At first glance it seems pretty easy to add a background drawable to your Android material design Toolbar. However, if your app bar consists of several views (e.g. an additional TabLayout) or if you want a transparent status bar, it gets complicated.
The final result
In this tutorial I will show you how to overcome several difficulties in order to implement a layout similar to the following:
We start with a new Tabbed Activity with Action Bar Tabs (with ViewPager). Android Studio generates a layout file and the activity which are the perfect start for this project. We just need to make a few optimizations here and there so that it looks like the end result above. The first step is to get rid of the floating action button in your activity_main.xml and in the MainActivity.java code and after that your app should look like this:
With this being your layout file:
Making the status bar transparent
First of all, you need to change your activity theme to have a transparent status bar. Therefore add a theme to your styles.xml:
And set this theme as your activity theme in the AndroidManifest.xml:
This makes almost no difference to the appearance of your app, only the status bar looks a bit darker. However, this is necessary for your background image to be visible below the status bar.
Adding a background image to the AppBarLayout
After that, you need to add your background drawable resource to your layout by adding the following attribute to your AppBarLayout in your activity_main.xml layout file: android:background = "@drawable/ic_header". You can download the background drawable I am using here as vector graphic which was created in Adobe Illustrator. Unfortunately, the result looks not as good as expected (your layout can differ based on the size of the background image you chose):
There are several issues with your layout:
- The Toolbar is not transparent so there is a lot of blue (primary color)
- The image is not visible under our status bar, even though we made it transparent before
- You can scroll the Toolbar away
- The app bar layout changed its size based on the background image
To fix the first issue we simply need to remove the android:background = "?attr/colorPrimary" attribute from our Toolbar to make it transparent instead of filled with the primary color.
Furthermore, to fix the second issue we need to add some android:fitsSystemWindows = "true" attributes to our layout since this attribute is not inherited. So add it to your AppBarLayout and to your Toolbar in order to make the AppBarLayout use the space below the status bar and to position your Toolbar just below the status bar. Additionally, remove the android:paddingTop = "@dimen/appbar_padding_top" attribute from your AppBarLayout.
Moreover, to change the third issue remove the app:layout_scrollFlags = "scroll|enterAlways" attribute from your Toolbar.
Last but not least, the Toolbar is way to big because the background drawable is part of the content of the view and the attribute android:layout_height = "wrap_content" is set for your AppBarLayout. Nevertheless, you can't just change the height of the app bar layout to a fixed value, since the status bar height differs from phone to phone. Luckily, I can tell you the height of a TabLayout which is 48dp high and the height of a Toolbar which is 56dp high. Consequently, our AppBarLayout needs to have the height 48dp+56dp+StatusBarHeight. You need to set this height programmatically in the onCreate method of your MainActivity.java by using the following code:
Just call the method setAppBarHeight in your onCreate method and that's it!
Finally, your app should now look like this:
With this being the final activity_main.xml layout file:
Keep in touch
Thank you for reading! Feel free to comment if you have any questions, ideas or just want to talk to me and remember to check out my other posts.
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