Develop Reference

Why when rotating the phone from portrait into landscape, does the app lose all data?

I'm trying to create an app in Android, using Eclipse ADT and I use a HTC phone. Here's the problem: after running the app on the phone from Eclipse, I add elements to my ListView and everything is fine, BUT when I turn the device in landscape mode the hole app seems like it restart, there's no more records inside. It's like new. Any ideas why and how I can solve this problem? Please don't tell me to deactivate the screen rotate option from phone settings.

This is the way android handles orientation changes. It reloads your whole activity. The normal way to handle this situation is to save the state of your activity in onPause() and then retrieve it back in onCreate().
Here is more information on the android activity lifecycle:
http://developer.android.com/reference/android/app/Activity.html#ActivityLifecycle
EDIT:
You should implement onPause() anyway, because it will also be called if the phone rings in the middle of running your activity. In this case, when the user comes back from the call your activity will possibly be reloaded from scratch again and the user will lose their state.

There is a similar question here.
Basically you application is restarted. You can either force your application to portrait or follow the steps here to find out how to handle it properly.

I made answer over here about this sort of thing.
Please don't tell me to deactivate the screen rotate option from phone settings.
I'm not sure if you meant the following, but here's a solution:
Add android:configChanges="orientation|screenSize" to your <activity tag, which is in your AndroidManifest.xml, like so:
<activity
android:name="activity_name"
android:label="#string/app_name"
android:configChanges="orientation|screenSize" />
This will prevent the activity from being destroyed when the orientation is changed, like it usually would. There are other ways to fix this as well. Please leave a comment if this is not your desired solution. I can make up another.

How can i stop orientation change in android table?

Hi i am developing android application in tablet version. Here i am facing problem with orientation so i want to make my application in portrait mode only. For that i Used attribute like below snippet for each and every activity in my application.
android:configChanges="keyboard|orientation|keyboardHidden"
android:screenOrientation="portrait"
Application is running perfectly while testing in portrait mode. But it is not good while testing application with tablet physical position with landscape. It is first going to landscape then immediately going to portrait.
I used programmatically making the activity in portrait but no effect. Please provide me any help.
Here is my programmatic orientation fix
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
I tested in Motorolo device
Please suggest me to avoid my application going to landscape.

Try this...
<activity
android:label="#string/app_name"
android:name="abc.xyz.dd.MainScreen"
android:screenOrientation="portrait"
android:configChanges="keyboardHidden|orientation">
By adding this in manifest file it will prevent from changing to landscape mode.

Finally i find the reason why orientation changes are occurring in android tablet. In ICS (version 4.0+) the tablet have the option like "Don't keep activities" in settings>> Developer tools>>
If the user checked that option the paused activity will killed and created when it is call again. what i mean the activity won't go for onPause() state it will go for onDestroy() and it will created again when press on back key. So the orientation behavior is different.
I did not get the idea how to handle it from our android code

Air Android app crashes when phone changes orientation

... or at various settings in the app xml (<appName>-app.xml or application.xml) when holding the phone in Portrait-orientation instead of landscape-orientation.
Depending on various settings our testphone, Samsung Galaxy s3, crashes right at launch when we do debug on the phone in FlashDevelop. Actually we are debugging with a release so we don't get any traces, but all the same we are running the app on the phone.
For instance if we set
<aspectRatio>landscape</aspectRatio>
<autoOrients>true</autoOrients>
and hold the phone in landscape orientation when we start the debug, then the app runs as should be.
However if we with the same settings hold the phone in portrait orientation when starting the debug, then the app crashes on startup.
The exact same happens if we set auto orient to false and/or remove the Aspect Ratio.
It also doesn't matter what we set stage.scaleMode to in my Main class... or at least i've not been able to figure out any combo with aspectRatio/autoOrients/ that works.
I read something at a glance here at Stack Overflow in another thread about something that seemed similar was a bug in earlier Android versions, but that it should be fixed in ICS (which we have on the test devices).
And I may also have seen something at a glance about it being related to the virtual keyboard and to add some code in the xml Manifest at various actions..
Does anyone have a clue for sure please? :-)
edit:
The App is built to only ever be shown in Landscape orientation. It can't work in portrait.

I have also encountered same problem; app crashes everytime orientation changes. What I did was very simple:
FIRST, create two folders for your layout:
layout
layout-land
Then, put your portait layouts in layout and landscape layouts in layout-land.
This will do the trick. Hope you can get idea from my experience.

Handling orientation on lockscreen for an android app

Testing my application on my Galaxy S2 I have a problem whenever the screen is turned off and back on. My application is locked into landscape by the manifest. The lock screen forces the application into some weird orientation where it is rendering portrait but displaying it was landscape (as in the right 2/5 of my screen is black and the portrait rendering goes off the bottom). The application is also not responsive in this state. If I quickly hit home (or back) and recall the application it works perfect.
As well, if I use a different lock screen (tried with PowerAmp) it works flawlessly.
So can anyone help me understand why this is screwing up and how to fix the orientation whenever this happens?
I can avoid this by avoiding the lock screen through a flag (window.addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD)) but I don't have any other reason to avoid a lock screen and would like to know what is happening.

This sound like a problem that is unique to the S2. Have you tried your app on the emulator or any other devices. It may just be that the S2 implements some part of android incorrectly.

To handle the orientation problem in your application try to use this for your activity like this
<activity android:configchanges="orientation|keyboardHidden" />
in your Android Manfiest file.

How can I stop auto screen rotation in my Android app when unlocking the phone from standby

I have an android application that I want to always be running in landscape mode.
I have the following code implemented to keep the app in landscape mode all the time:
inside my activity in the Application Manifest
android:screenOrientation="landscape"
This seems to launch and keep the application in landscape view for the whole duration of the application. Perfect!
However, if I have the app running on my HTC Aria (Android 2.1) and the phone locks, if I unlock the phone, I see the application for probably half a second and it's in portrait orientation and then quickly switches back to landscape mode. It is quite frustrating because all of my views are jumbled around and it looks unprofessional as you can imagine. This happens in both the emulator and on my real phone.
Does anyone know how to stop the application from temporarily rotating when the phone is unlocked?
Additions:
I have tried overriding onConfigurationChanged() but with no success.
I have also tried putting setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); into the onResume() but the app still shows as the incorrect orientation for a split second when the phone is unlocked.

Try setting the orientation in the manifest file. it might just work.

After looking at many other apps that are made for landscape orientation only, I can see that their apps don't freeze their orientation after standby either. I have a feeling that this is a limitation of the phone, and that all apps will switch to a portrait orientation when the phone is locked. If all apps have this "problem" then I think it is acceptable not to fix.
Please post if you have found out there is a way to stop the forced portrait orientation.

the app still shows as the incorrect orientation for a split second when the phone is unlocked.
Did you move setContentView(R.layout.main) to the onResume, AFTER where you put your orientation code? I would try setting the orientation, then the setContentView()