Android 手势介绍

     //如果不在主线程中创建,则需要 Looper.prepare(),因为内部的创建Handler()用于数据传输需要 Loop,也可以传一个Handler进去，Handler(Looper.getMainLooper())
        gestureDetector = GestureDetector(this, object : GestureDetector.SimpleOnGestureListener() {
            // OnContextClickListener
            override fun onContextClick(e: MotionEvent?): Boolean {
                // 监听外部设备按钮
                Log.d("Gesture", "onContextClick")
                return super.onContextClick(e)
            }

            //OnDoubleTapListener
            override fun onSingleTapConfirmed(e: MotionEvent?): Boolean {
                //当发生双击时不会触发,两次点击在300ms(ViewConfiguration.DOUBLE_TAP_TIMEOUT)之内 ，通过   Handler().sendEmptyMessageDelayed()实现
                Log.d("Gesture", "onSingleTapConfirmed")
                return super.onSingleTapConfirmed(e)
            }

            override fun onDoubleTap(e: MotionEvent?): Boolean {
                //当第二次 action 为 "0-down"的时候就触发此方法
                Log.d("Gesture", "onDoubleTap")
                return super.onDoubleTap(e)
            }

            override fun onDoubleTapEvent(e: MotionEvent): Boolean {
                //二次点击的Action 变化时会触发，如果要在 action 为"1-up"的时候处理，就在这个方法里实现逻辑
                Log.d("Gesture", "onDoubleTapEvent - ${e.action}")
                return super.onDoubleTapEvent(e)
            }


            //OnGestureListener
            override fun onDown(e: MotionEvent?): Boolean {
                //按下
                Log.d("Gesture", "onDown")
                return super.onDown(e)
            }

            override fun onShowPress(e: MotionEvent?) {
                //延时回调 100(ViewConfiguration.TAP_TIMEOUT)后还是处于 action "0-down"就会触发
                Log.d("Gesture", "onShowPress")
                super.onShowPress(e)
            }

            override fun onSingleTapUp(e: MotionEvent?): Boolean {
                //双击时，onDoubleTapUp会触发，onSingleTapUp会在第一次"down"时触发
                Log.d("Gesture", "onSingleTapUp")
                return super.onSingleTapUp(e)
            }

            override fun onScroll(e1: MotionEvent?, e2: MotionEvent?, distanceX: Float, distanceY: Float): Boolean {
                //快速滑动
                Log.d("Gesture", "onScroll")
                return super.onScroll(e1, e2, distanceX, distanceY)
            }

            override fun onLongPress(e: MotionEvent?) {
                //长按 500(ViewConfiguration.DEFAULT_LONG_PRESS_TIMEOUT)后还是处于 action "0-down"就会触发
                Log.d("Gesture", "onLongPress")
                super.onLongPress(e)
            }

            override fun onFling(e1: MotionEvent?, e2: MotionEvent?, velocityX: Float, velocityY: Float): Boolean {
                //快速滑动后抬起
                Log.d("Gesture", "onFling")
                return super.onFling(e1, e2, velocityX, velocityY)
            }
        })

• GestureDetector

  1. 构造方法，实际上调用的都是

  GestureDetector(Context context, OnGestureListener listener, Handler handler)

  其中handler 一般可以不传，类内部会自行创建。Handler用于处理数据需要Looper。如果不在主线程中创建
  GestureDetector，则在之前执行Looper.prepare()或需传Handler(Looper.getMainLooper()

  2. 监听器

  • OnContextClickListener

    API:23, detector.onGenericMotionEvent(MotionEvent)

    name	description
    onContextClick	监听外部设备按钮

  • OnDoubleTapListener

  detector.onTouchEvent(MotionEvent)

  name	description
  onSingleTapConfirmed	当发生双击时不会触发;延时回调，两次点击在300ms(ViewConfiguration.DOUBLE_TAP_TIMEOUT)之内 ，Handler().sendEmptyMessageDelayed()
  onDoubleTap	当第二次(300ms之内) action 为 "0-down"的时候就触发此方法
  onDoubleTapEvent	二次点击的Action 变化时会触发，如果要在 action 为"1-up"的时候处理，就在这个方法里实现逻辑

  • OnGestureListener

  detector.onTouchEvent(MotionEvent)

  name	description
  onDown	按下
  onShowPress	触摸, 延时回调 100(ViewConfiguration.TAP_TIMEOUT)后还是处于 action "0-down"就会触发,Handler().sendEmptyMessageAtTime()
  onSingleTapUp	单击时触发, 双击时onDoubleTapUp会触发,此时onSingleTapUp会在第一次"down"时触发,第二次不触发
  onScroll	滑动
  onLongPress	长按 500(ViewConfiguration.DEFAULT_LONG_PRESS_TIMEOUT)后还是处于 action "0-down"就会触发,Handler().sendEmptyMessageAtTime()
  onFling	快速滑动后抬起

• ScaleGestureDetector

     private var preScale: Float = 1.0F
     private var curScale: Float = 1.0F
     scaleGestureDetector = ScaleGestureDetector(this, object : ScaleGestureDetector.SimpleOnScaleGestureListener() {
  
         override fun onScaleBegin(detector: ScaleGestureDetector): Boolean {
             Log.d(
                 "ScaleGesture",
                 "onScaleBegin: scaleFactor-${detector.scaleFactor} focusX-${detector.focusX} focusY-${detector.focusY}"
             )
             return true
         }
  
         override fun onScale(detector: ScaleGestureDetector): Boolean {
  
             //保证连续性，不处理的话有明显的抖动
             curScale = detector.scaleFactor * preScale
             if (curScale > 5 || curScale < 0.1) {
                 curScale = preScale
                 return true
             }
             testV.scaleY = curScale
             testV.scaleX = curScale
             preScale = curScale
             Log.d(
                 "ScaleGesture",
                 "onScale: scaleFactor-${detector.scaleFactor} focusX-${detector.focusX} focusY-${detector.focusY}"
             )
             return super.onScale(detector)
         }
  
         override fun onScaleEnd(detector: ScaleGestureDetector) {
             Log.d(
                 "ScaleGesture",
                 "onScaleEnd: scaleFactor-${detector.scaleFactor} focusX-${detector.focusX} focusY-${detector.focusY}"
             )
         }
     })
  
  

  1. 构造方法

  ScaleGestureDetector(Context context, OnScaleGestureListener listener, Handler handler)

  同GestureDetector

  2. 监听器
  • OnScaleGestureListener

  name	description
  onScaleBegin	缩放手势开始，返回false时,不使用此次缩放手势,继续回调onScaleBegin();返回true 则回调 onScale()
  onScale	触发缩放，返回false,继续回调onScale();返回true,回调onScaleEnd(),这次缩放结束
  onScaleEnd	缩放结束，在onScale()中返回为true, 或有手指抬起时，触发此方法

资源

例子

Android开发艺术探索 - 任玉刚