How do I force horizontal orientation on Android activity?

Open the AndroidManifest.xml file and set the screenOrientation attribute to “landscape” for the activity you want to force horizontal orientation. For example:

<activity
    android:name=".YourActivity"
    android:screenOrientation="landscape">
</activity>

In the activity’s Java/Kotlin file, you can also programmatically enforce the landscape orientation by adding the following code in the onCreate() method:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
    setContentView(R.layout.activity_main);
}