Android 网络切换 发送多次广播问题

浏览数：26 / 时间：2015年06月11日

     

       最近发现做项目监听网络切换广播，根据网络条件切换一些设置.测试发现每次3G-WIFI 或者WIFI到3G，网络切换的广播都会发出多次.比如3G-->WIFI 

       会发送三个广播 1.连接wifi  2.关闭手机网络 3.连接wifi  有没有方法判断这个过程呢？那就来看一个类 

       http://www.androidcommunitydocs.com/reference/android/net/ConnectivityManager.html   （官方API 文档）

      public class

        ConnectivityManager  extends Object

            java.lang.Object
                ? android.net.ConnectivityManager

        Class that answers queries about the state of network connectivity. It also notifies applications when network connectivity changes. Get an instance of this class by calling                              Context.getSystemService(Context.CONNECTIVITY_SERVICE).

     

   The primary responsibilities of this class are to 该类主要职责:

  1. Monitor network connections (Wi-Fi, GPRS, UMTS, etc.)  监视网络连接
  2. Send broadcast intents when network connectivity changes  网络连接变化时发送广播
  3. Attempt to "fail over" to another network when connectivity to a network is lost  当当前网络不可用时尝试切换到其他网络
  4. Provide an API that allows applications to query the coarse-grained or fine-grained state of the available networks 提供API给应用查询粗略或精细的网络状态

      (http://developer.android.com/training/monitoring-device-state/connectivity-monitoring.html)

     有了这些接着我们打印一下，在接受到网络变化的广播时.传过来的网络状态与当前激活的网络状态有什么不同 代码如下 ： 

        

       

 1 @Override
 2     public void onReceive(Context context, Intent intent) {
 3          String action = intent.getAction();
 4          Log.i("MyReceiver",  action);
 5         if(ConnectivityManager.CONNECTIVITY_ACTION.equals(action)){
 6             Bundle b = intent.getExtras();
 7             if(b == null){
 8                 Log.i("MyReceiver",  "b == null ");
 9                 return ;
10             }
11             NetworkInfo netInfo = (NetworkInfo) b.get(ConnectivityManager.EXTRA_NETWORK_INFO);
12             NetworkInfo.State state = netInfo.getState();
13             int netInfoType = netInfo.getType();
14             
15             ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
16             if(cm == null){
17                  Log.i("MyReceiver", "ConnectivityManager == null");
18                 return ;
19             }
20             NetworkInfo activeNetInfo = cm.getActiveNetworkInfo();
21             if(state != null){
22                  Log.i("MyReceiver",  state.name());
23                  Log.i("MyReceiver",  "state : " + netInfo.getTypeName() + " : " + netInfo.getType());
24             }else{
25                  Log.i("MyReceiver", "state == null");
26             }
27             
28             
29             if(activeNetInfo != null){
30                 int activeNetType = activeNetInfo.getType();
31                 Log.i("MyReceiver",  activeNetInfo.getTypeName() + " : " + activeNetInfo.getType());
32             }else{          
                   Log.i("MyReceiver", "activeNetInfo == null ");
43             }
45             
46         }
47 
48     }

   使用手机进行网络间切换，打印如下 ： 

   

wifi ---> 3G
03-17 17:56:45.526: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 17:56:45.526: I/MyReceiver(13406): DISCONNECTED
03-17 17:56:45.526: I/MyReceiver(13406): state : mobile : 0
03-17 17:56:45.531: I/MyReceiver(13406): activeNetInfo == null

03-17 17:56:45.991: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 17:56:45.991: I/MyReceiver(13406): CONNECTED
03-17 17:56:45.991: I/MyReceiver(13406): state : WIFI : 1
03-17 17:56:45.991: I/MyReceiver(13406): activeNetInfo == null

03-17 17:56:49.491: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 17:56:49.496: I/MyReceiver(13406): DISCONNECTED
03-17 17:56:49.496: I/MyReceiver(13406): state : WIFI : 1
03-17 17:56:49.496: I/MyReceiver(13406): mobile : 0

03-17 17:56:49.966: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 17:56:49.966: I/MyReceiver(13406): CONNECTED
03-17 17:56:49.966: I/MyReceiver(13406): state : mobile : 0
03-17 17:56:49.966: I/MyReceiver(13406): mobile : 0

3G-->wifi

03-17 18:00:35.286: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:00:35.286: I/MyReceiver(13406): CONNECTED
03-17 18:00:35.286: I/MyReceiver(13406): state : WIFI : 1
03-17 18:00:35.291: I/MyReceiver(13406): WIFI : 1

03-17 18:00:40.641: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:00:40.641: I/MyReceiver(13406): DISCONNECTED
03-17 18:00:40.641: I/MyReceiver(13406): state : mobile : 0
03-17 18:00:40.641: I/MyReceiver(13406): WIFI : 1

03-17 18:00:41.506: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:00:41.506: I/MyReceiver(13406): CONNECTED
03-17 18:00:41.506: I/MyReceiver(13406): state : WIFI : 1
03-17 18:00:41.506: I/MyReceiver(13406): WIFI : 1


wifi --3G --WIFI
03-17 18:02:54.861: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:02:54.861: I/MyReceiver(13406): DISCONNECTED
03-17 18:02:54.861: I/MyReceiver(13406): state : WIFI : 1
03-17 18:02:54.861: I/MyReceiver(13406): WIFI : 1

