androidbackgroundandroid-actionbar-compatshapedrawable

Custom (gradient) background of ActionBar Compat


I am using Action Bar Compat so that my action bar with navigation drawer was backward compatible down to API level 9 and I want to change the background of the action bar.

I copied the code from Android Developers:

<?xml version="1.0" encoding="utf-8"?>
<resources>
<!-- the theme applied to the application or activity -->
<style name="CustomActionBarTheme"
       parent="@style/Theme.AppCompat.Light.DarkActionBar">
    <item name="android:actionBarStyle">@style/MyActionBar</item>

    <!-- Support library compatibility -->
    <item name="actionBarStyle">@style/MyActionBar</item>
</style>

<!-- ActionBar styles -->
<style name="MyActionBar"
       parent="@style/Widget.AppCompat.Light.ActionBar.Solid.Inverse">
    <item name="android:background">@drawable/actionbar_background</item>

    <!-- Support library compatibility -->
    <item name="background">@drawable/actionbar_background</item>
</style>
</resources>

And here comes the problem.

When I put an image drawable or a color as the background, it works fine. However I want to define the background as a gradient shape, so my actionbar_background looks like:

<?xml version="1.0" encoding="utf-8"?>
<shape
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="line">
<gradient
        android:startColor="@color/ac_bg_start"
        android:endColor="@color/ac_bg_end"
        android:type="linear"/>
<size
        android:width="1dp"
        android:height="48dp"/>
</shape>

I want it to be repeated in horizontal way but even this results in error, in fact, very interesting error. Test device and even the emulator gets restarted when I try to run the app. I was able to catch DeadObjectException before restarting.

How should the background drawable look like?


Solution

  • I am currently working on the same task.

    Here is my action_bar_bg.xml file in which I define the gradient for my action bar.

    <?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android">
        <gradient
            android:angle="90"
            android:centerColor="@color/turquoise_action_bar"
            android:endColor="@color/dark_turquoise"
            android:startColor="@color/dark_turquoise" />
    </shape>
    

    DeadObjectException

    android:shape="line" can't be used if there is a gradient inside. I tested it; my Samsung Galaxy Note 10.1 N8000 restarted, and there was a DeadObjectException.

    The linear type of gradient pattern is the default value. So you don't have to declare it explicitly.

    Here is my styles.xml in the values folder.

    <resources>
    
        <!-- Base application theme. -->
        <style name="AppThemeBase" parent="Theme.AppCompat.Light.DarkActionBar">
            <item name="android:actionBarStyle">@style/PeopleCanAct</item>
            <!-- Support library compatibility -->
            <item name="actionBarStyle">@style/MyActionBar</item>
        </style>
    
        <style name="AppTheme" parent="AppThemeBase">
            <!-- All the customizations that are NOT specific to a particular API level can go here -->
        </style>
    
        <!-- ActionBar styles -->
        <style name="MyActionBar" parent="@style/Widget.AppCompat.Light.ActionBar.Solid.Inverse">
            <item name="android:background">@drawable/action_bar_bg</item>
            <!-- Support library compatibility -->
            <item name="background">@drawable/action_bar_bg</item>
        </style>
    
    </resources>
    

    Gradient Drawable