Develop Reference

How to disable resizeableActivity without disabling the support of foldable devices

In the android developers site they say:
If you set resizeableActivity=false to disable multi-window mode but
still want to support app continuity, add the following meta-data to
the manifest of your element:
<meta-data
android:name="android.supports_size_changes" android:value="true" />
If the value is true and the user attempts to fold or unfold a device,
the activity will apply any changed configurations in a way that
supports changes in window sizes.
So I did as they said but the activity isn't automatically resumed when I test it in the emulator.
here is my code:
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:resizeableActivity="false"
android:roundIcon="#mipmap/ic_launcher_round"
android:theme="#style/MaterialTheme">
<meta-data
android:name="android.supports_size_changes" android:value="true" />
</application>
Did I do anything wrong?

How to Lock Android App's Orientation to Portrait in Phones and Landscape in Tablets?

I am developing an Android app whose orientation I don't want changed to landscape mode when the user rotates the device. Also, I want the locked orientation to be portrait mode on phones and landscape mode on tablets. Can this be achieved, if yes how? Thanks.

You just have to define the property below inside the activity element in your AndroidManifest.xml file. It will restrict your orientation to portrait.
android:screenOrientation="portrait"
Example:
<activity
android:name="com.example.demo_spinner.MainActivity"
android:label="#string/app_name"
android:screenOrientation="portrait" >
</activity>
if you want this to apply to the whole app define the property below inside the application tag like so:
<application>
android:screenOrientation="sensorPortrait"
</application>
Additionaly, as per Eduard Luca's comment below, you can also use screenOrientation="sensorPortrait" if you want to enable rotation by 180 degrees.

You have to add the android:screenOrientation="portrait" directive in your AndroidManifest.xml. This is to be done in your <activity> tag.
In addition, the Android Developers guide states that :
[...] you should also explicitly declare that your application requires
either portrait or landscape orientation with the
element. For example, <uses-feature android:name="android.hardware.screen.portrait" />.

I can see you have accepted an answer which doesn't solve your problem entirely:
android:screenOrientation="portrait"
This will force your app to be portrait on both phones and tablets.
You can have the app forced in the device's "preferred" orientation by using
android:screenOrientation="nosensor"
This will lead to forcing your app to portrait on most phones phones and landscape on tablets.
There are many phones with keypads which were designed for landscape mode. Forcing your app to portrait can make it almost unusable on such devices. Android is recently migrating to other types of devices as well. It is best to just let the device choose the preferred orientation.

It might be.. you have to identify it is tablet or phone by programmatically...
First check device is phone or tablet
Determine if the device is a smartphone or tablet?
Tablet or Phone - Android
Then......
if(isTablet)
{
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}else
{
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

<activity android:name=".yourActivity"
android:screenOrientation="portrait" ... />
add to main activity and add
android:configChanges="keyboardHidden"
to keep your program from changing mode when keyboard is called.

Set the Screen orientation to portrait in Manifest file under the activity Tag.
Here the example
You need to enter in every Activity
Add The Following Lines in Activity
for portrait
android:screenOrientation="portrait"
tools:ignore="LockedOrientationActivity"
for landscape
android:screenOrientation="landscape"
tools:ignore="LockedOrientationActivity"
Here The Example of MainActivity
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="org.thcb.app">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity"
android:screenOrientation="portrait"
tools:ignore="LockedOrientationActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".MainActivity2"
android:screenOrientation="landscape"
tools:ignore="LockedOrientationActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

Set the Screen orientation to portrait in Manifest file under the activity Tag.

android:screenOrientation="locked"
in <application> for all app
in <activity> for actual activity

I would like to add to Bhavesh's answer. The problem is that if users keep the phone in landscape mode and run the app it will first go to landscape mode since it's based on sensor in manifest and will then immediately switch to portrait mode in phones because of the code in onCreate. To solve this problem below approach worked for me.
1 Declare locked orientation in manifest for activity android:screenOrientation="locked"
<activity
android:name=".overview.OverviewActivity"
android:screenOrientation="locked" />
2 Check for tablet or phone in actiivty or base activity
override fun onCreate(savedInstanceState: Bundle?) {
//check if the device is a tablet or a phone and set the orientation accordingly
handleOrientationConfiguration()
super.onCreate(savedInstanceState)
}
/**
* This function has to be called before anything else in order to inform the system about
* expected orientation configuration based on if it is a phone or a tablet
*/
private fun handleOrientationConfiguration() {
requestedOrientation = if (UIUtils.isTablet(this).not()) {
ActivityInfo.SCREEN_ORIENTATION_PORTRAIT
} else {
ActivityInfo.SCREEN_ORIENTATION_SENSOR
}
}
UIUtils.kt
fun isTablet(context: Context): Boolean {
return context.resources.configuration.smallestScreenWidthDp >= 600
}
That's it, it will launch the app in the locked mode so that if you are on phone it will be always portraited and if you are on a tablet it will rotate based on the orientation of the device. This way it will eliminate the issue on phones where it switches between landscape and portrait at the start.
Read more here about the locked mode below
https://developer.android.com/guide/topics/manifest/activity-element

Just Add:
android:screenOrientation="portrait"
in "AndroidManifest.xml" :
<activity
android:screenOrientation="portrait"
android:name=".MainActivity"
android:label="#string/app_name">
</activity>

configChanges not recognized by TabHost?

