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

@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……

其他回答

你不需要复杂的计算。 这可以通过使用来自GestureDetector类的OnGestureListener接口来完成。

在onFling方法中,你可以像这样检测所有四个方向:

MyGestureListener.java:

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

public class MyGestureListener implements GestureDetector.OnGestureListener{

    private static final long VELOCITY_THRESHOLD = 3000;

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

    @Override
    public void onShowPress(final MotionEvent e){ }

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

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

    @Override
    public void onLongPress(final MotionEvent e){ }

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

        if(Math.abs(velocityX) < VELOCITY_THRESHOLD 
                    && Math.abs(velocityY) < VELOCITY_THRESHOLD){
            return false;//if the fling is not fast enough then it's just like drag
        }

        //if velocity in X direction is higher than velocity in Y direction,
        //then the fling is horizontal, else->vertical
        if(Math.abs(velocityX) > Math.abs(velocityY)){
            if(velocityX >= 0){
                Log.i("TAG", "swipe right");
            }else{//if velocityX is negative, then it's towards left
                Log.i("TAG", "swipe left");
            }
        }else{
            if(velocityY >= 0){
                Log.i("TAG", "swipe down");
            }else{
                Log.i("TAG", "swipe up");
            }
        }

        return true;
    }
}

用法:

GestureDetector mDetector = new GestureDetector(MainActivity.this, new MyGestureListener());

view.setOnTouchListener(new View.OnTouchListener(){
    @Override
    public boolean onTouch(final View v, final MotionEvent event){
        return mDetector.onTouchEvent(event);
    }
});

使用SwipeListView,让它为你处理手势检测。

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。

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

/**
 * Detects left and right swipes across a view.
 */
class OnSwipeTouchListener(context: Context, onSwipeCallBack: OnSwipeCallBack?) : OnTouchListener {

    private var gestureDetector : GestureDetector
    private var onSwipeCallBack: OnSwipeCallBack?=null

    init {

        gestureDetector = GestureDetector(context, GestureListener())
        this.onSwipeCallBack = onSwipeCallBack!!
    }
    companion object {

        private val SWIPE_DISTANCE_THRESHOLD = 100
        private val SWIPE_VELOCITY_THRESHOLD = 100
    }

   /* fun onSwipeLeft() {}

    fun onSwipeRight() {}*/

    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(eve1: MotionEvent?, eve2: MotionEvent?, velocityX: Float, velocityY: Float): Boolean {
            try {
                if(eve1 != null&& eve2!= null) {
                    val distanceX = eve2?.x - eve1?.x
                    val distanceY = eve2?.y - eve1?.y
                    if (Math.abs(distanceX) > Math.abs(distanceY) && Math.abs(distanceX) > SWIPE_DISTANCE_THRESHOLD && Math.abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                        if (distanceX > 0)
                            onSwipeCallBack!!.onSwipeLeftCallback()
                        else
                            onSwipeCallBack!!.onSwipeRightCallback()
                        return true
                    }
                }
            }catch (exception:Exception){
                exception.printStackTrace()
            }

            return false
        }


    }
}

这个问题很多年前就有人问过了。现在,有一个更好的解决方案:SmartSwipe: https://github.com/luckybilly/SmartSwipe

代码如下所示:

SmartSwipe.wrap(contentView)
        .addConsumer(new StayConsumer()) //contentView stay while swiping with StayConsumer
        .enableAllDirections() //enable directions as needed
        .addListener(new SimpleSwipeListener() {
            @Override
            public void onSwipeOpened(SmartSwipeWrapper wrapper, SwipeConsumer consumer, int direction) {
                //direction: 
                //  1: left
                //  2: right
                //  4: top
                //  8: bottom
            }
        })
;