03-17 18:02:55.331: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:02:55.331: I/MyReceiver(13406): CONNECTED
03-17 18:02:55.331: I/MyReceiver(13406): state : mobile : 0
03-17 18:02:55.331: I/MyReceiver(13406): WIFI : 1

03-17 18:02:56.771: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:02:56.771: I/MyReceiver(13406): CONNECTED
03-17 18:02:56.771: I/MyReceiver(13406): state : WIFI : 1
03-17 18:02:56.771: I/MyReceiver(13406): WIFI : 1

03-17 18:02:57.171: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:02:57.171: I/MyReceiver(13406): DISCONNECTED
03-17 18:02:57.171: I/MyReceiver(13406): state : mobile : 0
03-17 18:02:57.171: I/MyReceiver(13406): WIFI : 1

03-17 18:02:57.771: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:02:57.771: I/MyReceiver(13406): CONNECTED
03-17 18:02:57.771: I/MyReceiver(13406): state : WIFI : 1
03-17 18:02:57.771: I/MyReceiver(13406): WIFI : 1


关闭wifi
03-17 18:08:06.381: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:08:06.381: I/MyReceiver(13406): DISCONNECTED
03-17 18:08:06.381: I/MyReceiver(13406): state : WIFI : 1
03-17 18:08:06.386: I/MyReceiver(13406): activeNetInfo == null

关闭3G

03-17 18:09:23.366: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:09:23.366: I/MyReceiver(13406): DISCONNECTED
03-17 18:09:23.371: I/MyReceiver(13406): state : mobile : 0
03-17 18:09:23.371: I/MyReceiver(13406): activeNetInfo == null


打开wifi

03-17 18:09:52.096: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:09:52.096: I/MyReceiver(13406): CONNECTED
03-17 18:09:52.096: I/MyReceiver(13406): state : WIFI : 1
03-17 18:09:52.096: I/MyReceiver(13406): WIFI : 1

打开3G

03-17 18:10:42.976: I/MyReceiver(13406): android.net.conn.CONNECTIVITY_CHANGE
03-17 18:10:42.976: I/MyReceiver(13406): CONNECTED
03-17 18:10:42.976: I/MyReceiver(13406): state : mobile : 0
03-17 18:10:42.976: I/MyReceiver(13406): mobile : 0

根据这些状态，在网络切换的时候 我们可以总结出一些规律 ：

 1.网络在切换之前处于断开状态时 activeNetInfo == null 

 2.当网络状态不同时一般处于中间状态

 3.网络切换有可能发送重复的广播 （是这样吗？求高手解答）

 加入一些判断然后测试代码如下 ：

@Override
    public void onReceive(Context context, Intent intent) {
         String action = intent.getAction();
         Log.i("MyReceiver",  action);
        if(ConnectivityManager.CONNECTIVITY_ACTION.equals(action)){
            Bundle b = intent.getExtras();
            if(b == null){
                Log.i("MyReceiver",  "b == null ");
                return ;
            }
            NetworkInfo netInfo = (NetworkInfo) b.get(ConnectivityManager.EXTRA_NETWORK_INFO);
            NetworkInfo.State state = netInfo.getState();
            int netInfoType = netInfo.getType();
            if(MyApplication.cacheState == null){
                MyApplication.cacheState = state ;
                MyApplication.netType = netInfoType; // 移动网络 (2G/3G/4G 间切换)  or  wifi 
            }else if(MyApplication.cacheState == state && MyApplication.netType == netInfo.getType()){
                 Log.i("MyReceiver",  "state : " + state.name() +" -- " + netInfo.getTypeName() + " : " + netInfo.getType());
                 Log.i("MyReceiver",  " 相同 状态广播  ");
                return ;
            }
            ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            if(cm == null){
                 Log.i("MyReceiver", "ConnectivityManager == null");
                return ;
            }
            NetworkInfo activeNetInfo = cm.getActiveNetworkInfo();
            if(activeNetInfo != null){
                int activeNetType = activeNetInfo.getType();
                Log.i("MyReceiver",  activeNetInfo.getTypeName() + " : " + activeNetInfo.getType());
                if(activeNetType != netInfoType){  // 类型不同  认为是中间状态 不处理 
                    Log.i("MyReceiver", "类型不同 判断处于中间状态  ：  不处理 " );
                }else{
                     MyApplication.cacheState = state ;
                     MyApplication.netType = netInfoType;
                     Log.i("MyReceiver",  "当前操作   state : " + state.name() +" -- " + netInfo.getTypeName() + " : " + netInfo.getType());
                }
            }else{
                MyApplication.cacheState = state ;
                MyApplication.netType = netInfoType;
                Log.i("MyReceiver", "activeNetInfo == null ");
                 Log.i("MyReceiver",  "当前操作   state : " + state.name() +" -- " + netInfo.getTypeName() + " : " + netInfo.getType());
            }
            
        }

    }

}

 

  测试了一下，已经满足了我的要求.只是看起来方法有点笨. 应该会有更加简洁准确的方法，希望有知道的朋友提供一下思路。

 

      

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