Develop Reference

Android custom theme

Hello I'm making a custom theme for my app. I want to have a custom ActionBar and background for the rest of the app (below the ActionBar). I'm wondering how to do the background. Right now I have:
<style name="MyTheme" parent="android:Theme.Holo">
<item name="android:actionBarStyle">#style/dActionBar</item>
</style>
<style name="dActionBar" parent="#android:style/Widget.Holo.ActionBar">
<item name="android:background">#4C721D</item>
<item name="android:textColor">#FFFFFF</item>
</style>
Would I just have to do <item name-"android:background"></item> in MyTheme or would I have to create another style? After I create this do I need to put it in the res/styles folder? Also what are the API restrictions on this, if any?

Don't forget to apply your theme to your application in your AndroidManifest.xml.
<application android:theme="#style/CustomActivityTheme" ... />
You can find all the information about styling the Actionbar here.
To style your ActionBar with a nice Holo-look, try this website
Hope this helps!

Try to use below code in your Style.xml file
<resources>
<style name="Theme.Sample" parent="Theme.AppCompat">
<item name="android:colorBackground">#color/primary_material_dark</item>
<item name="actionBarTheme">#color/colorGray</item>
</style>
</resources>
Just need to use android:colorBackground as a name of item to define the background color like as below:
<item name="android:colorBackground">#color/primary_material_dark</item>
Hope you get your answer,Thanks.

text appearance doesn't work inside my theme

I'm trying to put a style in all my app, so i created a theme with my style inside :
<resources>
<style name="MyTheme" parent="android:Theme.Holo.Light">
<item name="android:textAppearance">#style/subtitle</item>
</style>
<style name="subtitle parent="#android:style/TextAppearance">
<item name="android:textColor">#color/purple</item>
<item name="android:textSize">40sp</item>
</style>
</resources>
But textAppearance doesn't work it stay the same, but when i put something like textColor in my theme, it works

This is a quite old question, but the answer may help someone.
The key to solve this is in the "precedence order of styling techniques" here: 
on the top is the highest precedence, at the bottom is the lowest precedence.
As we can see theme has the lowest precedence, in your example, your android:textAppearance property is being overridden by the default style of every view that accepts this attribute, the default style property is defined in every them for every specific view that accepts this attribute, in this case android:Theme.Holo.Light provides the default style for textView as android:textViewStyle... for buttons is android:buttonStyle (which inherits its textAppearance from TextView), and so on.
So if you are trying to apply that android:textAppearance property to a TextVew you should use <item name="android:textViewStyle">#style/subtitle</item> instead of <item name="android:textAppearance">#style/subtitle</item> inside MyTheme. Away to veryfy this is setting android:textViewStyle to null, that way your current code will work fine with textViews <item name="android:textViewStyle">null</item>
This post explains this precedence a bit deeper:
https://medium.com/androiddevelopers/whats-your-text-s-appearance-f3a1729192d

What I can see is, you have not declared the color in your xml for theme. Please add the following line within the <resources> and try. Your xml will look like:
<resources>
<style name="MyTheme" parent="android:Theme.Holo.Light">
<item name="android:textAppearance">#style/subtitle</item>
</style>
<color name="purple">code for your color</color>
<style name="subtitle parent="#android:style/TextAppearance">
<item name="android:textColor">#color/purple</item>
<item name="android:textSize">40sp</item>
</style>
I think this will do.

Depends on your target API you need to put your customization code in different /res/values-vxx/style.xml files.

For TextView, try android:textAppearanceSmall inside your theme instead.

How to apply themes for an exact view?

