OnAppPause - onAppStop - onAppDestroy │ CloseApp - CloseScreen

Anke · August 8, 2022, 1:17pm

If the app is closed, no event is triggered. However, when the screen is closed, all events (onPause, onStop, onDestroy) are triggered.

To check this:
activityLifecycle.apk (4.7 MB)

Events in chronological order (ascending):
→ OnPause → OnStop → OnDestroy
in my tests with the APK on Android 12.

Anke · August 8, 2022, 1:29pm

Anke · August 8, 2022, 3:48pm

It seems that

“Close screen block will destroy the screen activity while the exit application just calls System.exit(0) that would terminate the app almost immediately.”
as @Kumar wrote to me via PM on AI2.

So that seems to be the reason there is not enough time to trigger the events.

May I post this @Kumar? If not, I’ll delete it again.

Kumar · August 8, 2022, 4:10pm

Yeah thats right

github.com

mit-cml/appinventor-sources/blob/dd55a7321b8d9d23bc395bd61bb7828c44c148b2/appinventor/components/src/com/google/appinventor/components/runtime/Form.java#L2449


      
          }
          
          protected void closeApplicationFromBlocks() {
            closeApplication();
          }
          
          private void closeApplicationFromMenu() {
            closeApplication();
          }
          
          private void closeApplication() {
            // In a multi-screen application, only Screen1 can successfully call System.exit(0). Here, we
            // set applicationIsBeingClosed to true. If this is not Screen1, when we call finish() below,
            // the previous form's onResume method will be called. In onResume, we check
            // applicationIsBeingClosed and call closeApplication again. The stack of forms will unwind
            // until we get back to Screen1; then we'll call System.exit(0) below.
            applicationIsBeingClosed = true;
          
            finish();
          
            if (formName.equals("Screen1")) {

Anke · August 9, 2022, 9:43am

Since my apps usually only have 1 screen open at the same time, I usually only use the closeScreen block.
Then all events are triggered.

Then there’s no reason to use the closeApplication block either.