获取触摸坐标相对于自定义ImageView

Question

我实现了自定义ImageView。因为我的图像很大，我使用ScrollView和Horizo​​ntalScrollView来滚动图像。我想在onTouch事件中绘制圆圈，但它不适用于所有情况。当我滚动图像和触发事件时，x，y坐标适用于图像的当前可见扇区（在右上角，例如0x0，但当我滚动somwhere并且在可见顶部角落时，它也将为0x0），但圆形正在绘制根据图像大小。 另一个问题是，应用程序可以用于各种屏幕尺寸。 我知道它xamarin c＃但在原生Android应该是一样的。任何人都知道如何正确绘制/获取坐标？

public class DrawViewInside : ImageView 
{ 

    public static Bitmap bitmapInside; 
    private Paint paint = new Paint(); 
    private Point point = new Point(); 

    private Canvas mCanvas; 
    private static Bitmap mutableBitmap; 
    private Context mContext; 
    public static Bitmap b; 
    public void SetCarId(int id) 
    { 
     carId = id; 
    } 
    public DrawViewInside(Context context, IAttributeSet attrs) : base(context, attrs) 
    { 
     mContext = context; 
     setDefault(drawable); 
    } 

    public void SetBitmap(int drawableId) 
    { 
     setDefault(drawableId); 
     Invalidate(); 
    } 


    protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec) 
    { 
     base.OnMeasure(widthMeasureSpec, heightMeasureSpec); 

     int width = MeasureSpec.GetSize(widthMeasureSpec); 
     int height = width; 

     var metrics = Resources.DisplayMetrics; 
     if (b != null) 
     { 
      SetMeasuredDimension(b.Width, b.Height); 
     } 

    } 


    public async void setDefault(int drawableId) 
    { 


      BitmapFactory.Options options = await GetBitmapOptionsOfImage(drawableId); 
      paint.Color = Color.Red; 
      paint.StrokeWidth = 15; 
      paint.SetStyle(Paint.Style.Stroke); 
      var metrics = Resources.DisplayMetrics; 
      var widthInDp = ConvertPixelsToDp(metrics.WidthPixels); 
      var heightInDp = ConvertPixelsToDp(metrics.HeightPixels); 

      b = BitmapFactory.DecodeResource(Resources, drawableId);esources, drawableId); 
      mutableBitmap = b.Copy(Bitmap.Config.Argb8888, true); 
      mCanvas = new Canvas(mutableBitmap); 
      mCanvas.Save(); 

    } 


    protected override void OnDraw(Canvas canvas) 
    { 
     DrawCircle(canvas); 


    } 
    private void DrawCircle(Canvas canvas) 
    { 
     if (mCanvas == null) 
     { 
      setDefault(drawable); 
     } 
     else 
     { 
      mCanvas.Restore(); 
      mCanvas.DrawCircle(point.x, point.y, 10, paint); 
      mCanvas.Save(); 
      canvas.DrawBitmap(mutableBitmap, 0, 0, paint); 
      bitmapInside = mutableBitmap; 
     } 


    } 

    public override bool OnTouchEvent(MotionEvent e) 
    { 
     switch (e.Action) 
     { 
      case MotionEventActions.Down: 

       break; 

      case MotionEventActions.Up: 
         Activity act = (Activity)mContext; 

         float viewX = e.RawX - this.Left; 
         float viewY = e.RawY - this.Top; 
         point.x = viewX;// e.RawX; 
         point.y = viewY;// e.RawY; 

        break; 
       } 
     Invalidate(); 
     return true; 

    } 

} 
public class Point 
{ 
    public float x, y; 
} 

Answer 1

我找到了解决办法。只需更换

    float viewX = e.RawX - this.Left; 
        float viewY = e.RawY - this.Top; 
        point.x = viewX;// e.RawX; 
        point.y = viewY;// e.RawY; 

与

     float viewX = e.RawX;// - this.Left; 
         float viewY = e.RawY;// - this.Top; 
         int[] viewCoords = new int[2]; 
         this.GetLocationOnScreen(viewCoords); 
         point.x = viewX - viewCoords[0];// e.RawX; 
         point.y = viewY - viewCoords[1];// e.RawY;