Why not use always android:configChanges="keyboardHidden|orientation"?

I was wondering why not use android:configChanges="keyboardHidden|orientation" in every (almost every ;)) activity?

Goods:

• no need to worry about your activity been rotated
• it's faster

Not so nice:

• need to change your layouts if they are depending on screen size (e.g. layouts with two columns or so)

Bad:

• no flexible way to have different layouts on different orientation
• not so good when using fragments

But if we don't use different layouts, why not?

Quick Background

By default, when certain key configuration changes happen on Android (a common example is an orientation change), Android fully restarts the running Activity to help it adjust to such changes.

When you define android:configChanges="keyboardHidden|orientation" in your AndroidManifest, you are telling Android: "Please don't do the default reset when the keyboard is pulled out, or the phone is rotated; I want to handle this myself. Yes, I know what I'm doing"

Is this a good thing? We shall soon see...

No worries?

One of the pros you start with is that there is:

> no need to worry about your activity been rotated

In many cases, people mistakenly believe that when they have an error that is being generated by an orientation change ("rotation"), they can simply fix it by putting in android:configChanges="keyboardHidden|orientation".

However, android:configChanges="keyboardHidden|orientation" is nothing more than a bandaid. In truth, there are many ways a configuration change can be triggered. For example, if the user selects a new language (i.e. the locale has changed), your activity will be restarted in the same way it does by an orientation change. If you want you can view a list of all the different types of config changes.

Edit: More importantly, though, as hackbod points out in the comments, your activity will also be restarted when your app is in the background and Android decides to free up some memory by killing it. When the user comes back to your app, Android will attempt to restart the activity in the same way it does if there was some other configuration change. If you can't handle that - the user will not be happy...

In other words, using android:configChanges="keyboardHidden|orientation" is not a solution for your "worries." The right way is to code your activities so that they are happy with any restart Android throws at them. This is a good practice that will help you down the road, so get used to it.

So when should I use it?

As you mentioned there is a distinct advantage. Overwriting the default configuration change for a rotation by handling it yourself will speed things up. However, this speed does come with a price of convenience.

To put it simply, if you use the same layout for both portrait and landscape you're in good shape by doing the overwrite. Instead of a full-blown reload of the activity, the views will simply shift around to fill the remaining space.

However, if for some reason you use a different layout when the device is in landscape, the fact that Android reloads your Activity is good because it will then load up the correct layout. [If you use the override on such an Activity, and want to do some magical re-layout at runtime... well, good luck - it's far from simple]

Quick Summary

By all means, if android:configChanges="keyboardHidden|orientation" is right for you, then use it. But PLEASE be sure to test what happens when something changes, because an orientation change is not the only way a full Activity restart can be triggered.

From my point of view: If the layout is the same in both landscape and portrait mode - you might aswell disable one of the two in your app.

The reason why I state this is that I as a user expect the app to provide me with some benefit, when I change orientation. If it doesn't matter how I hold my phone, then I don't need the choice.

Take for instance an app where you have a ListView, and upon clicking a ListItem you want to be shown a detailed view for that item. In landscape you would od this by dividing the screen in two, having the ListView on the left and the detailed view on the right. In Portrait you would have the list in one screen and then change the screen to the detailed view when a ListItem is selected. In that case orientation change makes sense as well as different layouts.

I don see why.... occasional restarts are ok in my opinion... configChanges handles most cases for me... well maybe in some types of applications this can be problem but it depends really on type of app and how you restore state when app restarts... When one of my app restarts user is logged back and last activity opens by my code and user jus loses some steps to go back where he was but not big deal.. In other some state is always persisted and some state is always restored on restart. When activity restarted it had to be that app have not been used or something... so no problem at all... In game for example this can be problem maybe or in some other type of app I don't know...

I say that when you do it this way applications just works fine under normal circumstances. And code is much more readable without ton of logic needed for saving and restoring where u just can make new bugs and have to maintain it all the time... sure if android gets out of power and kill you application window it lose the context and starts again, but this happen just in special situations and on newer devices I belive this is more and more rare...

So kill me, but I use this across applications quite successfully... android:configChanges="locale|keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" But I understand that for some special kind of applications it may be not good way but most of apps can live with this just OK.

Yeah I think pausing will make it quicker than releasing the player. Still have the pause though.

Have now found a solution that won't pause the song.

State in the manifest that you will handle the config change for screen orientation and then use the onConfigurationChanged method to load the layout file. By doing this in logCat I can see onPause, onCreate & onResume aren't called, and therefore the song isn't paused.

1. update the manifest to handle the orientation.

    android:configChanges="orientation|screenSize"
    
   

2. add this code

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
    	// TODO Auto-generated method stub		
    	super.onConfigurationChanged(newConfig);		
    	setContentView(R.layout.activity_main);
    }