title: Handling Airplane Mode with HTTP Requests
body: <p>My app has quite a few occasions where it makes HTTP post requests. I discovered during testing that if the user is in airplane mode when this request is made, the app crashes. So, in an effort to handle this situation elegantly, I call a function that tests whether the phone is in airplane mode immediately prior to making the <code>AsyncTask</code> call. If the function returns true, I don't make the <code>AsyncTask</code> call.</p>
  
  <p>The test itself works correctly. The user is notified that they must turn off airplane mode and them come back and try again. The problem is that after airplane mode is turned off, and the <code>AsyncTask</code> proceeds, my HTTP post crashes the app. If airplane mode was never on in the first place, everything runs smoothly.</p>
  
  <p>I can't figure out what to do. Is there a better way to test for airplane mode in the first place? Or is there something else that I need to do after blocking the <code>AsyncTask</code> to restore the system state such that the http request will succeed.</p>
  
  <p>Any advice is appreciated. Here is some code to hopefully make this more clear. If there is additional code that will help, please let me know. Thanks!</p>
  
  <pre><code>public class LoginActivity extends Activity {
          @Override
          protected void onCreate(Bundle savedInstanceState) {
                  super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_login);
  
              context = this;
  
              btnLogin.setOnClickListener(new View.OnClickListener() {
                  public void onClick(View view) {
                  UserFunctions userFunction = new UserFunctions(context);
                  if (userFunction.isAirplaneModeOn(context)) {
                      userFunction.warnAboutAirplaneMode(context);
                      return;
                  }
  
                  new Login().execute();  
  
              });
      }
  
      class Login extends AsyncTask&lt;String, String, String&gt; {
  
          private JSONParser jsonParser = new JSONParser();
          private JSONObject json;
  
          @Override
          protected String doInBackground(String... args) {
  
              String URL = context.getResources().getString(R.string.dbURL) + context.getResources().getString(R.string.attemptLogin_php);
  
                      //this next line is the one that crashes - iff the user was
                      // previously in airplane mode. If there weren't ever in airplane
                      // mode, this runs just fine
              json = jsonParser.makeHttpRequest(URL, params);
  
                      ...
  
      }
  }
  </code></pre>
  
  <p>Here is the UserFunctions class:</p>
  
  <pre><code>    public class UserFunctions {
  
              @SuppressLint( "NewApi" )
              @SuppressWarnings("deprecation")
              public boolean isAirplaneModeOn(Context context) {
  
                  if(Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.JELLY_BEAN_MR1){
                      return Settings.Global.getInt(context.getContentResolver(),
                         Settings.Global.AIRPLANE_MODE_ON, 0) != 0;
                  } else {
                      return Settings.System.getInt(context.getContentResolver(),
                             Settings.System.AIRPLANE_MODE_ON, 0) != 0;
                  }
  
              }
  
              public void warnAboutAirplaneMode(Context context) {
  
                  AlertDialog.Builder builder = new AlertDialog.Builder(context)
                      .setTitle("Airplane Mode Is On")
                      .setIcon(R.raw.airplane_mode)
                      .setCancelable(false)
                      .setMessage("Your phone is in airplane mode. Please turn this off then try again.")
  
                      .setNeutralButton("OK", new DialogInterface.OnClickListener() {
                          public void onClick(DialogInterface dialog, int id) {
                              dialog.cancel();
                          }
  
                      });
  
                  AlertDialog alert = builder.create();
                  alert.show();   
              }
  
          }
  </code></pre>