如何在沒有連接的情況下彈出默認的連接失敗對話框？

Question

每當應用程序需要互聯網連接和連接失敗，我得到一個消息對話框

Connection failed
This application requires network access. Enable mobile network or Wi-Fi to download data.

和兩個按鈕，設置，取消。

如何檢測沒有互聯網連接？
如何在我的應用程序中彈出相同的對話框？

Answer 1

在這裏你可以找到關於如何建立對話

http://developer.android.com/guide/topics/ui/dialogs.html

這裏引用的代碼片段，應該幫助您檢測網絡連接：

http://www.androidsnippets.org/snippets/131/

BTW：WASN」你是否已經在2009年11月15日提出這個問題？ http://groups.google.com/group/android-beginners/browse_thread/thread/715cedfc5fd6f020?utoken=QyP-dzQAAACEe9Lph6eUOAakqA3-BnR-KvPfK0ltyCETgVsCM3D7GeEWTAM9S5G8WBs1q2tBppm1FwwMIvCGKnxkm-CrwSdp

Answer 2

/** 
* Checks if we have a valid Internet Connection on the device. 
* @param ctx 
* @return True if device has internet 
* 
* Code from: http://www.androidsnippets.org/snippets/131/ 
*/ 
public static boolean haveInternet(Context ctx) { 

    NetworkInfo info = (NetworkInfo) ((ConnectivityManager) ctx 
      .getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo(); 

    if (info == null || !info.isConnected()) { 
     return false; 
    } 
    if (info.isRoaming()) { 
     // here is the roaming option you can change it if you want to 
     // disable internet while roaming, just return false 
     return true; 
    } 
    return true; 
} 
/** 
    * Display a dialog that user has no internet connection 
    * @param ctx1 
    * 
    * Code from: http://osdir.com/ml/Android-Developers/2009-11/msg05044.html 
    */ 
    public static void showNoConnectionDialog(Context ctx1) { 
     final Context ctx = ctx1; 
     AlertDialog.Builder builder = new AlertDialog.Builder(ctx); 
     builder.setCancelable(true); 
     builder.setMessage(R.string.no_connection); 
     builder.setTitle(R.string.no_connection_title); 
     builder.setPositiveButton(R.string.settings, new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog, int which) { 
       ctx.startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS)); 
      } 
     }); 
     builder.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() { 
      public void onClick(DialogInterface dialog, int which) { 
       return; 
      } 
     }); 
     builder.setOnCancelListener(new DialogInterface.OnCancelListener() { 
      public void onCancel(DialogInterface dialog) { 
       return; 
      } 
     }); 

     builder.show(); 
    }