我希望我的应用程序能够识别用户在手机屏幕上从右向左滑动。

如何做到这一点?


当前回答

@Edward Brey的方法很有效。如果有人也想复制和粘贴导入的OnSwipeTouchListener,他们是:

 import android.content.Context;
 import android.view.GestureDetector;
 import android.view.GestureDetector.SimpleOnGestureListener;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.View.OnTouchListener;

其他回答

@Mirek Rusin的Kotlin版本在这里:

OnSwipeTouchListener。kt:

open class OnSwipeTouchListener(ctx: Context) : OnTouchListener {

    private val gestureDetector: GestureDetector

    companion object {

        private val SWIPE_THRESHOLD = 100
        private val SWIPE_VELOCITY_THRESHOLD = 100
    }

    init {
        gestureDetector = GestureDetector(ctx, GestureListener())
    }

    override fun onTouch(v: View, event: MotionEvent): Boolean {
        return gestureDetector.onTouchEvent(event)
    }

    private inner class GestureListener : SimpleOnGestureListener() {


        override fun onDown(e: MotionEvent): Boolean {
            return true
        }

        override fun onFling(e1: MotionEvent, e2: MotionEvent, velocityX: Float, velocityY: Float): Boolean {
            var result = false
            try {
                val diffY = e2.y - e1.y
                val diffX = e2.x - e1.x
                if (Math.abs(diffX) > Math.abs(diffY)) {
                    if (Math.abs(diffX) > SWIPE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                        if (diffX > 0) {
                            onSwipeRight()
                        } else {
                            onSwipeLeft()
                        }
                        result = true
                    }
                } else if (Math.abs(diffY) > SWIPE_THRESHOLD && Math.abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
                    if (diffY > 0) {
                        onSwipeBottom()
                    } else {
                        onSwipeTop()
                    }
                    result = true
                }
            } catch (exception: Exception) {
                exception.printStackTrace()
            }

            return result
        }


    }

    open fun onSwipeRight() {}

    open fun onSwipeLeft() {}

    open fun onSwipeTop() {}

    open fun onSwipeBottom() {}
}

用法:

view.setOnTouchListener(object : OnSwipeTouchListener(context) {

    override fun onSwipeTop() {
        super.onSwipeTop()
    }

    override fun onSwipeBottom() {
        super.onSwipeBottom()
    }

    override fun onSwipeLeft() {
        super.onSwipeLeft()
    }

    override fun onSwipeRight() {
        super.onSwipeRight()
    }
})

open关键字对我来说很重要……

扩展Mirek的回答,当你想在滚动视图中使用滑动手势时。默认情况下,滚动视图的触摸监听器被禁用,因此滚动动作不会发生。为了解决这个问题,您需要重写Activity的dispatchTouchEvent方法,并在您完成自己的侦听器后返回该方法的继承版本。

为了对Mirek的代码做一些修改: 我在OnSwipeTouchListener中添加了一个gestureDetector getter。

public GestureDetector getGestureDetector(){
    return  gestureDetector;
}

在Activity中声明OnSwipeTouchListener作为类范围的字段。

OnSwipeTouchListener onSwipeTouchListener;

相应修改用法代码:

onSwipeTouchListener = new OnSwipeTouchListener(MyActivity.this) {
    public void onSwipeTop() {
        Toast.makeText(MyActivity.this, "top", Toast.LENGTH_SHORT).show();
    }
    public void onSwipeRight() {
        Toast.makeText(MyActivity.this, "right", Toast.LENGTH_SHORT).show();
    }
    public void onSwipeLeft() {
        Toast.makeText(MyActivity.this, "left", Toast.LENGTH_SHORT).show();
    }
    public void onSwipeBottom() {
        Toast.makeText(MyActivity.this, "bottom", Toast.LENGTH_SHORT).show();
    }
});

imageView.setOnTouchListener(onSwipeTouchListener);

并覆盖活动内部的dispatchTouchEvent方法:

@Override
    public boolean dispatchTouchEvent(MotionEvent ev){
        swipeListener.getGestureDetector().onTouchEvent(ev); 
            return super.dispatchTouchEvent(ev);   
    }

现在滚动和滑动动作都可以工作了。

使用SwipeListView,让它为你处理手势检测。

爱德华·布雷的回答在科特林的使用

 view.setOnTouchListener(object: OnSwipeTouchListener(this) {
      override fun onSwipeLeft() {
        super.onSwipeLeft()
      }
      override fun onSwipeRight() {
        super.onSwipeRight()
      }
    }
 )

这段代码检测左右滑动,避免了废弃的API调用,并对之前的答案进行了其他改进。

/**
 * Detects left and right swipes across a view.
 */
public class OnSwipeTouchListener implements OnTouchListener {

    private final GestureDetector gestureDetector;

    public OnSwipeTouchListener(Context context) {
        gestureDetector = new GestureDetector(context, new GestureListener());
    }

    public void onSwipeLeft() {
    }

    public void onSwipeRight() {
    }

    public boolean onTouch(View v, MotionEvent event) {
        return gestureDetector.onTouchEvent(event);
    }

    private final class GestureListener extends SimpleOnGestureListener {

        private static final int SWIPE_DISTANCE_THRESHOLD = 100;
        private static final int SWIPE_VELOCITY_THRESHOLD = 100;

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

        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
            float distanceX = e2.getX() - e1.getX();
            float distanceY = e2.getY() - e1.getY();
            if (Math.abs(distanceX) > Math.abs(distanceY) && Math.abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                if (distanceX > 0)
                    onSwipeRight();
                else
                    onSwipeLeft();
                return true;
            }
            return false;
        }
    }
}

像这样使用它:

view.setOnTouchListener(new OnSwipeTouchListener(context) {
    @Override
    public void onSwipeLeft() {
        // Whatever
    }
});