnPhotoTapListener() {
      @Override
      public void onPhotoTap(View view, float v, float v1) {
        finish();
      }
    });
  }
}