自定义view圆环的改变

 //次线程更新ui
    Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            invalidate();
            if (du>=360){
                timer.cancel();
            }
        }
    };
    Timer timer = null;
    int outColor = Color.GRAY;
    float du = 0;
    public MyView(Context context) {
        super(context);
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public MyView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onCreateContextMenu(ContextMenu menu) {
        super.onCreateContextMenu(menu);
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //最上面的字
        Paint p1 = new Paint();
        p1.setColor(Color.BLACK);
        p1.setTextSize(32);
        canvas.drawText("改变外层圆环的颜色",0,32,p1);

        //最外面的园
        Paint p2 = new Paint();
        p2.setColor(outColor);
        canvas.drawCircle(getWidth()/2,getHeight()/2,100,p2);

        //进度
        Paint p5 = new Paint();
        p5.setColor(Color.RED);
        RectF rectF = new RectF(getWidth()/2-100,getHeight()/2-100,getWidth()/2+100,getHeight()/2+100);
        canvas.drawArc(rectF,0,du,true,p5);

        //中心的白色园
        Paint p3 = new Paint();
        p3.setColor(Color.WHITE);
        canvas.drawCircle(getWidth()/2,getHeight()/2,50,p3);

        //中间的文字
        Paint p4 = new Paint();
        p4.setColor(Color.BLACK);
        canvas.drawText("78%",getWidth()/2,getHeight()/2,p4);

        //开始
        Paint p6 = new Paint();
        p6.setColor(Color.BLACK);
        p6.setTextSize(32);
        canvas.drawText("开始",0,getHeight()-100,p6);

        //重置
        Paint p7 = new Paint();
        p7.setColor(Color.BLACK);
        p7.setTextSize(32);
        canvas.drawText("重置",getWidth()/2,getHeight()-100,p6);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getAction() == MotionEvent.ACTION_DOWN){
            if (event.getY() <= 32) {//更改上面的文字为绿色
                outColor = Color.GREEN;
                invalidate();
            }
            if (event.getX() < getWidth()/2 && event.getY()<getHeight()-100 && event.getY()>getHeight()-132){
                //Log.d("mylog","开始");
                //点击开始后启动timer不断的给du进行++
                timer = new Timer();
                timer.schedule(new TimerTask() {
                    @Override
                    public void run() {
                        du += 12;
                        Log.d("mylog","度数:"+du);
                        handler.sendEmptyMessage(1);
                    }
                },1000,1000);
            }
            if (event.getX() >= getWidth()/2 && event.getY()<getHeight()-100 && event.getY()>getHeight()-132){
                //Log.d("mylog","重置");
                //重置，把所有的变量回归初始值，更新界面，关闭timer
                du = 0;
                outColor = Color.GRAY;
                invalidate();
                timer.cancel();
            }
        }
        return super.onTouchEvent(event);
    }
}