title: Android InApp Billing : How to detect back press interrupting the purchase process?
body: <p>I'm trying to implement the inApp billing service with IabHelper. I manage to go through the full purchase process without problems. </p>
  
  <pre><code>//-----------------------------------------------
  public void billingServiceLaunchPurchase(String item) {
  //-----------------------------------------------
      if (isNetworkAvailableSync(getBaseContext())) {
          currBuyItem=item;
          billingConsummeType=1;
          mHelper.launchPurchaseFlow(BaseActivity.this, item, 10001, mPurchaseFinishedListener, "");
      }
      else {
          onBillingServiceFailed();  
      }
  }
  
      //-----------------------------------------------
      mPurchaseFinishedListener = new IabHelper.OnIabPurchaseFinishedListener() {
      //-----------------------------------------------
          public void onIabPurchaseFinished(IabResult result, Purchase purchase) 
          {
             if (result.isFailure()) {
                // Handle error
                onBillingServiceFailed();                
                return;
           }      
           else if (purchase.getSku().equals(currBuyItem)) {
               billingServiceConsumeItem();
           }
  
          }
      }; 
  
  @Override
  //-----------------------------------------------------------------------    
  protected void onActivityResult(int requestCode, int resultCode, Intent data)
  //-----------------------------------------------------------------------
  {
      if (billingServiceConnected) {
            if (!mHelper.handleActivityResult(requestCode, resultCode, data)) {     
                super.onActivityResult(requestCode, resultCode, data);
            }
            else {
                // onActivityResult handled by IABUtil.
            }
      }
      else
             super.onActivityResult(requestCode, resultCode, data);
  
  }    
  </code></pre>
  
  <p>However, I cannot detect the event when the user launches the purchase but then press the backspace on the Google confirmation screen with the button "BUY" to interrupt it.</p>
  
  <p>It neither triggers a failure on onIabPurchaseFinished nor it triggers onActivityResult so my application stays in an intermediary status.</p>
  
  <p>Please help me to solve my problem.</p>