Develop Reference

Android styles, difference between api levels

I'm trying to learn how to Style my application using the styles.xml file and I need some clarification on a few things to understand it.
In an Item, what is the difference between setting android:actionbarstyle and just actionbarstyle ? I know that in this particular case, I have to define both, but why? And what about all other cases, for example android:colorPrimary and just colorPrimary? In that case I get an error saying that android:colorPrimary can only be used with min API level 21. So does someone have a good explanation on what the android: prefix does and how it affects my app?
Is there a reference to the different parent styles, such as parent="#style/Widget.AppCompat.Light.ActionBar and what they mean? How do I find a list of the different parent styles available for a specific item and what I can "override" in them? Right now, it's mostly guessing on my part....
Just as a reference, I'm posting my current styles.xml file.
<resources xmlns:android="http://schemas.android.com/apk/res/android">
<style name="AppTheme" parent="MyTheme"/>
<style name="MyTheme" parent="Theme.AppCompat.Light">
<item name="actionBarTheme">#style/MyTheme.ActionBarTheme</item>
<item name="android:actionBarStyle">#style/MyTheme.ActionBarStyle</item>
<item name="actionBarStyle">#style/MyTheme.ActionBarStyle</item>
<item name="colorPrimary">#color/my_green</item>
<item name="colorPrimaryDark">#color/my_forest</item>
<item name="colorAccent">#color/my_soil</item>
<item name="drawerArrowStyle">#style/MyTheme.DrawerArrowStyle</item>
<item name="android:actionOverflowButtonStyle">#style/MyTheme.OverFlow</item>
<item name="android:actionMenuTextColor">#color/white</item>
<item name="homeAsUpIndicator">#drawable/abc_ic_ab_back_mtrl_am_alpha</item>
<item name="android:homeAsUpIndicator">#drawable/abc_ic_ab_back_mtrl_am_alpha</item>
<item name="colorControlNormal">#color/my_green</item>
<item name="colorControlActivated">#color/my_forest</item>
<item name="colorControlHighlight">#color/my_deep_green</item>
</style>
<style name="MyTheme.ActionBarTheme" parent="#style/ThemeOverlay.AppCompat.ActionBar">
<!-- This sets the BACK arrow to white. Otherwise it's black. Must be placed in the theme-->
<item name="colorControlNormal">#color/white</item>
</style>
<style name="MyTheme.ActionBarStyle" parent="#style/Widget.AppCompat.Light.ActionBar">
<item name="android:background">#color/my_green</item>
<item name="background">#color/my_green</item>
<item name="android:titleTextStyle">#style/MyTheme.ActionBar.TitleTextStyle</item>
<item name="titleTextStyle">#style/MyTheme.ActionBar.TitleTextStyle</item>
<item name="colorControlNormal">#color/white</item>
</style>
<style name="MyTheme.ActionBar.TitleTextStyle" parent="#android:style/TextAppearance.Holo.Widget.ActionBar.Title">
<item name="android:textColor">#color/white</item>
</style>
<style name="MyTheme.DrawerArrowStyle" parent="Widget.AppCompat.DrawerArrowToggle">
<item name="spinBars">true</item>
<item name="color">#color/white</item>
</style>
<style name="MyTheme.OverFlow" parent="Widget.AppCompat.ActionButton.Overflow">
<item name="android:tint">#color/white</item>
</style>
</resources>

I will try my best to explain and will concentrate on:
<item name="colorPrimary">#color/my_green</item>
<item name="colorPrimaryDark">#color/my_forest</item>
<item name="colorAccent">#color/my_soil</item>
These attributes are regularly available with API level 21. In general you use attributes with the "android" prefix.
If you define all your styles in the styles.xml of your values folder and if you are using app compat, then you need both.
Without the prefix the attributes applies for pre L devices. i.e. App Compat. To get it work for L devices and higher you need to specifiy the attribute again with the "android" prefix.
And to get the other Android styles you can step into them, like you step into classes and the implementations. For Mac I press the command button and then click with the mouse on the specific style.

How to inherit from a style specified from a different api version

This is a pretty basic question - I am supporting API versions 11+ and I want to use functionality on phones that have a newer API version. However, it would be nice if I didn't have to re-define my style. So, for example, if, in values/styles.xml I have:
<resources
xmlns:android="http://schemas.android.com/apk/res/android">
<style name="Theme.MyApp.Input.Text">
<item name="android:layout_width">match_parent<item>
<item name="android:layout_height>wrap_content</item>
</style>
</resources>
and then in values-v14/styles.xml I have:
<resources
xmlns:android="http://schemas.android.com/apk/res/android">
<style name="Theme.MyApp.Input.Text">
<item name="android:textAllCaps">true</item>
</style>
</resources>
Then, on devices that have API 14+, I'll get the union of the two styles.

The question is quite old but it is possible:
The following snippet is from values/styles.xml
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<item name="colorPrimary">#color/green</item>
<item name="colorPrimaryDark">#color/dark</item>
<item name="colorAccent">#color/green</item>
<item name="checkboxStyle">#style/AppTheme.CheckBox</item>
</style>
If you want to inherit (for eg) the same style and specialize in the API >=23 you must define a values/style-23.xml as below:
<style name="AppTheme.AppTheme23" >
<item name="android:windowLightStatusBar">true</item>
</style>
Obviously in the AndroidManifest.xml the theme to specify is:
android:theme="#style/AppTheme"
That's all folks!

