Android网络编程ConnectivityManager和NetworkInfo详解

清疚 2022-06-17 01:00 804阅读 0赞

一.   ConnectivityManager详解

**概要**

ConnectivityManager是网络连接相关的管理器，它主要用于查询网络状态并在网络发生改变时发出状态变化通知。这个类主要负责的下列四个方面：

1.  监控网络状态（包括WiFi, GPRS, UMTS等）。

2.  当网络连接改变时发送广播Intent。

3.  当一种网络断开时，试图连接到另一种网络进行故障处理。

4.  提供一系列接口让应用程序查询可获得的网络的粗粒度和细粒度状态。

**  比较重要的几个类常量**

**比较重要的方法**

**二. NetworkInfo详解**

NetworkInfo是一个描述网络状态的接口，可通过ConnectivityManager调用getActiveNetworkInfo()获得当前连接的网络类型。

NetworkInfo有两个枚举类型的成员变量NetworkInfo.DetailedState和NetworkInfo.State，用于查看当前网络的状态。其中NetworkInfo.State的值包括：

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   <td style="word-break:break-all; border:1px solid rgb(153,153,153); padding:5px 10px; min-height:25px; min-width:25px; height:25px; background-color:inherit"> CONNECTED&nbsp;</td> 
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      已连接 
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   <td style="word-break:break-all; border:1px solid rgb(153,153,153); padding:5px 10px; min-height:25px; min-width:25px; height:25px; background-color:inherit"> CONNECTING&nbsp;</td> 
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      正在连接 
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   <td style="word-break:break-all; border:1px solid rgb(153,153,153); padding:5px 10px; min-height:25px; min-width:25px; height:25px; background-color:inherit"> DISCONNECTED&nbsp;</td> 
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     <br> 
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   <td style="word-break:break-all; border:1px solid rgb(153,153,153); padding:5px 10px; min-height:25px; min-width:25px; height:25px; background-color:inherit"> DISCONNECTING&nbsp;</td> 
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     <br style="background-color:inherit"> 
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   <td style="word-break:break-all; border:1px solid rgb(153,153,153); padding:5px 10px; min-height:25px; min-width:25px; height:25px; background-color:inherit"> SUSPENDED&nbsp;</td> 
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   <td style="word-break:break-all; border:1px solid rgb(153,153,153); padding:5px 10px; min-height:25px; min-width:25px; height:25px; background-color:inherit"> UNKNOWN&nbsp;</td> 
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     <br> 
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NetworkInfo.DetailedState则状态描述更为详细。

