继承View绘制正方形且360旋转

 1 import android.content.Context;
 2 import android.graphics.Canvas;
 3 import android.graphics.Color;
 4 import android.graphics.Paint;
 5 import android.util.AttributeSet;
 6 import android.view.View;
 7
 8 public class RotatingRect extends View {
 9
11     private Paint p;             // 画笔
12     private float degrees = 0;   // 旋转角度
13
14     public RotatingRect(Context context, AttributeSet attrs, int defStyleAttr) {
15         super(context, attrs, defStyleAttr);
16
17         initProperties();
18     }
19
20     public RotatingRect(Context context, AttributeSet attrs) {
21         super(context, attrs);
22
23         initProperties();
24     }
25
26     public RotatingRect(Context context) {
27         super(context);
28
29         initProperties();
30     }
31
33     private void initProperties(){
34         p = new Paint();
35         p.setColor(Color.RED);
36     }
37
39     @Override
40     public void draw(Canvas canvas) {
41         super.draw(canvas);
42
43         canvas.save();
44        //  canvas.rotate(degrees);
45         // 调整坐标
46         canvas.translate(200, 200);
47         // 设置，绕着中心点旋转
48         canvas.rotate(degrees, 50, 50);
49         canvas.drawRect(0, 0, 100, 100, p);
51         degrees ++;
52         canvas.restore();
53
54         invalidate();
55     }
57 }