Using android's action bar

22/05/2015 Using Android's Action Bar
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Using Android's Action Bar
Written by Clive
Where's the action?
The Action Bar
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The Action Bar
The Action Bar is at the top of every activity screen
The app icon displays in it by default.
You can replace the app icon with your company logo if you wish.
You can also include tabs, drop-down lists, pop-ups and menus in the Action Bar.
I’ll show you how to include menu items as Action items in the Action Bar.
Use the Action Bar on all devices, well almost…
The Action Bar has been available since Android 3.0 (Honeycomb, API level 11).
The Support Library
Using the support library makes the Action Bar available since Android 2.1 (API level 7).
We’ll be using the support library in our tutorial.

Adding an Action Bar
Import the ActionBar class
Make sure that you import the correct ActionBar class:
We’re using the support library class because we’re targeting earlier devices
Which class you import depends on the devices that you target:
API level 11 and above – import ActionBar
API level 10 and below – import support.v7.app.ActionBar. This is the one we’ll import
Create the activity
Create the activity by extending the ActionBarActivity class.
Include a theme
Edit the AndroidManifest.xml file to include the Theme.AppCompat.Light theme
Hiding the Action Bar
You can hide the Action Bar:

Use getSupportActionBar() to get an instance of the Action Bar then call hide() to hide it
Showing the Action Bar
You can show the Action Bar by getting an instance of the Action Bar and then call show():
Showing the Action Bar
Brand your app. Use your logo
The image on the left can either be the app icon or your company logo
Which image is displayed depends on these settings in the manifest:
The icon attribute image is the default
Include the logo attribute and this image will replace the icon image.
But there’s a catch…
The logo image will not show on any device running Android 10 and lower. Unless…

You include this code in your activity:
Get an instance of the action bar by calling getSupportActionBar(). Then call setLogo() to set the logo
If you use this workaround then you don’t have to include the logo attribute in the manifest.
Action items
Action items are menu options.
You can display the most important action items in the Action Bar.
Action items that are not important or cannot fit in the Action Bar end up in the action overflow.
You can access the action overflow by pressing the action overflow button

Pressing the overflow button reveals the Settings item. The Help and Phone items are displayed as Action Buttons in
the Action Bar
Creating the action items
Create the action items in a menu file and save it in the res>menu folder.
Here’s a code snippet:
Note the following:
icon – this image will show in the Action Bar. It will not show in the overflow
title – the title will show in the overflow. It will show in the Action Bar, if:
you include withText in the showAsOption attribute
there is room
app:showAsAction – because we are using the support library, we must use the custom namespace (app)
defined in the <menu> tag of the menu xml file:
The namespace is defined in the menu tag

showAsAction – use this to declare whether or not you want the action item to appear in the Action Bar. Some
common options are:
ifRoom – shows the action item in the Action Bar if there is room
withText – includes the action item’s title if there is room
never – never show this action item in the Action Bar
Always include an action title
You should always include an action title because:
only a title appears in the action overflow
blind users need it for their screen readers
long-pressing the Action Button displays a tooltip
Long-pressing the Action Button displays the tooltip, Phone
Getting action icons
You can download free action icons from the official Android site
(http://developer.android.com/design/downloads/index.html)
Displaying the Action Bar in an activity
The activity’s onCreateOptionsMenu() inflates the menu file and places the action items in the Action Bar.
Here’s the code:

This inflates the menu resource file and loads the action items into the Action Bar
Note the following:
getMenuInflater().inflate() – inflates the menu found in the resource file into the menu object
Handling clicks
Pressing an action item, calls onOptionsItemSelected(), passing the selected item as a parameter.
Here’s the code:
Note the following:

getItemId() – gets the ID of the selected action item
switch() – we use a switch statement to match the selected item ID with the id’s of our menu items as saved in
the menu resource file. The appropriate code is executed if it matches
message – we create a message for each of the action item id’s. The matching id’s message will display as a
Toast (/articles/making-toast.html)
Pressing an Action Button
Action item icons in the Action Bar are known as Action Buttons.
Pressing the Phone Action Button uses an intent to start another activity.
The second activity
This activity demonstrates the Split Action Bar and Up Navigation.
Splitting the Action Bar
You can split the Action Bar when running on narrow screens.
The action items will display at the bottom of the screen. This leaves room for navigation and title elements at the
top.

A narrow screen with a split Action Bar. The separate bar at the bottom of the screen displays the action items

The bar is not split on wide screens
Splitting the Bar: It depends on the device
Accommodating API 14 and higher
For devices using API level 14 or higher, add the uiOptions attribute to specific activities or the application as a
whole.
Accommodating API 13 and below
For devices using API level 13 or lower, add the <meta-data> element to the activities where you want to split the
action bar:

Include the first <meta-data> element to split the Action Bar on older devices
Navigating up with the app icon
Up navigation takes the user to the parent of the current activity.
The Back button takes the user to the previous activity.

If pressing an action button in activity A starts activity C then pressing the Up Navigation icon in activity C will return
the user to activity A. If the user reached activity C from A via B then, pressing the Back button will first return to
activity B and then to activity A

Enable the app icon as an Up button
The caret to the left of the logo icon indicates an Up Button
Here’s the code:
Use getSupportActionBar() to get an instance of an Action Bar then call setDisplayHomeAsUpEnabled(true) to enable
the Up Button
For it to work you need to specify the parent activity in the manifest file:
Add this code to the activity where you have enabled the Up Button
Run the app
The first activity
The first activity will display the Action Bar with the Strawberry logo on the left and the Action Buttons on the right.

Android apps and Google Drive: Picking files
(/index.php/articles/android-apps-and-google-drive-
picking-files.html)
Related items
Change the device orientation. The Phone action item’s title is displayed in landscape mode but not in portrait
mode.
Pressing the Phone action button starts the second activity.
The second activity
The Action Bar is split if the screen is narrow.
Change the device orientation. The Action Bar is not split when the device is in landscape mode.
The app logo is also an Up Button. Pressing the logo returns the user to the first activity.
I hope that you have found this tutorial useful.
You may also be interested in Android Fragments, Action Bar, Menus, Notifications and Tabs.
(http://www.amazon.com/Android-Fragments-Action-Menus-Notifications-ebook/dp/B00B7NQ2KQ/ref=sr_1_4?
ie=UTF8&qid=1393233618&sr=8-4&keywords=clive+sargeant)
This tutorial was created using Android Studio (http://www.amazon.com/Android-Studio-How-guide-tutorial-
ebook/dp/B00HZ1O78S/ref=sr_1_3?ie=UTF8&qid=1393233618&sr=8-3&keywords=clive+sargeant). You can
download the project files here (/downloads.html)
Are you using Eclipse or another IDE? Here's how you can use this project's Android Studio files (/articles/importing-
android-studio-projects-into-eclipse.html).

Android apps and Google Drive: A tutorial
(/index.php/articles/android-apps-and-google-drive-a-
tutorial.html)
Converting Android Activities to Fragments
(/index.php/articles/converting-android-activities-to-
fragments.html)
Let your apps take a giant leap. A Tutorial
(/index.php/ebooks/let-your-apps-take-a-giant-leap-a-
tutorial.html)
Android: Launching activities
(/index.php/articles/android-launching-activities.html)

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