How to detect if app has been "minimized" by home button or hidden behind another activity

Question

I want to do a certain thing in my activity's fragment's onresume, but only if Back button has been pressed, and not if the app has been hidden behind another activity or "minimized" using "home" button/

How can I do that

score 1 · Answer 1 · edited May 23 '17 at 11:54

1

onPause() will be called when the Activity is moved to the background. onPause() is where you deal with the user leaving your activity. See the diagram here.

If another Activity comes in onPause() is called. You can override onPause(). You can do anything/save anything there. When the activity again comes into foreground onResume() is called. You can override that also, and restore anything there.

@Override
public void onPause() {
super.onPause();  // Always call the superclass method first

// Release the Camera because we don't need it when paused
// and other activities might need to use it.
if (mCamera != null) {
    mCamera.release()
    mCamera = null;
}
}
@Override
public void onResume() {
super.onResume();  // Always call the superclass method first

// Get the Camera instance as the activity achieves full user focus
if (mCamera == null) {
    initializeCamera(); // Local method to handle camera init
}
}

For Back Button see this.

edited May 23 '17 at 11:54

Community

1
1

answered Nov 17 '14 at 13:41

Mohammed Ali

2,758
5
23
41

I know that. onPause is called if the user clicks hardware or actionbar "Back" button OR if they hold Home button, or if another app's activity gets on front. I only want to do a certain thing if the user has invoked onPause by hitting the Home button and not the back buttons – Kaloyan Roussev Nov 17 '14 at 13:43
I know I can override it, but how do I detect whether its coming from the back button or the home button – Kaloyan Roussev Nov 17 '14 at 13:50
for home button see answer here: http://stackoverflow.com/questions/8881951/detect-home-button-press-in-android also see the links in that answer. This no longer works as of 4.0. – Mohammed Ali Nov 17 '14 at 13:54
http://stackoverflow.com/questions/6413700/android-proper-way-to-use-onbackpressed – Mohammed Ali Nov 17 '14 at 13:57

score 0 · Accepted Answer · answered Nov 17 '14 at 13:46

0

The onBackPressed method is available from your Activity. Passing this to your Fragment could be done through a Broadcast, or possibly an Event bus (I'd recommend Otto for this). That way, your Activity can notify your Fragment of the onBackPressed call.

answered Nov 17 '14 at 13:46

Alex Kolpa

187
1
4

can I implement an onBackPressedListener interface in the Fragment and invoke it from the activity? – Kaloyan Roussev Nov 17 '14 at 13:49
The problem is that Fragments usually have longer lifetimes than Activities. If you don't need it on your back stack, you can simply set a tag or use its container id to obtain it. Then you should be able to use a listener as you suggested. – Alex Kolpa Nov 17 '14 at 13:52
what about home button? – Mohammed Ali Nov 17 '14 at 13:56
1

As far as I know, detecting presses of the home button specifically is not possible. – Alex Kolpa Nov 17 '14 at 13:58

score 0 · Answer 3 · answered Nov 17 '14 at 13:50

0

You can do it easily: just use a variable in your sharedPreference and toggle it in onBackPressed in your activity to separate it from other actions that may cause onPause, then in onResume reset it :)

answered Nov 17 '14 at 13:50

M. Erfan Mowlaei

1,376
1
14
25

How to detect if app has been "minimized" by home button or hidden behind another activity

3 Answers3