CODEWITHSUNDEEP
android
Peter Nelson
Peter Nelson

Reputation: 5977

Calling finish() on an Android activity doesn't actually finish

I'm calling finish() but my activity keeps on going.

I have an activity which is invoked by a menu from the main activity screen. In my activity's onCreate() method I have the following code fragment:

    // Make sure there are some events in the list.
    if (theEventArrayList.isEmpty()){
        Toast.makeText(this, "Event List is empty", Toast.LENGTH_LONG).show();
        finish();
    }
    SummarizeCurrentEvent();
    graphEvents();

If the list is empty it puts up the Toast, and I can set breakpoint on the call to finish(). If I step from that in the debugger it goes to straight to SummarizeCurrentEvent(). I thought finish() would exit the activity. Is this not the case? Where can I find out more information about this method?

Upvotes: 53

Views: 58535

Answers (6)

CodeToLife
CodeToLife

Reputation: 4171

put in manifest :

    <activity android:name=".MainActivity"
        android:noHistory="true">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

to avoid holding it in history stack of the system

Upvotes: 1

WJr
WJr

Reputation: 1

This is the case where the try...catch statement should be used.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    try {
        //...some initialization...

        // Make sure there are some events in the list.
        if (theEventArrayList.isEmpty()){
            throw new Exception("Event List is empty");
        }
        SummarizeCurrentEvent();
        graphEvents();
    } catch (Exception e) {
        Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
        finish();
    }
}

Upvotes: -1

Pedro Loureiro
Pedro Loureiro

Reputation: 11514

Adding to the other answers, you still may have (Re)onStart, onResume and onPause invoked.

I say this because in the following link, there is a table that says that for one activity to be killed, first it is invoked onPause (and probably but not guaranteed) on Stop and onDestroy.

Reference Activity

Upvotes: 4

Robby Pond
Robby Pond

Reputation: 73494

finish() just tells the activity to do what it needs to do to finish, eg. shutdown, call on onPause, report result to parent, etc. It doesn't do an exit() call or anything.

You should return after the finish() call.

Upvotes: 7

Nanne
Nanne

Reputation: 64429

You should put a return statement after that finish, because the method that called finish will be executed completely otherwise.

also, see this question: about finish() in android

Upvotes: 79

Falmarri
Falmarri

Reputation: 48615

Finish finishes the activity, but it's up to the main loop to do any UI interaction. You have to wait until the UI loop runs, which is after you return from onCreate.

Upvotes: 0

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