Android自定义View画圆功能

 public class ViView extends View{ Paint paint; Context context; //构造方法 public ViView(Context context) { super(context); } public ViView(Context context, AttributeSet attrs) { super(context, attrs); } public ViView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } public ViView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); this.context=context; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); } /*绘图*/ @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //得到屏幕宽高 int width = getWidth(); int radius = width - 450/2; int height = getHeight(); // 创建画笔 Paint paint1 = new Paint(); Paint paint2 = new Paint(); Paint paint3= new Paint(); // 消除锯齿 paint1.setAntiAlias(true); paint2.setAntiAlias(true); paint3.setAntiAlias(true); //画笔颜色 paint1.setColor(Color.RED); paint2.setColor(Color.WHITE); paint3.setColor(Color.BLUE); // 画圆。确定位置 // canvas.drawRect(100,100,width/2,height/2,paint1); // canvas.drawCircle(100,100,100,paint1); // canvas.drawCircle(250,250,200,paint2); // canvas.drawCircle(500,500,300,paint3); //设置圆环形状和大小 RectF oval = new RectF(width-radius,width-radius,width+radius,width+radius); paint1.setStrokeWidth(450); canvas.drawArc(oval,-90,90,false,paint1); canvas.drawCircle(width/2,height/2,450,paint1); canvas.drawCircle(width/2,height/2,300,paint2); canvas.drawCircle(width/2,height/2,200,paint3); } @Override public boolean onTouchEvent(MotionEvent event) { return super.onTouchEvent(event); } }