android 检查网络

 public static boolean isNetworkConnected(Context context) {ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo network = cm.getActiveNetworkInfo();if (network != null) {    return network.isAvailable();}return false;    }

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/><!-- 检查网络 -->