android - 难以实现手势控制

Question

我正在尝试学习 Android 应用程序中的手势检测。但显然，在使用 onFling 方法时，我在 logcat 中什么也得不到。我在主类上实现了 GestureDetector.OnGestureListener。我从这里看到了手势检测的例子: https://developer.android.com/training/gestures/detector.html#detect

package com.persi.fragmenttester;
import android.content.Intent;
import android.support.v4.view.GestureDetectorCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;

public class MainActivity extends AppCompatActivity implements GestureDetector.OnGestureListener,
        GestureDetector.OnDoubleTapListener{

    private GestureDetectorCompat mDetector;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDetector=new GestureDetectorCompat(this,this);
        mDetector.setOnDoubleTapListener(this);


    }


    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onDoubleTap(MotionEvent e) {
        Log.d("App",e.toString());
        return true;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onDown(MotionEvent e) {
        return false;
    }

    @Override
    public void onShowPress(MotionEvent e) {

    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        return false;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        return false;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        Log.d("App",e.toString());

    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        Log.d("App", "onFling: " + e1.toString() + e2.toString());
        return true;

    }
}

Answer 1

你需要覆盖onTouchEvent()

@Override
public boolean onTouchEvent(MotionEvent event){
    if (this.mDetector.onTouchEvent(event)) {
        return true;
    }
    return super.onTouchEvent(event);
}

来自文档:

To make it possible for your GestureDetector object to receive events, you override the View or Activity's onTouchEvent() method, and pass along all observed events to the detector instance.