Learning Android ActionBar

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.

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Learning Android ActionBar,,5-wow.com