Android Back button code never executed

Question

I have the following code in my Activity. I have Breakpoints set to all of these methods. When I press the Menu button, it enters onKeyDown and onKeyUp. When I press the back button, the app closes and phone goes back to home screen without passing any of my breakpoints.

EDIT: This could should work according to most sources:

@Override
public void onBackPressed() {
    SwitchToMenuState();
}

However, it doesn't. I have tried all permutations of the following code blocks, and neither of them ever get called:

@Override
public void finish()
{
    SwitchToMenuState();
}   

public boolean onKeyUp(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        SwitchToMenuState();
    }
    return true;
}

public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        SwitchToMenuState();
    }
    return true;
}

I am using Android 2.3 and Processing, although it doesn't seem to be related to Processing at all. Eclipse tells me that I am overriding android.app.Activity.onBackPressed.

Most likely onBackPressed() is indeed being called, but there's something up with your SwitchToMenuState() method. Maybe you have some incorrect condition checking in there or something. Mind posting that up? — Jade Byfield, Dec 01 '12 at 18:48
I have a breakpoint on the method, so it is not being called (since the breakpoints on other methods do work, when other buttons are pressed). I have tried putting Log.d("myTag","OnBackPressed Registered"); in the onBackPressed method, without luck. — joon, Dec 01 '12 at 19:52

score 1 · Answer 1 · answered Dec 01 '12 at 20:31

All you need is onKeyDown

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {

        //Your code here

            return true;
    }
    return super.onKeyDown(keyCode, event);
}

I think it's because you're not returning the super part. This works for me, you don't need the onbackpressed or onkeyup etc.

score 0 · Answer 2 · answered Dec 01 '12 at 17:10

0

Use onKeyDown in android 1.x onBackPressed in android 2.x

And use only either of them, not both

answered Dec 01 '12 at 17:10

cjds

8,268
10
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84

I have tried either individually. I am on Android 2.3. The code never enters the onBackPressed method. Eclipse confirms that I am overriding onBackPressed from android.app.Activity.onBackPressed. – joon Dec 01 '12 at 18:39
unless you're adding super.onBackPressed() to the top of the method it should run. Be sure the onKeyDown method stub isn't there because even that will prevent a call to onBackPressed unless super.onKeyDown(....,...) is called – cjds Dec 02 '12 at 03:03
Maybe this will help http://android-developers.blogspot.in/2009/12/back-and-other-hard-keys-three-stories.html – cjds Dec 02 '12 at 03:04

score -1 · Answer 3 · answered Dec 01 '12 at 16:46

-1

when you press back, if haven't a activity before this activity, your app will close. You can start use : startActivity(intent);

answered Dec 01 '12 at 16:46

Nguyễn Anh Quế

243
2
10

I'm not sure I fully understand what you mean. My 'main' class extends Activity, and this is where that code is (which works for all other buttons except back). – joon Dec 01 '12 at 16:53

Android Back button code never executed

3 Answers3

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