占百分比，扇形图

public class MyView extends View {
Paint p1 = new Paint();
Paint p2 = new Paint();
Paint p3 = new Paint();
Paint p4 = new Paint();
RectF rectF1 = new RectF(0,0,600,600);
RectF rectF2 = new RectF(250,250,350,350);
RectF rectF3 = new RectF(100,100,500,500);
float i=0,j=3;
boolean flag = true;
boolean flag1 = true;
public MyView(Context context) {
super(context);
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void draw(Canvas canvas) {
super.draw(canvas);
MyThread myThread = new MyThread();
p1.setColor(Color.parseColor("#dddddd"));
p1.setAntiAlias(true);
p2.setColor(Color.parseColor("#cc0000"));
p2.setAntiAlias(true);
p3.setColor(Color.parseColor("#dddddd"));
p3.setAntiAlias(true);
p4.setColor(Color.parseColor("#000000"));
p4.setAntiAlias(true);
canvas.drawArc(rectF1, 0f, 360f, true, p1);
canvas.drawArc(rectF3, 0f, i, true, p2);
myThread.start();

canvas.drawArc(rectF3, 100f, j, true, p4);
new Thread(new Runnable() {
@Override
public void run() {
while (flag1)
{
j++;
if(j>=90)
{
flag1 = false;
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
postInvalidate();
}
}
}).start();
canvas.drawArc(rectF2, 0f, 360f, true, p3);
}
class MyThread extends Thread{
public void run() {
super.run();
while (flag) {
i++;
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
postInvalidate();
if(i>=90)
{
flag = false;
}
}
}
}
}