Activity orientation changes automatically on Android

Question

I\'m developing a mobile application based on Android with minSdkVersion=15. I would like to support both orientations for tablets and only portrait for smartph

Answer 1

In your base activity you can put something like this:

/*  Device types. */
static int MOBILE_DEVICE = 0;
static int SEVEN_INCH_TABLET = 1;
static int TEN_INCH_TABLET = 2;

private static int deviceType = MOBILE_DEVICE;
private boolean deviceTypeDetermined = false;


@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
@Override
protected void onCreate(Bundle savedInstanceState) {

    if ( ! deviceTypeDetermined) setDeviceType();

    /* Screen rotation only for tablets. */
    if (getDeviceType() < SEVEN_INCH_TABLET) {
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        lockScreenOrientation();

    ......
}



// ---------------------------------------------------------------------------------------------
static int getDeviceType() {
    return deviceType;
}
// ---------------------------------------------------------------------------------------------


// ---------------------------------------------------------------------------------------------
private void setDeviceTypeDetermined() {
    this.deviceTypeDetermined = true;
}
// ---------------------------------------------------------------------------------------------


// ---------------------------------------------------------------------------------------------
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
private void setDeviceType() {

    /*
        Let's invest on what kind of screen our APP is invited...

        We only make a difference in 10", 7" tablets and the rest...
    */

    Display mDisplay = getWindowManager().getDefaultDisplay();
    Point mScreenResolution = new Point();

    mDisplay.getRealSize(mScreenResolution);

    int mWidthPixels = mScreenResolution.x;
    int mHeightPixels = mScreenResolution.y;

    DisplayMetrics mMetrics = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(mMetrics);

    float mWidthDpi = mMetrics.xdpi;
    float mHeightDpi = mMetrics.ydpi;

    float mWidthInches = mWidthPixels / mWidthDpi;
    float mHeightInches = mHeightPixels / mHeightDpi;



    double mDiagonalInches = Math.sqrt(
            (mWidthInches * mWidthInches)
                    + (mHeightInches * mHeightInches));


    if (mDiagonalInches >= 9) {

        /*
            A tablet with 8" x 5" is called a 10", but it is in fact
            9.43398". Interesting that this kind of things happens in
            the world of informatics.... ;)
        */

        MyBaseAppCompatActivity.deviceType = TEN_INCH_TABLET;
    }

    else if (mDiagonalInches >= 7) {
        MyBaseAppCompatActivity.deviceType = SEVEN_INCH_TABLET;
    }

    else
    {
        MyBaseAppCompatActivity.deviceType = MOBILE_DEVICE;
    }


    setDeviceTypeDetermined();
}
// ---------------------------------------------------------------------------------------------


// ---------------------------------------------------------------------------------------------
void lockScreenOrientation() {

    /*  Screen rotation only for tablets. */
    if (deviceType < SEVEN_INCH_TABLET ) return;

    setRequestedOrientation(getResources().getConfiguration().orientation);
}
// ---------------------------------------------------------------------------------------------


// ---------------------------------------------------------------------------------------------
void unlockScreenOrientation() {

    /*  Screen rotation only for tablets. */
    if (deviceType < SEVEN_INCH_TABLET ) return;

    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);
}
// ---------------------------------------------------------------------------------------------

And in your activities in the onCreate:

// ---------------------------------------------------------------------------------------------
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR1)
protected void onCreate(Bundle savedInstanceState) {
    // -----------------------------------------------------------------------------------------
    super.onCreate(savedInstanceState);

    if (getDeviceType() >= SEVEN_INCH_TABLET) unlockScreenOrientation();

    setContentView(R.layout.main_activity);

    .........

// ---------------------------------------------------------------------------------------------