在Kotlin中放大/缩小滚动视图

Question

首先，我使用下面的网站作为参考，并直接放大表格。但是这里没有任何错误，但是没有用。 https://developer.android.com/training/gestures/scale#kotlin

之后，我尝试在scrollview中制定可缩放的时间表。但是同样的问题又发生了。

注意： 时间表中有一个片段，所以我使用了2个setContentView。

class MainActivity : AppCompatActivity() {

private lateinit var mScaleDetector: ScaleGestureDetector
private var scaleFactor = 1.0f
private lateinit var table : ScrollView
lateinit var gestureDetector :GestureDetector


override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.fragment_week_timetable)

    gestureDetector = GestureDetector(this, GestureListener())
    mScaleDetector = ScaleGestureDetector(this, ScaleGestureDetector.SimpleOnScaleGestureListener())
    table = findViewById<ScrollView>(R.id.scrollView2)
    mScaleDetector = ScaleGestureDetector(this, ScaleListener())
    setContentView(R.layout.activity_main)

}

override fun dispatchTouchEvent(ev: MotionEvent?): Boolean {
    super.dispatchTouchEvent(ev)
    mScaleDetector.onTouchEvent(ev)
    gestureDetector.onTouchEvent(ev)
    return gestureDetector.onTouchEvent(ev)
}

private inner class ScaleListener : ScaleGestureDetector.SimpleOnScaleGestureListener() {
    override fun onScale(scaleGestureDetector: ScaleGestureDetector): Boolean {

        scaleFactor *= scaleGestureDetector.scaleFactor
        scaleFactor = max(0.1f, min(scaleFactor, 10.0f))
        table.scaleX = scaleFactor
        table.scaleY = scaleFactor
        return true
    }
}

private class GestureListener : GestureDetector.SimpleOnGestureListener() {
    override fun onDown(e: MotionEvent): Boolean {
        return true
    }
    override fun onDoubleTap(e: MotionEvent): Boolean {
        return true;
    }
}