Android Constraint Layout onMeasure not seeing soft Keyboard

Question

Ok so I'm trying to create an Event hook to notify me when the soft Keyboard is shown or hidden.

I've sub-classed the Constraint Layout as follows:

public class MyConstraintLayout extends ConstraintLayout
{
    //public static final String KEYBOARD_STATE = "KEYBOARD_STATE", SHOWN = "SHOWN", HIDDEN = "HIDDEN";
    public static final String ACTION_KEYBOARD_SHOWN = "KEYBOARD_SHOWN";
    public static final String ACTION_KEYBOARD_HIDDEN = "KEYBOARD_HIDDEN";
    private LocalBroadcastManager localBroadcastManager;
    private Intent keyboardShown, keyboardHidden;
    private boolean shown = false;

    public MyConstraintLayout(Context context)
    {
        super(context);
        init(context);
    }

    public MyConstraintLayout(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        init(context);
    }

    public MyConstraintLayout(Context context, AttributeSet attrs, int defStyleAttr)
    {
        super(context, attrs, defStyleAttr);
        init(context);
    }

    private void init(Context context)
    {
        localBroadcastManager = LocalBroadcastManager.getInstance(context);
        keyboardShown = new Intent(ACTION_KEYBOARD_SHOWN);
        keyboardHidden = new Intent(ACTION_KEYBOARD_HIDDEN);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
    {
        //Log.d("Search Layout", "Handling Keyboard Window shown");
        final int proposedHeight = MeasureSpec.getSize(heightMeasureSpec);
        final int actualHeight = getHeight();

        Log.v("MyConstraintLayout", "onMeasure: actualHeight="+actualHeight+", proposedHeight="+proposedHeight);

        if(actualHeight > proposedHeight)
        {
            // Keyboard is shown
            if(!shown)
            {
                shown = true;
                localBroadcastManager.sendBroadcast(keyboardShown);
            }
        }
        else
        {
            // Keyboard is hidden
            if(shown)
            {
                shown = false;
                localBroadcastManager.sendBroadcast(keyboardHidden);
            }
        }
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }
}

but it seems that the Layout is not seeing the keyboard at all since the Log output is exactly the same when the keyboard gets shown as when it gets removed. Here is the Log output: When Keyboard gets shown:

V/MyConstraintLayout: onMeasure: actualHeight=1120, proposedHeight=1280
V/MyConstraintLayout: onMeasure: actualHeight=1120, proposedHeight=1120

And when the keyboard gets Hidden

V/MyConstraintLayout: onMeasure: actualHeight=1120, proposedHeight=1280
V/MyConstraintLayout: onMeasure: actualHeight=1120, proposedHeight=1120

I'm testing on a Samsung J500f running Android 6.0.1.

so I have 2 Questions really:
1 - Why is the Layout not seeing the keyboard?
2 - Why is the event fired twice with proposedHeight flipfloping between 1120 and 1280?

Also to note, It was firing 4 times(still just flipfloping between the same values) until I added android:windowSoftInputMode="adjustPan" to the Manifest.xml.