如何同时为WebView滑动和触摸事件? [英] How to have both swipe and touch events for WebView?

问题描述

大家好，我正在创建epub阅读器，并且我已经自定义了WebView可以水平滚动，现在我想停止默认滚动并根据滑动的手势以编程方式进行滚动，我已经达到了这种效果

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;
    }

  }
 }

以及我的主要活动

 webView.setOnTouchListener(new OnSwipeTouchListener(this) {
                        @Override
                        public void onSwipeLeft() {
                            // my code to scroll previous page

                            }

                        }
                        @Override
                        public void onSwipeRight() {
                            //my code to scroll next page
                        }
                    });

现在出现了问题，我不能在长按选择文本时使用默认功能WebView，如何进行滑动事件并在长按选择时仍然获得文本选择功能?

解决方案

通过实现onTouch()，将不会调用View的onTouchEvent()方法，从而阻止其运行默认的触摸行为.

更改以下内容:

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

对此:

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

Hello guys i am creating epub reader and i have customised my WebView to scroll horizontal, now i want to stop the default scroll and do scrolling programatically based on swipe guestures i have already acheive it like this way

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;
    }

  }
 }

and in my main activity

 webView.setOnTouchListener(new OnSwipeTouchListener(this) {
                        @Override
                        public void onSwipeLeft() {
                            // my code to scroll previous page

                            }

                        }
                        @Override
                        public void onSwipeRight() {
                            //my code to scroll next page
                        }
                    });

now the problem stated, i cannot have the default feature of WebView on longpress selecting text, how can i have swiping events and still get the text selection feature on long press?

解决方案

By your implementation of onTouch(), the onTouchEvent() method of the View will not be called, preventing its default touch behaviour to run.

Change the following:

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

To this:

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

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