绘制一个时钟

public class MyView extends View {
	Paint paint = new Paint();// 画笔
	int height = 0;// 高
	int width = 0;// 宽
	int radius = 0;// 圆心
	Canvas canvas;// 画布

	public MyView(Context context, AttributeSet attrs) {
		super(context, attrs);
		// TODO Auto-generated constructor stub
	}

	@Override
	protected void onDraw(Canvas c) {
		// TODO Auto-generated method stub
		canvas = c;// 赋值，无所谓的操作，方便查看而已
		super.onDraw(canvas);
		width = canvas.getWidth() / 2;// 获取半径宽
		height = canvas.getHeight() / 2;// 获取半径高
		radius = height - 3;// 获取半径
		paint.setColor(Color.BLACK);// 设置画笔颜色
		paint.setStyle(Style.STROKE);// 设置画笔风格
		paint.setStrokeWidth(3);// 设置画笔粗细
		paint.setAntiAlias(true);// 设置抗锯齿
		// 绘制外圆
		canvas.drawCircle(width, height, radius, paint);
		// 循环绘制小刻度（分钟\秒）
		for (int i = 0; i < 60; i++) {
			canvas.save();
			canvas.rotate(i * 6, width, height);
			canvas.drawLine(width, height - radius, width,
					height - radius + 10, paint);
			canvas.restore();
		}
		// 循环绘制大刻度（小时）
		for (int i = 0; i < 12; i++) {
			canvas.save();
			canvas.rotate(i * 30, width, height);
			canvas.drawLine(width, height - radius, width,
					height - radius + 20, paint);
			canvas.restore();
		}
		// 循环绘制时间文本（1-12）
		for (int i = 1; i < 13; i++) {
			paint.setStrokeWidth(1);
			canvas.save();
			canvas.rotate(i * 30, width, height);
			canvas.drawText(String.valueOf(i), width - 5, height - radius + 40,
					paint);
			canvas.restore();
		}
		// 获取系统时间
		Calendar calendar = Calendar.getInstance();
		int hour = calendar.get(Calendar.HOUR);// 小时
		int min = calendar.get(Calendar.MINUTE);// 分钟
		int sec = calendar.get(Calendar.SECOND);// 秒
		// 设置画笔粗细
		paint.setStrokeWidth(15);
		// 设置画笔风格
		paint.setStyle(Style.FILL);
		/**
		 * 绘制指针 ↓
		 */
		// 绘制时针
		canvas.save();// 保存画布
		canvas.rotate(hour * 30 + min / 60 * 30, width, height);
		canvas.drawLine(width, height, width, height - 40, paint);
		// 绘制分针
		paint.setStrokeWidth(10);// 设置画笔粗细
		canvas.rotate(min * 6, width, height);
		canvas.drawLine(width, height, width, height - 50, paint);
		// 绘制秒针
		paint.setStrokeWidth(5);// 设置画笔粗细
		canvas.rotate(sec * 6, width, height);
		canvas.drawLine(width, height, width, height - 60, paint);
		canvas.restore();// 重置画布
		/**
		 * 绘制指针 ↑
		 */
		// 绘制小圆心
		canvas.drawCircle(width, height, 15, paint);
		// 重载View
		invalidate();
	}
}