Android - Avoiding an activity to destroy, just stopping or pausing it when pushing the back button

Question

I would like to pausing or putting the application on background when pressing the back button, I don't want the application to go through the destroy state. Things are when I override onKeyDown and when I force to pause or stop the application by using onPause, I have some issuees with the wakelock and application crash, but when I press home button I go through onPause method and I have no exception, it's weird!!

Just write your activity to properly save its state, using `onSaveInstanceState()`. No activity can live forever, as Android destroys even paused activities to reclaim RAM. — CommonsWare, Mar 19 '10 at 13:18
I am working on GPS application embedded on a car device. When an accident appears, my service resume the application to display the accident event. If the user click on the back button, application is destroyed and when the service resume it, it take some time to recreate activities and then the accident event shows up. If the system needs to destroy the application, I am sure the user won't be annoyed by the recreation otherwise the application mustn't be destroyed, it's a security matter! — Ghostwan, Mar 19 '10 at 13:58
"I am working on GPS application embedded on a car device." Then you have control over the firmware and can do things beyond the SDK (and, frankly, beyond StackOverflow's general ability to help). "If the user click on the back button, application is destroyed and when the service resume it, it take some time to recreate activities and then the accident event shows up." Work on speeding up performance of opening the activities, then. "the application mustn't be destroyed, it's a security matter!" Android is probably the wrong choice of OS for your application. — CommonsWare, Mar 19 '10 at 14:03
Loool "Android is probably the wrong choice of OS for your application" my client doesn't think so! — Ghostwan, Mar 19 '10 at 15:29
I'am just asking how to put your activity on pause state like android did it when you click the home button. — Ghostwan, Mar 19 '10 at 15:31

score 19 · Answer 1 · edited May 22 '17 at 09:34

19

Try to use the method onBackPressed(), like this:

@Override
public void onBackPressed() {
    moveTaskToBack(true);
}

edited May 22 '17 at 09:34

answered May 03 '11 at 11:07

Cristiano Santos

2,157
2
35
53

3

onBackPressed() is valid since API Level 5, so if you're not supporting earlier devices, this answer is better. – Evi Song May 09 '13 at 15:43

score 11 · Accepted Answer · edited Mar 08 '13 at 19:38

11

The answer is

public boolean onKeyDown(int keyCode, KeyEvent event)
{

    if (keyCode == KeyEvent.KEYCODE_BACK)
    {
        moveTaskToBack(true);
        return true; // return
    }

    return false;
}

edited Mar 08 '13 at 19:38

Peter Ajtai

56,972
13
121
140

answered Mar 19 '10 at 16:22

Ghostwan

263
1
4
11

Other case, how to do it when user click backend Activity, It not seem that don't call onKeyDown. – kangear Jan 25 '15 at 04:42
okay, I fond the solution for touch outside the Windows.http://stackoverflow.com/a/5831214/2193455 – kangear Jan 25 '15 at 04:58

score 0 · Answer 3 · answered Nov 19 '16 at 12:43

0

@Override
public void onBackPressed() {
    if(mWebView.canGoBack())
        mWebView.goBack();
    else
        //super.onBackPressed();
        moveTaskToBack(true);

}

answered Nov 19 '16 at 12:43

Denny Weinberg

2,492
1
21
34

Android - Avoiding an activity to destroy, just stopping or pausing it when pushing the back button

3 Answers3

Linked