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My app is not working properly when screen is rotated

I am creating an app on android studio. The app is working fine but whenever I rotate the screen, the layout is changing, the items on the screen are getting overlapped and sometimes the app restarts.
What are the possible solutions? Is preventing the screen from rotation a good option? Please help. Thanks in advance.

You need to set orientation in AndroidMenifest.xml.Use keyboardHidden attribute if you are getting any issue in keyboard.

You can set you activity's screen orientation to portrait, by this your activity will never rotate, but if you want to support landscape version then you have to create a landscape layout as well and put the layout in layout-landscape folder, but you have to take care of your data also.
Choice is yours

You can prevent your activity to recreate when orientation changes. Just add this in your activity tag in Manifest file.
<activity
android:name=".YOUR_ACTIVITY_NAME"
android:configChanges="keyboardHidden|orientation|screenSize" />

Android Activites start from the beginning when you rotate a device. So your Activity Lifecycle methods like
onCreate(), onStart(), onResume()
will be called again.
There are two possible solutions, the first one is by Rob here.
<activity
android:name=".ACTIVITY"
android:configChanges="keyboardHidden|orientation|screenSize" />
This will handle the orientation changes itself.
Another solution is to create different layout types in different layout folders. The folders will be
layout-land, layout-sw600dp-land(for 7inch tablets) and layout-sw720dp-land(for 10inch tablets)
So when you rotate a device, the layouts in this folders will be automatically inflated by the system. There will be cases like when you want to preserve the current state of the activity, for this refer to this link

No, preventing the orientation to be landscape is not a good solution. Many tablets are landscape-only, and your app won't display correctly on those.
The correct thing to do is to save your state in onSaveInstanceState() and then read it in onCreate() when the activity is re-created (the savedInstanceState variable will not be null). For this to work, the data that you are saving must be Serializable or Parcelable.
If you want to save non-serializable data or you have something running in the background, you can use a Fragment with setRetainInstance(true); and no layout. See this link.
The view will be created again, yes, but you will set the saved values so that it will look as it was before the rotation.

How to enable rotation on android on same activity?

I am sorry, this question has been asked probably thousand times over, but I do not find the correct words how to ask this question.
I have an activity in android. When I turn the screen at 90 degrees, it looks like the current activity is completely destroyed and a new activity is initiated. Is that correct?
But if I have showed some data in one orientation, I want to show the exact same data in the other orientation? Is there some SIMPLE way to achieve this? That the activity just remains, but shows the layout with the SAME data from the SAME activity in the other orientation?

there is an easy way to save your time, if your project api level is upper than Android 3.2 (API level 13) add this code into your activity in manifest:
android:configChanges="keyboardHidden|orientation"
Update: this also can help:
android:configChanges="keyboardHidden|orientation|screenSize"

Yes whenever an activity changes its rotation it is destroyed and recreated. and the same android uses same layout and roughly shows it into landscape mode.
You can make a new folder layout folders name layout-land.
layout-land may contain the same layout as in layout folder and the views can be tweeked according to the landscape orientation requirments

Another way would be to store all your information in savedInstanceState and restore it from there in onCreate(). Or use a Fragment with setRetainInstance(true) to store your information in.

Device Orientation Change doesnt change layout

I have alternative layouts in my layout-normal-land and layout-normal-port folders and they are correctly invoked by the system according to if I hold the device in land or port at start. My problem is, when I rotate the device AFTER I have launched the app, it tries to somehow adapt the already displayed view to the new situation, creating a mess.
How can I tell the system it should switch to the alternate layout during execution?
Have been experimenting around and found that when I dont have android:configChanges="keyboardHidden|orientation" , oncreate gets called again, which gives the correct layout, but its not what I want to have. I dont think this is normal, is it? Maybe a question of bug in Android (2.3.3.)?

By including
android:configChanges="orientation"
in your manifest you are saying you want to handle orientation changes yourself. You should remove it if you want the system to handle it for you.
The automatic handling works extremely well. You should only override it if you have a specific reason for doing so.
In normal operation (without the above manifest entry), an orientation switch causes the current activity to be closed and then re-opened in its new orientation reloading all resources and layouts from the currently active resource folders. The process follows what is known as the "Activity Lifecycle".
If you include the above manifest entry, you are saying, "I will handle all changes myself. Do not close my activity" so it is then your responsibility to remove all unwanted layouts from the activity and replace them with the layouts you now require for the current orientation.

Do you already use an OrientationListener?
If no:
http://developer.android.com/reference/android/view/OrientationEventListener.html#onOrientationChanged(int)
the listener should detect orientation changes.
Then you call setContentView (R.layout.name_of_layout) in your Activity class.
Hope this helps.

do you have android:configChanges="orientation" in your manifest on that activity? That will prevent android from automatically changing your layout.

May be obvious, but:
Within the res folder make sure you have the folders labelled "layout" and "layout-land".
Portrait and landscape .xml files must have the same filename.

I have run into the same problem, and I did not have android:configChanges="orientation" in my manifest.
However I did have [Activity(ConfigurationChanges = ConfigChanges.Orientation)] in my mainactivity. That seemed to be another way to override the automatic orientation handling.

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.
update the manifest to handle the orientation.
android:configChanges="orientation|screenSize"
add this code
#Override
public void onConfigurationChanged(Configuration newConfig) {
// TODO Auto-generated method stub
super.onConfigurationChanged(newConfig);
setContentView(R.layout.activity_main);
}

How do you create an app that only allows horizontal orientation?

I'm currently creating a side-scroller style game for my final year project for my degree.
I'm just wondering how you make the menu designed for when the phone is in horizontal orientation display, even when the phone is held in it's vertical orientation?
i.e. I want the user to know that the game has to be played with the phone in it's horizontal orientation and want the menu's to only display in the horizontal orientation.
Many thanks in advance.

Add the following attribute to your activity in your AndroidManifest.xml:
android:screenOrientation="landscape"

Well, I didn't get your question right,
but if you are defining your menu via xml
create a new folder in your res folder named
for layout changes:
layout_land
for horizontal specific menu:
xml-land
for horizontal specific drawables:
drawable-land
and define your menu,layout and drawable changes there.
Further you can tell android framework that you want to handle rotation changes:
by adding to your manifest(AndroidManifest.xml) activity child
android:configChanges="keyboardHidden|orientation"
android:screenOrientation="landscape"
Comment exactly what you want.
Cheers!

Just complementing on other's answers
There are some different types of landscape and I think the best one is:
android:screenOrientation="userLandscape"
because it lets the user switch to landscape or reverse landscape using the device's sensor, or the user can block the swithing if he decides to.
I found that removing some basic controls of the user is quite annoying and should only be used if really necessary.
If you want to checkout other possible orientations just go here