import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

public class DrawViewextendsView {

public float currentX=40; 

public float currentY=50;

Paint p=new Paint();

public DrawView(Contextcontext) {

super(context);

}

public DrawView(Contextcontext, AttributeSet set){

super(context, set);

}

@Override

public voidonDraw(Canvas canvas){

super.onDraw(canvas);

p.setColor(Color.GREEN);

canvas.drawCircle(currentX,currentY,15,p);

}

@Override

public booleanonTouchEvent(MotionEvent event){

currentX = event.getX();

currentY= event.getY();

invalidate();

return true;

}

}

网页版简书好难用。