当用户在屏幕上滑动时显示视图

Question

我正在尝试执行向上滑动手势。类似于WhatsApp过滤器。

是否有Android提供此类操作的布局？我尝试添加一个bottomsheet行为，但是在滑动时无法获得类似的平滑动画。实现OnGestureListener是唯一的方法吗？

任何建议都会有所帮助。

谢谢！

Answer 1

这是滑动检测器，您可以根据需要进行更改

import android.util.Log;
import android.view.MotionEvent;
import android.view.View;

public class SwipeDetector implements View.OnTouchListener{

    private int min_distance = 100;
    private float downX, downY, upX, upY;
    private View v;

    private onSwipeEvent swipeEventListener;



    public SwipeDetector(View v){
        this.v=v;
        v.setOnTouchListener(this);
    }

    public void setOnSwipeListener(onSwipeEvent listener)
    {
        try{
            swipeEventListener=listener;
        }
        catch(ClassCastException e)
        {
            Log.e("ClassCastException","please pass SwipeDetector.onSwipeEvent Interface instance",e);
        }
    }


    public void onRightToLeftSwipe(){
        if(swipeEventListener!=null)
            swipeEventListener.SwipeEventDetected(v,SwipeTypeEnum.RIGHT_TO_LEFT);
        else
            Log.e("SwipeDetector error","please pass SwipeDetector.onSwipeEvent Interface instance");
    }

    public void onLeftToRightSwipe(){
        if(swipeEventListener!=null)
            swipeEventListener.SwipeEventDetected(v,SwipeTypeEnum.LEFT_TO_RIGHT);
        else
            Log.e("SwipeDetector error","please pass SwipeDetector.onSwipeEvent Interface instance");
    }

    public void onTopToBottomSwipe(){
        if(swipeEventListener!=null)
            swipeEventListener.SwipeEventDetected(v,SwipeTypeEnum.TOP_TO_BOTTOM);
        else
            Log.e("SwipeDetector error","please pass SwipeDetector.onSwipeEvent Interface instance");
    }

    public void onBottomToTopSwipe(){
        if(swipeEventListener!=null)
            swipeEventListener.SwipeEventDetected(v,SwipeTypeEnum.BOTTOM_TO_TOP);
        else
            Log.e("SwipeDetector error","please pass SwipeDetector.onSwipeEvent Interface instance");
    }

    public boolean onTouch(View v, MotionEvent event) {
        switch(event.getAction()){
        case MotionEvent.ACTION_DOWN: {
            downX = event.getX();
            downY = event.getY();
            return true;
        }
        case MotionEvent.ACTION_UP: {
            upX = event.getX();
            upY = event.getY();

            float deltaX = downX - upX;
            float deltaY = downY - upY;

            //HORIZONTAL SCROLL
            if(Math.abs(deltaX) > Math.abs(deltaY))
            {
                if(Math.abs(deltaX) > min_distance){
                    // left or right
                    if(deltaX < 0) 
                    {
                        this.onLeftToRightSwipe();
                        return true;
                    }
                    if(deltaX > 0) {
                        this.onRightToLeftSwipe();
                        return true; 
                    }
                }
                else {
                    //not long enough swipe...
                    return false; 
                }
            }
            //VERTICAL SCROLL
            else 
            {
                if(Math.abs(deltaY) > min_distance){
                    // top or down
                    if(deltaY < 0) 
                    { this.onTopToBottomSwipe();
                    return true; 
                    }
                    if(deltaY > 0)
                    { this.onBottomToTopSwipe(); 
                    return true;
                    }
                }
                else {
                    //not long enough swipe...
                    return false;
                }
            }

            return true;
        }
        }
        return false;
    }
    public interface onSwipeEvent
    {
        public void SwipeEventDetected(View v, SwipeTypeEnum SwipeType);
    }

    public SwipeDetector setMinDistanceInPixels(int min_distance)
{
    this.min_distance=min_distance;
    return this;
}

    public enum SwipeTypeEnum
    {
        RIGHT_TO_LEFT,LEFT_TO_RIGHT,TOP_TO_BOTTOM,BOTTOM_TO_TOP
    }

}

这是一个使用示例：

filters_container=(RelativeLayout)root.findViewById(R.id.filters_container);
    new SwipeDetector(filters_container).setOnSwipeListener(new SwipeDetector.onSwipeEvent() {
        @Override
        public void SwipeEventDetected(View v, SwipeDetector.SwipeTypeEnum swipeType) {
            if(swipeType==SwipeDetector.SwipeTypeEnum.LEFT_TO_RIGHT)
                getActivity().onBackPressed();
        }
    });