onfling方法，会判断手势从按下到抬起移动的过程，在此方法中进行切换activity等操作。

private int verticalMinDistance = 20;
private int minVelocity = 0;

private GestureDetector mGestureDetector;

rightRelative.setOnTouchListener(this);
mGestureDetector = new GestureDetector(this, this);

@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
    mGestureDetector.onTouchEvent(motionEvent);
    return true;
}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {

    if (e1.getX() - e2.getX() > verticalMinDistance && Math.abs(velocityX) > minVelocity) {
        Intent intent = new Intent(MainActivity.this, HistoryActivity.class);
        startActivity(intent);
        overridePendingTransition(R.anim.unzoom_out, R.anim.unzoom_in);
    } else if (e2.getX() - e1.getX() > verticalMinDistance && Math.abs(velocityX) > minVelocity) {
        Toast.makeText(this, "向右", Toast.LENGTH_SHORT).show();
    }
    return false;

}