title: Android billing - error you own this item
body: <p>I have a ndroid application with in-app billing. I want a have a subscription. i see a google sample. i introduced billing in my application. i purchase one item. but i have problem. i click a button 'purchase' start intent ... .after closing this intent(text: you own this item, i click ok) if i want click this button again app is crushed.</p>
  
  <p>logs</p>
  
  <p>i own this item.</p>
  
  <pre><code>05-31 19:02:10.416: D/Finsky(3313): [1]CarrierParamsAction.createCarrierBillingParameters: Carrier billing config is null. Device is not targeted for DCB 2.
  05-31 19:02:10.436: I/SurfaceFlinger(1705): id=170(12) createSurface 0x3d364 (1x1),1 flag=0
  05-31 19:02:10.441: E/Finsky(3313): [237] FileBasedKeyValueStore.delete: Attempt to delete 'paramspt_jJJW_8KK4rjjCyMt7_w' failed!
  05-31 19:02:10.456: D/dalvikvm(3313): GC_CONCURRENT freed 1269K, 11% free 15726K/17607K, paused 13ms+7ms
  05-31 19:02:10.471: I/ClipboardServiceEx(1865): mCBPickerDialog enter case. MSG_DISMISS_DIALOG
  05-31 19:02:10.471: D/CLIPBOARD(14751): Hide Clipboard dialog at Starting input: finished by someone else... !
  05-31 19:02:10.476: I/ClipboardServiceEx(1865): mCBPickerDialog enter case. MSG_DISMISS_DIALOG
  05-31 19:02:10.491: I/ActivityManager(1865): Displayed shortComponentName: +165ms
  05-31 19:02:10.726: I/power(1865): *** release_dvfs_lock : lockType : 1 
  05-31 19:02:10.726: D/PowerManagerService(1865): releaseDVFSLockLocked : all DVFS_MIN_LIMIT are released 
  05-31 19:02:10.726: W/ActivityManager(1865): mDVFSLock.release()
  </code></pre>
  
  <p>in a second click i have</p>
  
  <pre><code>05-31 19:08:43.331: W/System.err(15461): java.lang.IllegalStateException: Can't start async operation (launchPurchaseFlow) because another async operation(launchPurchaseFlow) is in progress.
  05-31 19:08:43.331: W/System.err(15461):    at com.market.IabHelper.flagStartAsync(IabHelper.java:725)
  05-31 19:08:43.331: W/System.err(15461):    at com.market.IabHelper.launchPurchaseFlow(IabHelper.java:289)
  05-31 19:08:43.331: W/System.err(15461):    at com.crystalreality.crystaltv.BillingActivity.performPurchaseSubscription(BillingActivity.java:65)
  05-31 19:08:43.331: W/System.err(15461):    at dalvik.system.NativeStart.run(Native Method)
  </code></pre>
  
  <p>i have a activityResult, but its code not execute</p>
  
  <pre><code>@Override
      protected void onActivityResult(int requestCode, int resultCode, Intent data) {
          Log.d(TAG, "onActivityResult(" + requestCode + "," + resultCode + "," + data);
          if(requestCode == 0) {
              finish();
          }
  
          // Pass on the activity result to the helper for handling
          if (!mHelper.handleActivityResult(requestCode, resultCode, data)) {
              // not handled, so handle it ourselves (here's where you'd
              // perform any handling of activity results not related to in-app
              // billing...
              super.onActivityResult(requestCode, resultCode, data);
          }
          else {
              Log.d(TAG, "onActivityResult handled by IABUtil.");
          }
      } 
  </code></pre>
  
  <p>purchaseFlow is code from sample.
  how i may fix it?</p>