Develop Reference

Android skipping the splash screen when re-opening the app after having pressed back

So my scenario is as such.
Let's say there is a MainActivity, which only job is to start, call installSplashScreen().setKeepOnScreenCondition { true } to show the Splash screen using the new backward compatible APIs, and then after checking some state it does startActivity(SomeActivity); finish()
Now we're on the SomeActivity and if we press the home button, the app is gone on the background. Then if we click on the launched icon, the SomeActivity is launched correctly, and the MainActivity's onCreate is never called, therefore the splash screen does not show again, and the SomeActivity shows instantly.
But if instead of pressing the home button, we press the back button, and the app is backgrounded that way, then when we click on the launcher icon, the MainActivity's oncreate is called again, and the splash screen icon flashes for a tiny fraction too making it look jarring.
My question is, does this sound like it's some wrong configuration on my part, or am I stuck with this behavior as long as I am not on a single activity architecture?

You are confused. Pressing the BACK button does not "send the app to the background". The default behaviour of the BACK button (assuming that you don't override this and provide your own behaviour) is to finish the current Activity. Normally this will take the user to the previous Activity in the current task. In your case, there is no other Activity in the task stack, so the current task is empty. This may appear to the user as "the app is sent to the background", but in reality there is nothing in the background. Your app's task is empty and so it is gone.
When the user then taps the app icon on the HOME screen or taps on the app's task in the list of recent tasks, there is no existing task to bring to the foreground, so the app is started again by creating a new task and launching the root Activity (in your case MainActivity) into the newly created task.
If you want the BACK button to just put your app into the background (instead of calling finish() on SomeActivity, which is the default behaviour) then just override onBackPressed() in SomeActivity and do this instead:
moveTaskToBack(true);

It seems like there is no solution to what I am facing as long as the Activity I want to resume to is not the Launcher activity.
From the the docs:
"Root launcher activities are activities that declare an Intent filter with both ACTION_MAIN and CATEGORY_LAUNCHER. These activities are unique because they act as entry points into your app from the app launcher and are used to start a task.
System behavior on Android 12 and higher
The system moves the activity and its task to the background instead of finishing the activity. This behavior matches the default system behavior when navigating out of an app using the Home button or gesture."
Reading the docs about the new back behavior on Android 12 and onwards tells us that pressing back when you got nothing else on the stack will act as if you pressed the home button.
There's a big exception here, and that is that when you re-open the application, if the one you just popped was not the launcher activity, it will then still need to launch that launcher activity and can't resume from where you left off in a hot state, exactly the reason why I am seeing the splash screen again.
So I think my best bet is to either ignore this for now, or fix my app to be a single-activity app, or at least keep the launcher activity be the top-level one that you exit the app from by pressing back
To indicate a couple of examples, if one wants to experience what I mean, the reproduction steps are to:
Open the app
Press the back button which will send you out of the app to the home screen
Click on the app icon again
As of today, apps like Google Photos, and Google Podcasts don't show the splash again. In contrast, apps like Google Maps, Twitter, Spotify do show the splash again for a brief second.

to call the launcher activity every time you have to clear the stack that means you have to use a flag in your manifest to tell your app not to keep activity in background try android:launchMode="singleTask" inside your activity tag in manifest the activity that you want to be killed everytime you go to background, and as far as how much time splash should be showing you can use timer for that after the timer is finished then your someActivity will be called.

Why does "Home" button call `onDestroy()` in my Android app?

On the Android dev page, it says pressing the "Home" or "Overview" button does not invoke onDestroy,
but in my app, it keeps calling onDestroy. Are there any clues?
(detail situation below)
I've built a simple app that switches from the main activity to a second activity,
but if I press the "Home" or "Overview" button on the second activity, the onDestroy gets called.
So when I go back to my app again, it shows the main activity, not the second activity.
Is this normal?
Should I save the state if I want to go back to the last activity (not the main activity) after pressing the Home or the Overview button and coming back to my app?
Android dev page that I read:
If a new activity or dialog appears in the foreground, taking focus and completely covering the activity in progress, the covered activity loses focus and enters the Stopped state. The system then, in rapid succession, calls onPause() and onStop().
and
Note: When the user taps the Overview or Home button, the system behaves as if the current activity has been completely covered.
So it is supposed to invoke only onPause and onStop, not onDestroy, isn't it?

Finally I found the culprit!
the problem was that I set android:noHistory="true" on the second activity, in the AndroidManifest.xml file.
Making this option true let the activity not leave the history,
so if another activity comes to the foreground and the user pushes the back button, the previous activity(noHistory=true) does not show up.
Similarly, if the user pushes the Home or the Overview button, then the user tries to come back to our app, the last activity(noHistory=true) does not show up either.

