title: zxing onActivityResults not firing
body: <p>I'm trying to pull data from a QR code via zxing using the following code (basically copypasted from a tutorial, with names changed to protect the innocent):</p>
  
  <pre><code>            //Check for Barcode scanner, if not found put up an alert that allows user to install it.
              PackageManager pm = getPackageManager();
              try {
                  ApplicationInfo appInfo = pm.getApplicationInfo("com.google.zxing.client.android", 0);
                  Intent intent = new Intent(
                  "com.google.zxing.client.android.SCAN");
                  intent.putExtra("SCAN_MODE", "QR_CODE_MODE");//for Qr code, its "QR_CODE_MODE" instead of "PRODUCT_MODE"
                  intent.putExtra("SAVE_HISTORY", false);//this stops saving ur barcode in barcode scanner app's history
                  startActivityForResult(intent, 0);
              } catch (NameNotFoundException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
                   new AlertDialog.Builder(BitcoinAddressUtilityActivity.this)
                      .setTitle("WARNING:")
                      .setMessage("You don't have Barcode Scanner installed. Please install it.")
                       .setCancelable(false)
                      .setNeutralButton("Install it now", new DialogInterface.OnClickListener() {
                      public void onClick(DialogInterface dialog, int whichButton) {         
                                    Uri uri = Uri.parse("market://search?q=pname:com.google.zxing.client.android");
                                    startActivity(new Intent(Intent.ACTION_VIEW, uri));
                              }
                      })
                      .show();
  
              }
  
  
          }
  
          public void onActivityResult(int requestCode, int resultCode, Intent intent) {
                 if (requestCode == 0) {
                    if (resultCode == RESULT_OK) {
                       String contents = intent.getStringExtra("SCAN_RESULT");
                       String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
                       // Handle successful scan
                       EditText passphrase = (EditText) findViewById(R.id.txtPassphrase);
                       passphrase.setText(contents);
                    } else if (resultCode == RESULT_CANCELED) {
                       // Handle cancel
                    }
                 }
              }
  
  
      });
  </code></pre>
  
  <p>It executes just fine without errors, but onActivityResults never fires, I even get a warning:</p>
  
  <p><code>The method onActivityResult(int, int, Intent) from the type new View.OnClickListener(){} is never used locally</code></p>
  
  <p>I'll fully admit that I'm an activity/intent noob, so if someone wants to answer in the form of a tutorial I'll gladly accept that - I don't just want a code fix, I want to know why it's not working in the first place.</p>