Android_NetworkInfo以及判断手机是否联网

描述了当前网络 Mobile和Wifi的状态。

有2个内部类 NetworkInfo.DetailedState(精确的网络状态)和 NetworInfo.State(粗略的网路状态)

Detailed state	Coarse-grained state
IDLE	DISCONNECTED
SCANNING	CONNECTING
CONNECTING	CONNECTING
AUTHENTICATING	CONNECTING
CONNECTED
DISCONNECTING	DISCONNECTING
DISCONNECTED	DISCONNECTED
UN***AILABLE	DISCONNECTED
FAILED	DISCONNECTED

里面几个常用函数

isAvailable() isConnected() getDetailedState() getState() getExtrInfo()

getType() 获取当前网络的类型mobile or Wi-Fi

getTypeName() 获取当前网络的类型名 “WIFI” or “MOBILE”

ConnectivityManager

用于查询网络连接状态，当网络状态发生改变时通知应用。通过调用Context.getSystemService(Context.CONNECTIVITY_SERVICE)。主要功能：

1.
监视网络(Wi-Fi,GPRS,UMTS,etc)的连接

2.
网络状态发生改变时发送广播

3.
网络丢失时尝试转移的别的网络

4.
提供API

主要函数介绍

1.
NetworkInfo getActiveNetworkInfo() 获取可用网络

2.
NetworkInfo[] getAllNetworkInfo 获取所有可用网络

3.
NetworkInfo getNetworkInfo(int networkType) 获取固定网络信息

4.
isNetworkTypeValid(int networkType)

Android判断当前网络状态是否连接函数

Public static Boolean isNetworkConnected(Context context) {
ConnectivityManager manager = (ConnectivityManager) context  
              .getApplicationContext().getSystemService(  
                     Context.CONNECTIVITY_SERVICE);  
        
       if (manager == null) {  
           return false;  
       }  
        
       NetworkInfo networkinfo = manager.getActiveNetworkInfo();  
        
       if (networkinfo == null || !networkinfo.isAvailable()) {  
           return false;  
       }  
   
       return true;  
    }