04工具类判断网络是否可用的方法和全局Constant类

判断网络是否可用的方法：

package com.dy.ustc.im.utils;import android.content.Context;import android.net.ConnectivityManager;import android.net.NetworkInfo;/** *  * 工具类 *  *  */public class CommonUtils {public static boolean isNetWorkConnected(Context context) {// 解决空指针异常if (context != null) {ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo networkInfo = mConnectivityManager.getActiveNetworkInfo();if (networkInfo != null) {return networkInfo.isAvailable();}}return false;}}

注意获取网络连接管理器和前面获取包管理器的方式，然后再获取相应的info。

package com.dy.ustc.im;public class Constant {public static final String NEW_FRIENDS_USERNAME = "item_new_friends";public static final String GROUP_USERNAME = "item_groups";public static final String MESSAGE_ATTR_IS_VOICE_CALL = "is_voice_call";}