Android Studio Material Design....styles.xml

I want to use the AppTheme android:Theme.Material.Light.DarkActionBar for my app. This is available from SDK 21...My minimum SDK is 16. I have the support library com.android.support:appcompat-v7:22.0.0 in my build gradle file. I want to create a second styles file under the the values folder. I want to have two styles files...one for Lollipop...greyed out version 22 next to it...and one for pre Lollipop. How to do this?

As said create a values folder for a specific Api Level
res/values-v21/styles.xml
res/values/styles.xml
In values/styles.xml create to styles:
<style name="AppTheme.Base" parent="Theme.AppCompat.Light.NoActionBar">
<item name="colorPrimary">#color/primaryColor</item>
<item name="colorPrimaryDark">#color/primaryColorDark</item>
<item name="colorAccent">#color/accentColor</item>
<item name="android:windowNoTitle">true</item>
<item name="windowActionBar">false</item>
</style
<style name="AppTheme" parent="AppTheme.Base">
</style>
In values-v21/styles.xml create to styles:
<!-- Themes for Android API21 -->
<style name="AppTheme" parent="AppTheme.Base">
<item name="android:colorPrimary">#color/primaryColor</item>
<item name="android:colorPrimaryDark">#color/primaryColorDark</item>
<item name="android:colorAccent">#color/accentColor</item>
</style>
Inside your AndroidManifest.xml you should use AppTheme as your global application theme
Further you should use the Toolbar from the SupportLibary instead of the default Actionbar. This is why the Base Theme sets the Actionbar to false

As suggested in the other answers you can use different styles.xml file in different folders.
I would like to add an option to other answers.
You can define a Base Style used by each versions, and customize singles attributes.
In res/values/styles.xml
<style name="AppTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar">
<item name="colorPrimary">#color/primaryColor</item>
<item name="colorPrimaryDark">#color/primaryColorDark</item>
<item name="colorAccent">#color/accentColor</item>
</style>
<style name="AppTheme" parent="AppTheme.Base">
<!-- custom pre-Lollipop attributes -->
</style>
In res/values-v21/styles.xml
<style name="AppTheme" parent="AppTheme.Base">
<!-- custom Lollipop attributes -->
</style>
Finally use the AppTheme in your Activity (you have to use a ` ActionBarActivity).

You should add another folder called "values-v21" in your "res" directory. Then create a "styles.xml" within that directory for your Lollipop styles.

Create two styles.xml files in different folders, e.g:
res/values-v21/styles.xml
res/values/styles.xml

Alternative Layouts

I am developing an android application that I want to support Material Design for devices running 5.0+ and devices from 4.1 to 4.4.
I am using the appcompat library to get some support for older versions.
Now I am faced with attributes that are only present in v21, like elevation.
I can create a layout-v21 folder and add my activity's layout there, again, which leads to quite a bit of duplication.
Do you do this another way?
Is there a way to use styles for this? How do I subclass a style from values to values-v21

Here is a link that I have used that gives some information about overriding styles/themes for v21 Lollipop: http://antonioleiva.com/material-design-everywhere/
Essentially you can do in values/themes.xml
<style name="AppTheme" parent="AppTheme.Base"/>
<style name="AppTheme.Base" parent="Theme.AppCompat">
<item name="colorPrimary">#color/colorPrimary</item>
<item name="colorPrimaryDark">#color/colorPrimary</item>
<item name="android:windowNoTitle">true</item>
<item name="windowActionBar">false</item>
</style>
And then in values-v21/themes.xml
<style name="AppTheme" parent="AppTheme.Base">
<item name="android:windowContentTransitions">true</item>
<item name="android:windowAllowEnterTransitionOverlap">true</item>
<item name="android:windowAllowReturnTransitionOverlap">true</item>
<item name="android:windowSharedElementEnterTransition">#android:transition/move</item>
<item name="android:windowSharedElementExitTransition">#android:transition/move</item>
</style>
To override AppTheme for v21 but to retain all the properties for the AppTheme.Base from pre-v21.

Applying a theme to v7 Support Action Bar

I am using the support v7 library to implement ActionBar in my app..I have this in my styles.xml file
<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">
<style name="AppTheme" parent="#style/Theme.AppCompat.Light.DarkActionBar">
<item name="android:actionBarStyle">#style/ActionBarTheme</item>
</style>
<style name="ActionBarTheme" parent="android:Widget.ActionBar">
<item name="android:background">#FFFF0000</item>
</style>
</resources>
However, Eclipse complains in the actionBarStyle line. The error is this one:
android:actionBarStyle requires API level 11 (current min is 8)
What can I do to apply my theme to API levels 8-10?

You need to provide two API specific styles.xml. In your values/styles.xml use
<style name="AppTheme" parent="#style/Theme.AppCompat.Light.DarkActionBar">
<item name="actionBarStyle">#style/ActionBarTheme</item>
</style>
and in your values-v14/styles.xml use
<style name="AppTheme" parent="#style/Theme.AppCompat.Light.DarkActionBar">
<item name="android:actionBarStyle">#style/ActionBarTheme</item>
</style>

If you use latest v7 support library (v21 at the time of this post), there is no need to add android: prefix to any action bar attributes anymore.
In your case, adding the following to values/styles.xml will be sufficient:
<style name="AppTheme" parent="#style/Theme.AppCompat.Light.DarkActionBar">
<item name="actionBarStyle">#style/ActionBarTheme</item>
</style>
Reference: https://chris.banes.me/2014/10/17/appcompat-v21/#migration-from-previous-setup