Android main activity destroy(finish) automatically

Question

In my App there is three activities: A, B, and C. Activity A is the main activity.

When I start Activity B from A using Intent, A is automatically destroyed. However, I am not finished with A when I start B. Then, when I press the back button in the device the A is started using onCreate and I've lost all my data since I am not using an Intent to go back.

The same happens when opening C from B.

button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                startActivity(new Intent(ActivityA.this,
                        ActivityB.class));
            }
        });

What's going on? How do I fix this?

Answer 1

This was a mistake by me due to this the Activities were automatically destroying. I Checked the option under Setting=>Developer Option=>Don't Keep Activities. Due to that destroyed every activity as soon as the user leave it.

By Unchecked this option my app working fine.

Answer 2

If you are using 'Activity B' to get some sort of one-off result then it sounds like you need to be using the startActivityForResult construct. See [the docs](http://developer.android.com/reference/android/app/Activity.html#startActivityForResult(android.content.Intent, int))

However, to maintain state information about 'Activity A' without persisting it anywhere you want to be bundling all the information (fields the user has filled in etc.) into the Intent bundle passed to 'Activity B'. This bundle is delivered to 'Activity B's onCreate (and a few other lifecycle points) where you can continue populating any pertinent information from 'Activity B' and writing that information back to the intent bundle before restarting 'Activity A' with the modd'ed bundle when you are done with 'Activity B'. But here be dragons. This specific mechanism is employed in our app with a strict (wrong?) control over the back-stack. Specifically our 'Activity A' has the special manifest declaration of android:noHistory="true". This means that we also control what happens when the back button is pressed by overriding onBackPressed() at each activity and sending that same bundle through to a new instance of the activity we just came from. It looks like a normal back stack but since we are wanting to remember user input without persisting that information anywhere then it's a usable solution.

This allows for a wizard like input with each stage of the wizard input being it's own activity and only validated and correct information being persisted at the end.

An alternative would be to temporarily stored 'Activity A's data in the SharedPreferences area so that on restarting Activity A you can pull out the appropriate bits reassembling the original state of 'Actvity A' when you left it. Rest assured there is very little you can do when Android wants to kill your Activity A but you can accommodate it's very reasonable killing with the approaches outlined here.

Answer 3

Maybe it is not you that is destroying your activity.

From the page about Activity Life cycle: (Emphasis mine)

If an activity is paused or stopped, the system can drop the activity from memory by either asking it to finish, or simply killing its process. When it is displayed again to the user, it must be completely restarted and restored to its previous state.

There explicit says that the system can kill your activity process.

Some possibilities is your device is low on memory, or your activities is memory hungry, making the system kill it.

Edit

In order to maintain your data, between the activities even if it gets destroyed. One way is to use the Application class, check this answer on Using the Android Application class to persist data, maybe that's what you're looking for.