GestureDetector手勢識別

MainActivity :

public class MainActivity extends Activity {

    GestureDetector myGestureDetector;
    ImageView iv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iv = (ImageView) findViewById(R.id.iv);
        myGestureDetector = new GestureDetector(new myGestureLister());
        iv.setOnTouchListener(new OnTouchListener() {

            @Override
            public boolean onTouch(View v, MotionEvent event) {
                myGestureDetector.onTouchEvent(event);
                return true;
            }
        });
    }

    class myGestureLister extends SimpleOnGestureListener {
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                float velocityY) {
            if ((e1.getX() - e2.getX()) > 50) {
                Toast.makeText(MainActivity.this, "從右向左滑動", Toast.LENGTH_LONG)
                        .show();
            } else if ((e2.getX() - e1.getX()) > 50) {
                Toast.makeText(MainActivity.this, "從左向右滑動", Toast.LENGTH_LONG)
                        .show();
            }
            return super.onFling(e1, e2, velocityX, velocityY);
        }
    }

}

佈局：

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

    <ImageView
        android:id="@+id/iv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#555"/>

</RelativeLayout>