PART1：Make Android2.1 Support ActionBar
Last evening I learnt how to make android2.1 support actionbar from Android Developers.The page is HERE,Click.
To sum up , I briefy illustrate the main steps:
1.Add the v7 appcompat library , which is not just a jar file but a library with resources.
2.Let the Activities that originally extending "Activity" to extend "ActionBarActivity".
3.In your manifest file, update either the <application> element
or individual <activity> elements
to use one of the Theme.AppCompat themes.
For example:
That‘s it.
BTW,if you wanna know what the Theme.AppCompat themes contain, "Alt + /" is not capable , you can find them also on Android Developers,
Thme.AppCompat.For example, you find
public static int Theme_AppCompat_Light_DarkActionBar,
then you should change the theme like this:
android:theme="@style/Theme.AppCompat.Light.DarkActionBar"
keep in mind that the first letter in each word should be its upper class form.
PART2:Adding Action Buttons
Android Developers says the most important buttons should be set on the ActionBar, buttons that are not so important should be placed in the Overflow Button.
------Met a Problem----
After adding a key-value pair in strings.xml file, MainActivity.java pointed out that R.java can‘t be found.So open "gen" folder,sure enough R.java is missing.Checking the xml file,I found in <string name="action_search">Search!!</string>, the "s" in the string was written as a upper class form.change it back to lower, R.java returned.Problem solved.
------------------------