Develop Reference

Adding use to the home button

When you press the home button, what does it do by default?
I want to keep what it does by default, but make sure it ends my music as well.
For example:
public void onBackPressed() {
return;
I disabled my back button.
I want to make it so the home button does what it does, but i want to call my
this.stopService(new Intent(this, Music.class));
in the method too.

It is not possible to override "Home" key press just like you did for Back button press. In fact you're not supposed to over ride home key press because user presses Home key to quickly come to the launcher.
Even if you try to override onKeyDown(), you'll see that Home key press will not invoke this function.
But pressing Home key will surely call onStop() of your activity and hence you can stop your music service in onStop(). Hope this helps.

When you press the home button, what does it do by default?
It brings the home screen activity to the foreground.
I want to keep what it does by default, but make sure it ends my music as well.
Stop the music in onPause() or onStop() of your foreground activity, as these will be called when it loses the foreground to the home screen activity.

If you are talking in coding sense -
The home button brings the default launcher to the foreground.
Call onPause() or onStop with super.onPause() or super.onStop() inside of the method.
If you are talking in literal terms with nothing to do with code then..
The home button launches the default launcher activity, this can be cleared if you installed the launcher on some devices by going settings > applications > manage find the application and then go clear defaults
When the music stops is decided by the developers code, you cant change how it works sorry.

User leaves activity by going back

Im connected to a chat server which gives me messages i print out in a textview. This continues when the user leaves the application by pressing the home key etc etc. I would like to close all streams if the user goes back with the phones back button to the previous activity. Problem is that onStop() and onPause() are both called independent of if the Home key was pressed or the back key. Its just called when the activity loses focus or visibility, doesnt matter which way it happened.
How do i find out if the back key was pressed, and not home?

You can implement your own version of onBackPressed(). That way you'll know every time it's pressed and can do what ever you need to in that callback. So do something like this:
public void onBackPressed(){
//Do the stuff you want to do
//Then call the parent class version function to allow it to do any other stuff
// that needs to happen as well.
super.onBackPressed();
}

Difference between android Home key and Back key and their behaviour

Can anyone point me out or explain what is the difference between android Home key and Back key and their respective behavior related to an android app/activity.
Thank you.

Back Key :
If you press Back Key, onPause(), onStop() and onDestroy() callbacks will called.
Activity will created again by system calls onCreate() callback, then onStart() and onResume() callbacks will be followed.
Home Key :
If you press Home Key, onPause() and onStop() callbacks will called.
Here Activity will restart by system calls onRestart() callback, then onStart() and onResume() callbacks will be followed.

In addition to #Fosco's comments, using back will usually cause an app to exit, where home will leave it running. This is dependent on the application, but the general pattern is to exit the app when using back on the last activity.

Back key destroys the current Activity, home key doesn't. In the Activity lyfecycle, pressing back calls all the way to current activity's onDestroy() method. On the other hand, pressing home pauses the Activity, which stays alive in background.

The home key takes you to the home screen, the back key takes you back to the previous activity (or home if there's no activity to go back to.)
If you are at the home screen and launch Messaging, then hit back, it's the same as hitting the home key.
If you're in Email and get an alert for a text message, and you choose the notification which takes you to Messaging, then hit Back, you'll go back to Email.
edit: as mentioned by Tim Coker, when the back button takes you to the home screen, it usually terminates the activity. I think this is based on the app, whether it terminates or stays resident.

Different state storage behavior for "Back" vs "Home"

I am still learning the ins and outs of Android development. I am playing around with the Notepad tutorial application to try and get different behavior.
Right now, I want to have the application do the following in the NoteEdit activity:
1) If the Back button is pressed, current state is ignored; basically, it's like an implicit cancel, and you are taken back to the list.
2) If the Home button is pressed, it takes you to the home page as normal. However, if you open the application again, it should go back into the NoteEdit activity in the same state as when you left (IE, if you were partway through an edit, for example).
I removed the "saveState" stuff from onPause, because I don't want to store to the DB unless "Confirm" is pressed (instead, I moved the call to saveState to the confirm button). By doing this, hitting "Back" basically throws out your changes, which is what I want. However, going Home and coming back also throws out your changes, though it does remain in the NoteEdit activity. Both "Back" and "Home" cause the onPause message to trigger, and both cause onResume to trigger (either from clicking on the item in the "Back" case, or by going back into the app in the "Home" case).
Is there a way to have these two events handle saving the state differently? Is it possible to have the Home button store the state (temporarily), while not having the Back button do it?
Thanks in advance!

You need to define an onSaveInstanceState method, but instead of saving to the DB (as in the Notepad sample), save your Activity's state to the Bundle. You then need to recover from the saved state in your onCreate when the passed in Bundle is non-null.

How to handle that the application is minimized by HOME button

An issue has appeared a few days ago.
I have an application that listen for GPS location. The listener is a background service that works all the time, this service saves data in application level and each activity reads this data. So, when i press back button i am able to catch this event and i can stop the service, but when i press HOME button the service is still working although the application is in background mode and this consumes battery, because the GPS always works. How can i handle this event? I do want to stop all services when the user presses HOME button and start them again when user gets back.
10x

It sounds like you're catching the back button either via an onKey... method or in onStop. You should place your code in the onPause() method to ensure it's used whenever the app gets backgrounded.

You can not handle home button events in your Android application. Google has made it for internal use only.
LINK 1
LINK 2

#Override
protected void onUserLeaveHint()
{
// When user presses home page
Log.v(TAG, "Home Button Pressed");
super.onUserLeaveHint();
}

You could create a OnKeyListener, and check if the pressed key was Home. I never tried it, though.

create a custom activity called customActivity extends Activity now override method(in customActivity) to catch home button event and stop your service(create & start service in application class). Now extends customActivity instead of Activity for any activity_class.

Long press the HOME button, it will enlist the running process, select the one you want and then exit it gracefully.
OR
From Home -> settings -> application -> manage application
you can kill the unwanted process.