android 学习：多矩形碰撞检测

public class RectCollision {
	/**
	 * @return true 相交
	 */
	public static boolean isCollision(Rect[] rectArray, Rect[] rect2Array) {
		for (Rect r1 : rectArray) {
			for (Rect r2 : rect2Array) {
				if (isCollision(r1, r2))
					return true;
			}
		}
		return false;
	}
	/**
	 * r1在r2的上面，下面，左面，右面
	 * r1和r2相交
	 * @param r1
	 * @param r2
	 * @return	true 相交
	 */
	public static boolean isCollision(Rect r1, Rect r2) {
		int x1 = r1.left;
		int y1 = r1.top;
		int w1 = r1.right - r1.left;
		int h1 = r1.bottom - r1.top;
		
		int x2 = r2.left;
		int y2 = r2.top;
		int w2 = r2.right - r2.left;
		int h2 = r2.bottom - r2.top;
		
		if (y1+h1 < y2 /*上*/ || x1+w1 < x2 /*左*/ 
			|| y2+h2 < y1 /*下*/	|| x2+w2 < x1 /*右*/) {
			return false;
		}
		return true;
	}
}