android網路狀態判斷(wifi、3G、2G)

首先需要加入許可權

代碼如下	複製代碼
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>     <uses-permission android:name="android.permission.INTERNET"/>

檢查網路狀態碼如下

代碼如下

複製代碼

public boolean CheckNetworkState()     {         boolean flag = false;         ConnectivityManager manager = (ConnectivityManager)getSystemService(                 Context.CONNECTIVITY_SERVICE);         if(manager.getActiveNetworkInfo() != null)         {             flag = manager.getActiveNetworkInfo().isAvailable();         }         if(!flag)         {             AlertDialog.Builder builder = new AlertDialog.Builder(this);             builder.setIcon(android.R.drawable.ic_dialog_alert);             builder.setTitle(R.string.netstate);             builder.setMessage(R.string.setnetwork);             builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {                                 @Override                 public void onClick(DialogInterface dialog, int which) {                     // TODO Auto-generated method stub                     Intent mIntent = new Intent("/");                     ComponentName comp = new ComponentName("com.android.settings",                             "com.android.settings.WirelessSettings");                     mIntent.setComponent(comp);                     mIntent.setAction("android.intent.action.VIEW");                     startActivity(mIntent);                 }             });             builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {                                 @Override                 public void onClick(DialogInterface dialog, int which) {                     dialog.cancel();                 }             });             builder.create();             builder.show();         }                 return flag;             }

效果如下，使用者可以點擊確定來設定網路，比如啟動wifi

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如果希望網路連接時做一些事情的話，需要判斷當前網路狀態是否為true，為真則進行一些操作，否則設定網路。還可以用另外一種方式，其實差不多

代碼如下

複製代碼

//setnetwork     public void setNetwork()     {         AlertDialog.Builder builder = new AlertDialog.Builder(this);         builder.setIcon(android.R.drawable.ic_dialog_alert);         builder.setTitle(R.string.netstate);         builder.setMessage(R.string.setnetwork);         builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {                         @Override             public void onClick(DialogInterface dialog, int which) {                 // TODO Auto-generated method stub                 Intent mIntent = new Intent("/");                 ComponentName comp = new ComponentName("com.android.settings",                         "com.android.settings.WirelessSettings");                 mIntent.setComponent(comp);                 mIntent.setAction("android.intent.action.VIEW");                 startActivity(mIntent);             }         });         builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {                         @Override             public void onClick(DialogInterface dialog, int which) {                 dialog.cancel();             }         });         builder.create();         builder.show();     }         //NETWORK     public boolean isNetworkAvailable()     {         Context context = getApplicationContext();         ConnectivityManager connect = (ConnectivityManager)context.getSystemService(                 Context.CONNECTIVITY_SERVICE);         if(connect==null)         {             return false;         }else//get all network info         {             NetworkInfo[] info = connect.getAllNetworkInfo();             if(info!=null)             {                 for(int i=0;i<info.length;i++)                 {                     if(info[i].getState()==NetworkInfo.State.CONNECTED)                     {                         return true;                     }                 }             }         }         return false;     }

然後通過判斷如果目前狀態可用則執行相關代碼，不可用則設定網路

代碼如下	複製代碼
if(isNetworkAvailable()) { 相關代碼 }else { setNetwork(); }]

這篇文章中已經介紹了網路狀態的判斷，但是測試後發現用此方法只能夠判斷WIFI是否串連，而現在的智能機可以是wifi、3G、甚至2G。那麼如果用上面的方法就不行了需要進行一下修改，使其在網路不串連（無論wifi、3G、2G）的時候也可以判斷。代碼如下

代碼如下

複製代碼

//Check network     public void CheckNetworkState()     {         boolean flag = false;         ConnectivityManager manager = (ConnectivityManager)getSystemService(                 Context.CONNECTIVITY_SERVICE);         State mobile = manager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState();         State wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState();         //如果3G、wifi、2G等網路狀態是串連的，則退出，否則顯示提示資訊進入網路設定介面         if(mobile == State.CONNECTED||mobile==State.CONNECTING)         return;         if(wifi == State.CONNECTED||wifi==State.CONNECTING)         return;         showTips();     }         private void showTips()     {         AlertDialog.Builder builder = new AlertDialog.Builder(this);         builder.setIcon(android.R.drawable.ic_dialog_alert);         builder.setTitle(R.string.netstate);         builder.setMessage(R.string.setnetwork);         builder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {                         @Override             public void onClick(DialogInterface dialog, int which) {                 // 如果沒有網路連接，則進入網路設定介面                 startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));             }         });         builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {                         @Override             public void onClick(DialogInterface dialog, int which) {                 dialog.cancel();             }         });         builder.create();         builder.show();     }

種方式更加簡單，也更加有用，當然第一篇也有可取之處，可以加入3G狀態檢查即可
注意：別忘了加上許可權

代碼如下	複製代碼
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>