I have a pretty big problem with my TabHost. Although I have declared all of my Activities (Including my TabHost Activity) to ignore orientation and keyboardHidden, if I flip my Phone (Android 4.0) It still recreates the activity.
Here is a shortened version of my Manifest:
<application
android:icon="#drawable/icon"
android:label="#string/app_name" >
<uses-library android:name="com.google.android.maps" />
<activity
android:name=".TabHost"
android:configChanges="orientation|keyboardHidden"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".Activity1"
android:configChanges="orientation|keyboardHidden"
android:label="#string/app_name" />
<activity
android:name=".Activity2"
android:configChanges="orientation|keyboardHidden"
android:label="#string/app_name" />
<activity
android:name=".Activity3"
android:configChanges="orientation|keyboardHidden"
android:label="#string/app_name" />
</application>
I don't think that the code of the activities would help?!
If it would however, let me know and I'll post it too.
Kind regards

if you are trying to stop the rotation of the screen use following code in your AndroidManifest.xml for each activity.
android:screenOrientation="nosensor"
UPDATE
According to API when using android:configChanges="orientation|keyboardHidden"
"orientation"
The screen orientation has changed — the user has rotated the device.
Note: If your application targets API level 13 or higher (as declared by the minSdkVersion and targetSdkVersion attributes), then you should also declare the "screenSize" configuration, because it also changes when a device switches between portrait and landscape orientations.
so, if you are targeting API level 13 or higher you gotta specify screen size also.

what is the meaning of this line in android samples?

what is the meaning of line
" and add the corresponding activity tags to the Android Manifest
file"
in the tab example on
http://developer.android.com/resources/tutorials/views/hello-tabwidget.html
under step 2.
i added the activity tags and it's still dont work
<activity android:name=".ArtistsActivity" android:label="#string/app_name" />
<activity android:name=".AlbumsActivity" android:label="#string/app_name" />
<activity android:name=".SongsActivity" android:label="#string/app_name" />

Every time you create a new activity in android, you have to add an activity tag to your android manifest file. Take a peek at this example,
http://developer.android.com/guide/topics/manifest/activity-element.html

It means add your activities to your manifest.
<activity android:name=".HelloTabWidget">

Android, how to not destroy the activity when I rotate the device?

I have an app that works only in portrait mode, and I have made the changes in my manifest file for every activity the orientation to be portrait. But when I rotate the device, the activity recreates again.
How to not destroy the activity?

For API 12 and below: add
android:configChanges="orientation"
Add "screenSize" if you are targeting API 13 or above because whenever your orientation changes so does your screen size, otherwise new devices will continue to destroy your activity. See Egg's answer below for more information on using "screenSize"
android:configChanges="orientation|screenSize"
to your Activity in AndroidManifest.xml. This way your Activity wont be restarted automatically. See the documentation for more infos

From the official document flurin said,
Note: If your application targets API level 13 or higher (as declared
by the minSdkVersion and targetSdkVersion attributes), then you should
also declare the "screenSize" configuration, because it also changes
when a device switches between portrait and landscape orientations.
So if your app targets API level 13 or higher, you should set this config instead:
android:configChanges="orientation|screenSize"

The right solution is
android:configChanges="orientation|screenSize"
Android documentation:
The current available screen size has changed. This represents a change in the currently available size, relative to the current aspect ratio, so will change when the user switches between landscape and portrait. However, if your application targets API level 12 or lower, then your activity always handles this configuration change itself (this configuration change does not restart your activity, even when running on an Android 3.2 or higher device).*

I was messing this up for a little bit and then relized that inside the Manifest file I was putting the configChanges on the Application level and not on the Activity Level. Here is what the code looks like when it is correctly working for me.
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity"
android:configChanges="orientation|screenSize|keyboardHidden">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>

Now that Android supports split screen ("multi-window" in Android parlance), you'll probably want to add screenSize|smallestScreenSize|screenLayout|orientation as well. So to handle rotation and split screen you'll want something like this in android:configChanges
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity"
android:configChanges="orientation|screenSize|keyboardHidden|smallestScreenSize|screenLayout">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>

Look at this code in Floating Image. It has the most interesting way of handling screen rotation ever. http://code.google.com/p/floatingimage/source/browse/#svn/trunk/floatingimage/src/dk/nindroid/rss/orientation

write in manifest:
android:configChanges="orientation|screenSize|keyboardHidden"
and override this in activity that solved your problem:
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
}