For example when I define a style tag in XML, all views of all types get that theme. Is there any solution to difference between styles for view types? here is some code:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="buttonTheme" parent="android:Theme.Holo">
<item name="android:drawableLeft">#drawable/ic_launcher</item>
</style>
<style name="textTheme" parent="android:Theme.Holo">
<item name="android:textColor">#ff0000</item>
</style>
</resources>

I think there's a small confusion in terms between a style and a theme. You are talking about defining custom styles for a widget in your application. A Theme is a collection of these styles applied globally to an Activity or Application. The custom styles you have created for a button and text view can be applied to a new custom theme so all buttons and text items share the same attributes.
I think what you are looking for is something more like this.
<style name="ApplicationTheme" parent="android:Theme.Holo">
<item name="buttonStyle">#style/MyButtonStyle</item>
<item name="textAppearance">#style/MyTextAppearance</item>
</style>
<style name="MyButtonStyle" parent="android:Widget.Button">
<item name="android:drawableLeft">#drawable/ic_launcher</item>
</style>
<style name="MyTextAppearance" parent="android:TextAppearance">
<item name="android:textColor">#ff0000</item>
</style>
Here, we have created two new styles (one for the button appearance and one for default text appearance), and then applied those as attributes in a new custom theme. You can now apply this theme in your manifest or in View constructors by referencing #style/ApplicationTheme or R.style.ApplicationTheme

You can do this by adding the attribute android:theme="" to the specific activity in your AndroidManifest.xml file
Example:
<activity android:theme="#style/CustomTheme">

Want to overload Button style

I want to overload how an android Button looks, except I want to overload only one attribute i.e. the android:background. I know I could write something like:
<style name="App_TextButtonStyle" parent="???">
<item name="android:background">#drawable/filled_roundededges_nostroke</item>
</style>
Where parent="???" specifies which style I inherit from. My question is which style should I inherit from do that I get everything from the android default style for buttons and just define a new background.

I have used style for buttons without specifying "parent" attribute
<style name="BigButtonStyle">
<item name="android:layout_width">wrap_content</item>
<item name="android:layout_height">wrap_content</item>
<item name="android:layout_gravity">center_horizontal</item>
<item name="android:background">#drawable/backbutton</item>
<item name="android:textColor">#FFFFFF</item>
<item name="android:textSize">8pt</item>
<item name="android:textStyle">bold</item>
<item name="android:layout_margin">10pt</item>
</style>
I think it could be enough for you to define your style without "parent".

This is mostly for future visitors, I found a solution to the problem:
<style name="App_TextButtonStyle" parent="#android:style/Widget.Button">
<item name="android:background">#drawable/filled_roundededges_nostroke</item>
</style>
#android:style/Widget.Button references the default style of the button in the currently selected theme. You could also use the holo widget button style #android:style/Widget.Holo.Button (available since api 11).
You might want to look in <android-sdk-install-folder>/platforms/android-XX/data/res/values for the files styles.xml and themes.xml to check out all styles android uses for a given platform version.

textColor not applied when used as them

I have a style that includes textColor, textSize, textStyle and typeface. When applied directly to an EditText widget, the color of the text is as specified (as well as the other attributes), but when applied as a theme to the activity or the entire application, the size is fine but the color is not applied. What I am missing?
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="fap" parent="android:Theme.Holo">
<item name="android:textSize">24sp</item>
<item name="android:textColor">#FF0000</item>
<item name="android:textStyle">normal</item>
<item name="android:typeface">normal</item>
</style>
</resources>

This is quite simple : you are not overriding android default style, your just creating a new one which extends android:Widget.EditText. Thus, the style is not applied.
To correct this, into your theme definition, just add :
<item name="android:editTextStyle">#style/fap</item>
Now, each time Android instanciate an EditText, when it load default style values, it will find your fap style.
Edit:
searching through android's source code is very usefull. Check https://android.googlesource.com/platform/frameworks/base/+/master/core/res/res/values/attrs.xml
https://android.googlesource.com/platform/frameworks/base/+/master/core/res/res/values/themes.xml
https://android.googlesource.com/platform/frameworks/base/+/master/core/res/res/values/styles.xml
https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/widget/EditText.java
for example.

EditText widget just can't get these parameters from an activity theme. It gets its default style from the android:editTextStyle parameter of the activity theme. So you have to create your own style:
<style name="MyEditText" parent="android:Widget.EditText">
<item name="android:textSize">24sp</item>
<item name="android:textColor">#FF0000</item>
<item name="android:textStyle">normal</item>
<item name="android:typeface">normal</item>
</style>
And then set it as EditText style in the activity theme:
<style name="fap" parent="android:Theme.Holo">
<item name="android:editTextStyle">#style/MyEditText</item>
</style>
Hope this will work because I haven't tried this code.