You have to put the Code in your Question or we can't help you.
Maybe you are calling finish() in MainActivity after you call startActivity(MainActivity.this, SecondActivity.class) ?
Use the edit-function and show us your code then we can help you more.

What exactly does moveTaskToBack() do?

From the documentation:
public boolean moveTaskToBack (boolean nonRoot)
Move the task containing this activity to the back of the activity stack. The activity's order within the task is unchanged.
What exactly does "Move the task containing this activity to the back of the activity stack" mean? I know that each task is a stack of activities, but according the the above sentence, it seems there is also a global stack of tasks as well?
When I try this method out, the current activity moves to the background, and the behaviour seems very much like when clicking the Home button (e.g. the activity is not destroyed and can be resumed later). Is there any difference between calling this function and pressing the Home button?

There is not a "global stack of tasks." There's a global stack of activities, which can be from one app or from multiple. Let's say you have an app where you can click a link, bringing you to your browser. If the browser then calls a moveTaskToBack() method, then the original app activity will open, with the previous activities on the backstack still in place.
Now imagine instead of calling the moveTaskToBack() method, the user presses the Home button. Now, pressing Back on your phone will not take you back to the original app. You'll just stay on the home screen.

Android - Is it possible to determine if an activity was started from another task?

This is pretty elaborate, so I'll try and be as clear as possible. Currently, my application needs to reload some data when it is launched. I am loading this data in the onCreate/onRestart methods of my main activity. However, I need to be careful to not reload the data if the user never leaves the current task.
For instance, if I need to start the in-built Contacts application from my main activity to select a contact, then my main activity will pause/stop while I am selecting a new contact. When I return to my main activity, onRestart will be called. In this case, because I have never left the Application's task, I do not want to reload the data. This means some check needs to be included here to determine if the user has come straight back from the Contacts app without ever leaving it.
Otherwise, if the user exits the Contacts app while it was open and re-launched the app from the launcher menu (or recent apps list, etc) - I want to close the Contacts app and reload the data when the Main activity's onRestart method is called.
Is there a way to do this without using any user-frightening permissions (e.g. GET_TASKS). I have been stuck on this problem for a long time now so any help would be GREATLY appreciated :)
Tyvm,
B. Campbell

I learned a lot from the Android docs:
Tasks and Back Stack
Navigation with Back and Up
Application Structure
Here is some highlight:
A task is a collection of activities that users interact with when
performing a certain job. The activities are arranged in a stack (the
"back stack"), in the order in which each activity is opened.
When the current activity starts another, the new activity is pushed
on the top of the stack and takes focus. The previous activity remains
in the stack, but is stopped. When an activity stops, the system
retains the current state of its user interface. When the user presses
the Back button, the current activity is popped from the top of the
stack (the activity is destroyed) and the previous activity resumes
(the previous state of its UI is restored). Activities in the stack
are never rearranged, only pushed and popped from the stack—pushed
onto the stack when started by the current activity and popped off
when the user leaves it using the Back button.
It means when your application pick up a contact, the activity stack in the task might be:
| Activity A in Contacts |
| Activity B in Your App |
| Activity C in other app|
When the user leaves a task by pressing the Home button, the current
activity is stopped and its task goes into the background. The system
retains the state of every activity in the task. If the user later
resumes the task by selecting the launcher icon that began the task,
the task comes to the foreground and resumes the activity at the top
of the stack.
Even if the user exits the Contacts app while it was open and re-launched the app from the launcher menu or recent app list, the activity stack is still like the one we see above. The only possibility that may make your acitity start from another task is another app(might be a launcher app) that start the main activity in a new task by startActivity flags, which is a rare case. In this rare case, you can simply check the uid of the app who start your activity by Binder.getCallinguid() to differentiate it.
EDIT based on comments:
You may check if activity was opened from history by FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY:
if ((getIntent().getFlags() & Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY) != 0){
}else{
}
You can also look into:
android:excludeFromRecents if you don't want your app start from recent apps
android:finishOnTaskLaunch
android:stateNotNeeded

If the data you are loading related to the application life-cycle not to a specific activity, you can load it in application class, so it will not be reloaded again unless your application task is killed.

Confuse about launchMode

I have Activity A which calls B, at which point let's say the user presses the home button:
1) If the user long presses the home button and brings out the recently launch application, it will bring the user back to activity B.
2) If the user opens my application via the shortcut ( pressing the icon of the application), it will create another instance of Activity A.
I did not set any launchMode for my activity, so I guess it's launchMode="standard", the default behaviour I want is to go back activity B.
Why is point number 2 happening? I always thought that both of the actions will lead to the same result.

Every time it should call activity B unless Dalvik machine thinks that activity B is a background process and the process space might be required for other applications,
At that point your activity may be killed and it may launch afresh when you click the icon.

It's weird...I did a total uninstall and reinstall of the app.
Without declaring launchMode, it's default to "standard", and it works just as designed.