Android画布画圆 android_studio的canvas画圆

1.怎样设置代码

package com.example.rk1130;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Path;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;

/*

自定义view

*/

public class BallView extends View {

private String ball_size;

private float tx=200f;

private float ty=200f;

private Paint paint;

public BallView(Context context) {

super(context);

init();

}

public BallView(Context context, AttributeSet attrs) {

super(context, attrs);

init();

}

public BallView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

init();

}

private void init(){

//设置画笔

paint = new Paint();

//颜色

paint.setColor(Color.BLUE);

//抗锯齿

paint.setAntiAlias(true);

//画笔粗细

paint.setStrokeWidth(2);

//填充

paint.setStyle(Paint.Style.FILL);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

Path path=new Path();

canvas.drawCircle(tx,ty,50,paint);

}

@Override

public boolean onTouchEvent(MotionEvent event) {

//两种方式 一种switch 一种直接写

switch (event.getAction()){

case MotionEvent.ACTION_UP:

tx=event.getX();

ty=event.getY();

break;

case MotionEvent.ACTION_DOWN:

tx=event.getX();

ty=event.getY();

break;

case MotionEvent.ACTION_MOVE:

tx=event.getX();

ty=event.getY();

break;

}

/*tx=event.getX();

ty=event.getY();*/

this.invalidate();

return true;

}

}

2.布局

android:layout_width="wrap_content"

android:layout_height="wrap_content"

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