How to remove the delay when opening an Activity with a DrawerLayout?

Question

I have an activity with a DrawerLayout but whenever it opens there is a delay like a split-second where the screen is white then my screen is drawn.

This happens after the Transition finishes. So it sort of looks like the screen animation transition is jumping.

I tried putting this on my OnCreate after binding the views with ButterKnife but it did nothing.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        postponeEnterTransition();
        drawerLayout.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
            @TargetApi(Build.VERSION_CODES.LOLLIPOP)
            public boolean onPreDraw() {
                drawerLayout.getViewTreeObserver().removeOnPreDrawListener(this);
                startPostponedEnterTransition();
                return true;
            }
        });
    }

Yes I am optimizing it for Lollipop, and for pre-Lollipop devices I am jsut using overridePendingTransitionsand it works fine. My problem is only on Lollipop devices.

Btw, my Enter and Exit transitions are both fade_in_outdefined in xml and specified in styles

<style name="AppTheme" parent="Theme.AppCompat.Light">
    <item name="colorAccent">@color/pink</item>
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
    <item name="android:windowDrawsSystemBarBackgrounds">true</item>
    <item name="android:windowActivityTransitions">true</item>
    <item name="android:windowContentTransitions">true</item>
    <!-- specify enter and exit transitions -->
    <!-- options are: explode, slide, fade -->
    <item name="android:windowEnterTransition">@transition/fade_in_out_transition</item>
    <item name="android:windowExitTransition">@transition/fade_in_out_transition</item>

    <!-- specify shared element transitions -->
    <item name="android:windowSharedElementEnterTransition">@transition/change_clip_bounds</item>
    <item name="android:windowSharedElementExitTransition">@transition/change_clip_bounds</item>
    <item name="android:windowSoftInputMode">stateAlwaysHidden|adjustResize</item>
</style>

Answer 1

I finally found a solution to this. I don't know why or how it worked out but I just know that it removed the delay in the animations. I added a handler in the OnCreate of the activity that would run the other statements for setting up, i.e. adding the initial fragment into view, after 300ms

Handler mHandler = new Handler();
mHandler.postDelayed(new Runnable() {
    @Override
    public void run() {
        switchFragment();
    }
}, 300);