任何人都知道如何将触摸监听器附加到这个类？

Question

package com.ewebapps;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;

public class Dot extends View {
     private final float x;
     private final float y;
     private final int r;
     private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
     private final Paint mWhite = new Paint(Paint.ANTI_ALIAS_FLAG);

     public Dot(Context context, float x, float y, int r) {
         super(context);
         mPaint.setColor(0xFF000000); //Black
         mWhite.setColor(0xFFFFFFFF); //White
         this.x = x;
         this.y = y;
         this.r = r;
     }

     @Override
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);
         canvas.drawCircle(x, y, r+2, mWhite); //White stroke.
         canvas.drawCircle(x, y, r, mPaint); //Black circle.
     }

}

Answer 1

嗯...创建自己的视图时，最好的方法是覆盖dispatchTouchEvent 方法。相信我，使用setOnTouchListener 和onTouchEvent 在某些情况下效果不佳。这就是您在View 中要做的所有事情：

@Override
public boolean dispatchTouchEvent(MotionEvent event) {
    // put your logic here  

    return super.dispatchTouchEvent(event);
}

Answer 2

documentation with example

View aView = (View)findViewById(R.id.DotView);
aView.setOnTouchListener(this);

Full Example Here

Answer 3

Aaron Saunders 的回答适用于视图（如按钮），因为 onTouchListener 只告诉您点击了哪个视图，而不是确切的位置。如果您需要在不创建按钮的情况下准确了解事件的位置，请在您的活动类中尝试以下操作：

@Override onTouchEvent(MotionEvent event) { int _x = event.getX();
int _y = event.getY(); // do stuff }

注意：onTouchEvent 仅在事件未被视图处理时调用。
Documentation

(谁能告诉我如何添加换行符？)