Android：获取设备的mac地址可靠的方法

/**
	 * 获得装备的mac地址
	 * 
	 * @param ac
	 * @param callback
	 *            胜利获得到mac地址以后会回调此办法
	 */
	public static void getMacAddress(final Activity ac, final SimpleCallback callback) {
		final WifiManager wm = (WifiManager) ac .getSystemService(Service.WIFI_SERVICE);

		// 如果本次开机后打开过WIFI，则能够直接获得到mac信息。立刻返回数据。
		WifiInfo info = wm.getConnectionInfo();
		if (info != null && info.getMacAddress() != null) {
			if (callback != null) {
				callback.onComplete(info.getMacAddress());
			}
			return;
		}

		// 尝试打开WIFI，并获得mac地址
		if (!wm.isWifiEnabled()) {
			wm.setWifiEnabled(true);
		}

		new Thread(new Runnable() {
			@Override
			public void run() {
				int tryCount = 0;
				final int MAX_COUNT = 10;

				while (tryCount < MAX_COUNT) {
					final WifiInfo info = wm.getConnectionInfo();
					if (info != null && info.getMacAddress() != null) {
						if (callback != null) {
							ac.runOnUiThread(new Runnable() {
								@Override
								public void run() {
									callback.onComplete(info.getMacAddress());
								}
							});
						}
						return;
					}

					SystemClock.sleep(300);
					tryCount++;
				}

				// 未获得到mac地址
				if (callback != null) {
					callback.onComplete(null);
				}
			}
		}).start();
	}/**
	 * 获得装备的mac地址
	 * 
	 * @param ac
	 * @param c