手势，Kotlin Android Studio

Question

我在 Android Studio、Kotlin 中制作计算器。我希望在交换期间按下数学运算符按钮，但它们不起作用

在MainActivity.kt中：

    private lateinit var lSwipeDetector: GestureDetectorCompat
    private lateinit var mainLayout: LinearLayout

    private var lastX: Float = 0.0f
    private var lastY: Float = 0.0f
    private var lastZ: Float = 0.0f
    companion object {
        private const val SWIPE_MIN_DISTANCE = 130
        private const val SWIPE_MAX_DISTANCE = 300
        private const val SWIPE_MIN_VELOCITY = 200
    }

在onCreate fun中：

        mainLayout = findViewById(R.id.main_layout)

        lSwipeDetector = GestureDetectorCompat(this, MyGestureListener())

        mainLayout.setOnTouchListener { _, event ->
            lSwipeDetector.onTouchEvent(event)
            true
        }

然后我在MainActivity中为gesters进程创建了内部类

inner class MyGestureListener : GestureDetector.SimpleOnGestureListener() {
        override fun onDown(e: MotionEvent): Boolean {
            return true
        }

        override fun onFling(
            e1: MotionEvent?,
            e2: MotionEvent,
            velocityX: Float,
            velocityY: Float
        ): Boolean {
            val deltaX = e2.x - e1!!.x
            val deltaY = e2.y - e1.y
            val deltaXAbs = abs(deltaX)
            val deltaYAbs = abs(deltaY)

            if (deltaXAbs > SWIPE_MIN_DISTANCE && abs(velocityX) > SWIPE_MIN_VELOCITY) {
                if (deltaX > 0) {
                    bPlus.performClick()
                    //Toast.makeText(this@MainActivity, "Swipe Right", Toast.LENGTH_SHORT).show()
                } else {
                    bMin.performClick()
                    //Toast.makeText(this@MainActivity, "Swipe Left", Toast.LENGTH_SHORT).show()
                }
                return true
            }

            if (deltaYAbs > SWIPE_MIN_DISTANCE && abs(velocityY) > SWIPE_MIN_VELOCITY) {
                if (deltaY > 0) {
                    bDiv.performClick()
                    //Toast.makeText(this@MainActivity, "Swipe Down", Toast.LENGTH_SHORT).show()
                } else {
                    bMul.performClick()
                    //Toast.makeText(this@MainActivity, "Swipe Up", Toast.LENGTH_SHORT).show()
                }
                return true
            }

            return false
        }
    }

我的活动_主要：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="10"
    android:background="@drawable/background"
    tools:context=".MainActivity">

...

从调试来看，交换不涉及 MyGestureListener 类，甚至不涉及 mainLayout

Answer 1

活动类中缺少 onTouchEvent 方法

class MainActivity: AppCompatActivity(), GestureDetector.OnGestureListener {
  private lateinit var gestureDetector: GestureDetectorCompat

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        gestureDetector = GestureDetectorCompat(this, this)
    }

    override fun onTouchEvent(event: MotionEvent): Boolean {
        gestureDetector.onTouchEvent(event)
        return super.onTouchEvent(event)
    }

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

    override fun onShowPress(e: MotionEvent) {
    }

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

    override fun onScroll(
        e1: MotionEvent?,
        e2: MotionEvent,
        distanceX: Float,
        distanceY: Float,
    ): Boolean {
        return true
    }

    override fun onLongPress(e: MotionEvent) {
    }

    override fun onFling(
        maine1: MotionEvent?,
        e2: MotionEvent,
        velocityX: Float,
        velocityY: Float,
    ): Boolean {
        maine1?.let { e1 ->
            val diffX = e2.x - e1.x
            val diffY = e2.y - e1.y

            if (abs(diffX) > abs(diffY)) {
                if (abs(diffX) > SWIPE_THRESHOLD && abs(velocityX) > SWIPE_VELOCITY_THRESHOLD) {
                    if (diffX > 0) {
                        Toast.makeText(this@MainActivity, "Swipe Right", Toast.LENGTH_SHORT).show()
                    } else {
                        Toast.makeText(this@MainActivity, "Swipe Left", Toast.LENGTH_SHORT).show()
                    }
                    return true
                }
            } else {
                if (abs(diffY) > SWIPE_THRESHOLD && abs(velocityY) > SWIPE_VELOCITY_THRESHOLD) {
                    if (diffY > 0) {
                        Toast.makeText(this@MainActivity, "Swipe Down", Toast.LENGTH_SHORT).show()
                    } else {
                        Toast.makeText(this@MainActivity, "Swipe Up", Toast.LENGTH_SHORT).show()
                    }
                    return true
                }
            }
        }
        return false
    }
}