04工具类判断网络是否可用的方法和全局Constant类

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;
	}

}

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";
	
}