NetworkInfo还包括一系列可用的方法用于判断当前网络是否可用，如下：

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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">NetworkInfo.DetailedState</a> 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getDetailedState</a>() 
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      Reports the current fine-grained state of the network. 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getExtraInfo</a>() 
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      Report the extra information about the network state, if any was provided by the lower networking layers., if one is available. 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">String</a> 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getReason</a>() &nbsp;如果数据网络连接可用，但是连接失败，则通过此方法可获得尝试链接失败的原因 
    </div> 
    <div style="min-width:2px; background-color:inherit">
      Report the reason an attempt to establish connectivity failed, if one is available. 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">NetworkInfo.State</a> 
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    <div style="min-width:2px; background-color:inherit"> 
     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getState</a>() &nbsp; 
     <span style="color:rgb(255,0,0)">获取网络连接的粗粒度状态</span> 
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    <div style="min-width:2px; background-color:inherit">
      Reports the current coarse-grained state of the network. 
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      int 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getSubtype</a>() &nbsp; 
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    <div style="min-width:2px; background-color:inherit">
      Return a network-type-specific integer describing the subtype of the network. 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">String</a> 
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    <div style="min-width:2px; background-color:inherit"> 
     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getSubtypeName</a>() 
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      Return a human-readable name describing the subtype of the network. 
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      int 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getType</a>()报告当前网络从属的网络类型 
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    <div style="min-width:2px; background-color:inherit">
      Reports the type of network to which the info in this&nbsp; 
     <code style="font-size:13px; line-height:16px; color:rgb(0,102,0); background-color:inherit">NetworkInfo</code>&nbsp;pertains. 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">getTypeName</a>() 
     <span style="color:rgb(34,34,34); line-height:1.5">报告当前网络从属的网络类型，更明确的方式如wifi,和mobile等。</span> 
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    <div style="min-width:2px; background-color:inherit">
      Return a human-readable name describe the type of the network, for example "WIFI" or "MOBILE". 
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      boolean 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">isAvailable</a>() &nbsp; 
     <span style="color:rgb(255,0,0)">判断当前网络是否可用</span> 
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    <div style="min-width:2px; background-color:inherit">
      Indicates whether network connectivity is possible. 
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      boolean 
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    <div style="min-width:2px; background-color:inherit"> 
     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">isConnected</a>() &nbsp; 
     <span style="color:rgb(255,0,0)">判断当前网络是否存在，并可用于数据传输</span> 
    </div> 
    <div style="min-width:2px; background-color:inherit">
      Indicates whether network connectivity exists and it is possible to establish connections and pass data. 
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      boolean 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">isConnectedOrConnecting</a>() &nbsp; 
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      Indicates whether network connectivity exists or is in the process of being established. 
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      boolean 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">isFailover</a>() 
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    <div style="min-width:2px; background-color:inherit">
      Indicates whether the current attempt to connect to the network resulted from the ConnectivityManager trying to fail over to this network following a disconnect from another network. 
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      boolean 
    </div> </td> 
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     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">isRoaming</a>() &nbsp; 
     <span style="color:rgb(255,0,0)">判断设备当前是否在网络上漫游</span> 
    </div> 
    <div style="min-width:2px; background-color:inherit">
      Indicates whether the device is currently roaming on this network. 
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    <div style="min-width:2px; background-color:inherit"> 
     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">String</a> 
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    <div style="min-width:2px; background-color:inherit"> 
     <a style="color:rgb(37,138,175); text-decoration:none; background-color:inherit" rel="nofollow">toString</a>( 
     <span style="color:rgb(255,0,0)">) &nbsp;返回一个包含该网络的简单的易懂的字符串描述。</span> 
    </div> 
    <div style="min-width:2px; background-color:inherit">
      Returns a string containing a concise, human-readable description of this object. 
    </div> 
    <div> 
     <br> 
    </div> </td> 
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**一般来说很少需要用到所有的内容。最后奉上一点点干货：**

public class NetWorkUtil { private static String LOG_TAG = "<span style="font-family: Arial, Helvetica, sans-serif;">NetWorkUtil</span><span style="font-family: Arial, Helvetica, sans-serif;">";</span> public static boolean isNetworkAvailable(Context context) { ConnectivityManager connectivity = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); if (connectivity == null) { Log.w(LOG_TAG, "无法获得ConnectivityManager"); } else { NetworkInfo[] info = connectivity.getAllNetworkInfo(); if (info != null) { for (int i = 0; i < info.length; i++) { if (info[i].isAvailable()) { return true; } } } } return false; } public static boolean checkNetState(Context context){ boolean netstate = false; ConnectivityManager connectivity = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE); if(connectivity != null) { NetworkInfo[] info = connectivity.getAllNetworkInfo(); if (info != null) { for (int i = 0; i < info.length; i++) { if (info[i].getState() == NetworkInfo.State.CONNECTED) { netstate = true; break; } } } } return netstate; } public static boolean isNetworkRoaming(Context context) { ConnectivityManager connectivity = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); if (connectivity == null) { Log.w(LOG_TAG, "couldn't get connectivity manager"); } else { NetworkInfo info = connectivity.getActiveNetworkInfo(); if (info != null && info.getType() == ConnectivityManager.TYPE_MOBILE) { TelephonyManager tm = (TelephonyManager) context .getSystemService(Context.TELEPHONY_SERVICE); if (tm != null && tm.isNetworkRoaming()) { return true; } else { } } else { } } return false; } public static boolean isMobileDataEnable(Context context) throws Exception { ConnectivityManager connectivityManager = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); boolean isMobileDataEnable = false; isMobileDataEnable = connectivityManager.getNetworkInfo( ConnectivityManager.TYPE_MOBILE).isConnectedOrConnecting(); return isMobileDataEnable; } public static boolean isWifiDataEnable(Context context) throws Exception { ConnectivityManager connectivityManager = (ConnectivityManager) context .getSystemService(Context.CONNECTIVITY_SERVICE); boolean isWifiDataEnable = false; isWifiDataEnable = connectivityManager.getNetworkInfo( ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting(); return isWifiDataEnable; } }