How to change the text on the action bar

Update: Latest ActionBar (Title) pattern:

FYI, ActionBar was introduced in API Level 11. ActionBar is a window feature at the top of the Activity that may display the activity title, navigation modes, and other interactive items like search.

I exactly remember about customizing title bar and making it consistent through the application. So I can make a comparison with the earlier days and can list some of the advantages of using ActionBar:

1. It offers your users a familiar interface across applications that the system gracefully adapts for different screen configurations.
2. Developers don't need to write much code for displaying the Activity Title, icons and navigation modes because ActionBar is already ready with top level abstraction.

For example:

=> Normal way,

getActionBar().setTitle("Hello world App");   
getSupportActionBar().setTitle("Hello world App");  // provide compatibility to all the versions

=> Customizing Action Bar,

For example:

@Override
public void setActionBar(String heading) {
    // TODO Auto-generated method stub

    com.actionbarsherlock.app.ActionBar actionBar = getSupportActionBar();
    actionBar.setHomeButtonEnabled(true);
    actionBar.setDisplayHomeAsUpEnabled(false);
    actionBar.setDisplayShowHomeEnabled(false);
    actionBar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.title_bar_gray)));
    actionBar.setTitle(heading);
    actionBar.show();

}

Styling the Action Bar:

The ActionBar provides you with basic and familiar looks, navigation modes and other quick actions to perform. But that doesn't mean it looks the same in every app. You can customize it as per your UI and design requirements. You just have to define and write styles and themes.

Read more at: Styling the Action Bar

And if you want to generate styles for ActionBar then this Style Generator tool can help you out.

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Old: Earlier days:

=> Normal way,

you can Change the Title of each screen (i.e. Activity) by setting their Android:label

   <activity android:name=".Hello_World"
                  android:label="This is the Hello World Application">
   </activity>

=> Custom - Title - bar

---

But if you want to Customize title-bar in your own way, i.e. Want to put Image icon and custom-text, then the following code works for me:

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"/>

titlebar.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="400dp" 
  android:layout_height="fill_parent"
  android:orientation="horizontal">

<ImageView android:id="@+id/ImageView01" 
            android:layout_width="57dp" 
            android:layout_height="wrap_content"
            android:background="@drawable/icon1"/>

<TextView 

  android:id="@+id/myTitle" 
  android:text="This is my new title" 
  android:layout_width="fill_parent" 
  android:layout_height="fill_parent" 
  android:textColor="@color/titletextcolor"
   />
</LinearLayout>

TitleBar.java

public class TitleBar extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final boolean customTitleSupported = 
                requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
        setContentView(R.layout.main);
        if (customTitleSupported) {
            getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE,
                R.layout.titlebar);
        }
        final TextView myTitleText = (TextView) findViewById(R.id.myTitle);
        if (myTitleText != null) {
            myTitleText.setText("NEW TITLE");
            // user can also set color using "Color" and then
            // "Color value constant"
            // myTitleText.setBackgroundColor(Color.GREEN);
        }
    }
}

strings.xml

The strings.xml file is defined under the values folder.

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello World, Set_Text_TitleBar!</string>
    <string name="app_name">Set_Text_TitleBar</string>
    <color name="titlebackgroundcolor">#3232CD</color>
    <color name="titletextcolor">#FFFF00</color>
</resources>

You can define the label for each activity in your manifest file.

A normal definition of a activity looks like this:

<activity
     android:name=".ui.myactivity"
     android:label="@string/Title Text" />

Where title text should be replaced by the id of a string resource for this activity.

You can also set the title text from code if you want to set it dynamically.

setTitle(address.getCity());

with this line the title is set to the city of a specific adress in the oncreate method of my activity.