android - Translucent/Transparent status bar + CoordinatorLayout + Toolbar + Fragment

Question

I have following setup:

• I'm using AppCompat
• MainActivity, that holds a fragment and has a toolbar, that's hiding when scrolling down
• Fragment with RecyclerView
• all views that should fit the screen have the according android:fitsSystemWindows="true" in the xml layout

The problem is, I can't get the statusbar transparent in this case. What I do is following:

1. Create the activity and call setContent

2. Then I try to adjust the activity to programmatically get a translucent toolbar like following:

   @TargetApi(Build.VERSION_CODES.LOLLIPOP)
   public void themeNavAndStatusBar(Activity activity)
   {
       if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP)
           return;
   
       Window w = activity.getWindow();
       w.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
       w.setFlags(
               WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION,
               WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
       w.setFlags(
               WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS,
               WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
       w.setNavigationBarColor(activity.getResources().getColor(android.R.color.transparent));
   
       w.setStatusBarColor(activity.getResources().getColor(android.R.color.transparent));
   }
   

3. Replace the placeholder in the activity (@+id/frame_container) with the fragment

The statusbar is solid colored in this case, and the views are not drawn underneath it... Why?

What I want

I want a toolbar, that is scrolled of the screen and hiding completely while the content underneath this toolbar should fitScreen and be drawn behind the transparent nav bar.

Layouts

Here's my main activity:

<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/clMain"
    android:fitsSystemWindows="true"
    android:background="?attr/main_background_color"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appBarLayout"
        android:fitsSystemWindows="true"
        android:background="@null"
        app:elevation="0dp"
        app:contentInsetLeft="0dp"
        app:contentInsetStart="0dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            android:elevation="4dp"
            android:theme="?actionBarThemeStyle"
            app:popupTheme="?actionBarPopupThemeStyle"
            app:layout_scrollFlags="scroll|enterAlways">

            <LinearLayout
                android:orientation="vertical"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content">

                <LinearLayout
                    android:orientation="horizontal"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content">

                    <ImageView
                        android:id="@+id/ivToolbarDataSource"
                        android:layout_gravity="center_vertical"
                        android:layout_marginRight="2dp"
                        android:layout_width="24dp"
                        android:layout_height="24dp" />

                    <TextView
                        android:id="@+id/tvToolbarTitle"
                        style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title"
                        android:theme="?actionBarThemeStyle"
                        android:layout_gravity="center_vertical"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content" />

                </LinearLayout>

                <TextView
                    android:id="@+id/tvToolbarSubTitle"
                    style="@style/TextAppearance.AppCompat.Widget.ActionBar.Subtitle"
                    android:theme="?actionBarThemeStyle"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content" />

            </LinearLayout>



        </android.support.v7.widget.Toolbar>

        <!-- BUG: http://stackoverflow.com/questions/30541409/coordinatorlayoutappbarlayout-does-not-draw-toolbar-properly -->
        <View
            android:layout_width="fill_parent"
            android:layout_height="1dp"/>

    </android.support.design.widget.AppBarLayout>

    <FrameLayout
        android:id="@+id/frame_container"
        android:fitsSystemWindows="true"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|right"
        android:layout_margin="32dp"
        android:src="@drawable/ic_local_offer_white_24dp"
        app:backgroundTint="?attr/colorPrimary"
        app:borderWidth="0dp"
        app:fabSize="normal"
        app:rippleColor="?attr/colorPrimaryDark"
        app:layout_anchorGravity="bottom|right|end"
        app:layout_behavior="com.test.classes.ScrollAwareFABBehavior"/>

</android.support.design.widget.CoordinatorLayout>

And here is my fragment, that will be placed in the main activity:

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:fitsSystemWindows="true"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v4.widget.SwipeRefreshLayout
        android:id="@+id/srlImages"
        android:fitsSystemWindows="true"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/rvImages"
            android:fitsSystemWindows="true"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </android.support.v4.widget.SwipeRefreshLayout>

    <TextView
        android:id="@+id/tvEmpty"
        android:gravity="center"
        android:layout_centerInParent="true"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</RelativeLayout>

EDIT - Screenshots

I use a light/dark base theme and theme everything by hand (because the user can select any color as primary/accent color), so don't mind that the toolbar is white (it's the default's theme background color and primary color). I added a black border as well so that you see where the activity ends...

• First Screenshot: Shows the toolbar, nothing is scrolled
• Second Screenshot: I just started scrolling => the toolbar now should scroll away
• Third Screenshot: the main content should now scroll underneath the nav bar...

In the end, I'll of course make the toolbar and navbar semi transparent for a better visual effect...

Answer 1

tl;dr Set android:fitsSystemWindows="false" at least to the root CoordinatorLayout and to the inner fragment container, @frame_container.

This might not be the final solution (i.e. there might be other fitsSystemWindows to change) so tell me if you have any problems.

why

When it comes to status bar, I think of fitsSystemWindows like so:

• fitsSystemWindows="false" : draws the view normally, under the status bar because of the window flags you have set.
• fitsSystemWindows="true" : draws the view normally, under the status bar because of the window flags you have set, but adds a top padding so that content is drawn below the status bar and they don't overlap.

In fact, in my opinion, the white you see is not the status bar color, but rather your CoordinatorLayout background. That is due to fitsSystemWindows="true" on the coordinator: it draws the background to the whole window, but adds top padding to the content so inner views are not covered by status bar.

This is not what you want. Your inner content must be covered by the status bar, and so you have to set fitsSystemWindows="false" to the coordinator (so it won't apply top padding) and probably to the content itself.

Once you get how it works, it is easy to debug and achieve the effect you are looking for. Actually, it is not. Years pass, but I still spend hours trying to figure out the right fitsSystemWindows combination, because most Views (in the support libraries at least) override the default behavior that I stated above, in ways that are mostly not intuitive. See this post for a small guide on how to use it.