How to restrict tablet screen orientation?

Question

I want to restrict my tablet to launch at specific screen orientation like landscape. I'm taking here about the whole tablet not a specific app, and for sure I'm not taking about locking off the Auto Rotate in the tablet after it launches, I'm taking about restricting the tablet to launch initially at landscape|protrait.

Answer 1

found the answer, an app that will run just one time.

create an app and add a permission to it's manifest to write_settings & listen-to-boot :

<uses-permission android:name="android.permission.WRITE_SETTINGS" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

then make a receiver class which extends BroadcastReceivertype, with the fowlloing permissions:

    <receiver android:enabled="true" android:exported="true" 
        android:name="com.example.BootCompletedReceiver"
        android:permission="android.permission.RECEIVE_BOOT_COMPLETED">
        <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                <action android:name="android.intent.action.QUICKBOOT_POWERON" />
                <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </receiver>

then in the onReceive() method of the receiver class:

ContentResolver contentResolver = context.getContentResolver();
        //To handle device rotation 
        Settings.System.putInt(contentResolver, Settings.System.ACCELEROMETER_ROTATION, 0);
        Settings.System.putInt(contentResolver, Settings.System.USER_ROTATION, Surface.ROTATION_90); // 0 for default, then 90, 180, 270

Then run this app just one time to write that permissions to the system, and then you don't need it again.