Setting Up the Action Bar PREVIOUS NEXT
In its most basic form, the action
bar displays the title for the activity
and the app icon on the left. Even
in this simple form, the action bar is
useful for all activities to inform
users about where they are and to
maintain a consistent identity for
your app.
Figure 1. An action bar with the app
icon and activity title.
Setting up a basic action bar
requires that your app use an
activity theme that enables the
action bar. How to request such a
theme depends on which version of
Android is the lowest supported by
your app. So this lesson is divided
into two sections depending on
which Android version is your lowest
supported.
Support Android 3.0 and Above
Only
Beginning with Android 3.0 (API
level 11), the action bar is included
in all activities that use the
Theme.Holo theme (or one of its
descendants), which is the default
theme when either the
targetSdkVersion or
minSdkVersion attribute is set to
"11" or greater.
So to add the action bar to your
activities, simply set either attribute
to 11 or higher. For example:
<manifest ... >
<uses-sdk android:minSdkVersion ="11" ... />
...
</manifest>
Note: If you've created a custom
theme, be sure it uses one of the
Theme.Holo themes as its parent.
For details, see Styling the Action
Bar .
Now the Theme.Holo theme is
applied to your app and all activities
show the action bar. That's it.
Support Android 2.1 and Above
Adding the action bar when running
on versions older than Android 3.0
(down to Android 2.1) requires that
you include the Android Support
Library in your application.
To get started, read the Support
Library Setup document and set up
the v7 appcompat library (once
you've downloaded the library
package, follow the instructions for
Adding libraries with resources).
Once you have the Support Library
integrated with your app project:
1. Update your activity so that it
extends ActionBarActivity. For
example:
public class MainActivity extends ActionBarActivity { ... }
2. In your manifest file, update either
the <application> element or
individual <activity> elements to
use one of the Theme.AppCompat
themes. For example:
<activity android:theme = "@style/Theme.AppCompat.Light" ... >
Note: If you've created a custom
theme, be sure it uses one of the
Theme.AppCompat themes as its
parent. For details, see Styling the
Action Bar .
Now your activity includes the action
bar when running on Android 2.1
(API level 7) or higher.
Remember to properly set your app's
API level support in the manifest:
<manifest ... >
<uses-sdk android:minSdkVersion ="7" android:targetSdkVersion = "18" />
...
</manifest>