Android Themes

Introduction

Android allows you to set the appearance of your application using themes. A theme specifies default colors, fonts, and images, for an Android activity or an entire application. Your application can use the device's built-in themes, or include custom themes. By default, Titanium applications use a custom theme called Titanium for their main activity. This theme defines the splash screen when the application starts, but otherwise defers to a device default theme. This theme is based on the AppCompat theme with a translucent background.

To update the look of your application, you can either:

• Use a different built-in Android theme
• Use a Titanium-defined theme
• Create a custom theme and define the elements you want to change
• Use the Android Material Theme to quickly customize the theme's color palette
• Use third-party tools to help you generate a custom theme

You can specify a unique theme per window or per activity.

Android themes

Android provides some built-in themes to easily change the overall appearance of your application. To use a built-in theme, you need to create a theme XML file for your project, specify the built-in theme you want to use, and reference it in the Android manifest section of your tiapp.xml file.

First, create a theme XML file in ./platform/android/res/values. Do NOT name the file theme.xml. Titanium uses this name as its default theme file, which is required to build the application. If you create a file called theme.xml, it will overwrite the default Titanium one and break the build process.

In the theme XML file, add the theme you want to use. Themes defined by the Android system, excluding the AppCompat ones, are prefaced with @android:style (for example, @android:style/Theme.Translucent). Custom themes defined by the application are prefaced with @style (for example, @style/Theme.MyTheme). For example, the file below adds support for some of the common built-in Android themes.

The Titanium SDK uses the appcompat library to provide support for themes. A benefit of using the appcompat library is that it provides ActionBar support on devices running Android 2.1.x and later. Prior to the usage of the appcompat library, the ActionBar was only available to devices running Android 3.x and later. Note that applications can only use the AppCompat themes.

Finally, to use a theme in your application, modify the Android section of your tiapp.xml file to reference the style name you want to use:

The screenshots below show the difference between the various built-in themes:

Titanium themes

The Titanium SDK includes a few predefined themes. You can use these themes in your application rather than creating your own.

NOTE: Do not create a theme with the same name as a predefined theme.

To apply a theme globally, in the tiapp.xml file, set the android:theme attribute to the theme name in the application element of the Android manifest section.

To change the theme on a per-window basis, set the theme name to the Window's theme property (available since Release 3.4.0).
NOTE: This method sets the theme for a window dynamically. In native Android doing so with a theme that has not been set for a particular Activity in the Manifest and a translucent background results in unstable behavior on different devices or OS versions. For instance the window may be solid black color and not showing any content. It is discouraged to use such themes dynamically.

Custom themes

To define custom themes, place the theme XML files with your custom styles in the platform/android/res/values folder. Do NOT name the file theme.xml. Titanium uses this name as its default theme file, which is required to build the application. If you create a file called theme.xml, it will overwrite the default Titanium one and break the build process.

Note that you can also define version-specific themes by adding a values-v<version> folder. For example a theme defined in values-v11 will be used for API level 11 (3.0/Honeycomb) and above, and a theme defined in values-v14 will be used for API level 14 (4.0/Ice Cream Sandwich) and above.

For example, if you want your theme to be based on the Light theme, create the following theme file:

The theme file above contains two custom style items:

1. The first item defines the "Theme.MyTheme" based on the Android Light theme. The style sets the window background using the image located at platform/android/res/drawable/example.png.
2. The second item overrides the default text color used in the theme. For convenience all colors can be defined in a separate file located at platform/android/res/values/colors.xml.
3. The third item overrides the Light theme's default cursor color for text fields and uses the TextField's color property as the cursor color.
4. The last item overrides the whole style used for buttons. The custom style is defined in the theme's file as a child of Widget.AppCompat.Button. In the custom style every property of it can be overriden. In this example the minimum width and height for every button are set to custom values. For convenience dimensions can be defined in a separate file located at platform/android/res/values/dimens.xml

To use the "Theme.MyTheme" theme in your application, modify the Android section of your tiapp.xml file:

Refer to Android Developers: Styles and Themes for detailed information on customizing items.

Material theme

Starting with Release 4.0.0, the Titanium SDK exposes the Material Theme color palette attributes, introduced in Android 5.0 (Lollipop). These attributes allow you to style the status bar, action bar and several control widgets, such as toggle switches and text fields, without having to individually style each component.

To use the Material Theme with Titanium, you need to create a custom theme that extends one of the AppCompat themes, then set the color palette attributes you want to change from the default theme (see the attribute table below). You will need to build your application with Android SDK 5.0 (API 21) and greater. Note that some of the attributes will not be applied when the application is ran on devices running previous versions of Android (pre-Lollipop) (see the comparison table below).

Example

The following XML file below defines a theme that uses the default AppCompat theme and applies additional color palette attributes. This theme was applied to the application in the previous screen shot.

Theme comparison

The following table compares the same application when using different Android versions and themes. Note that the Android 4.4. screenshots use the old style toggle button due to Android bug #78262.

Material theme further reading

• Android Developer: Using Material Theme
• Android Developers Blog: AppCompat v21 — Material Design for Pre-Lollipop Devices!
• Google Design Guidelines: Style - Color

Override a theme

If you have a global theme set, the application can override the theme for a window or activity, or if you want to specify a custom theme for a specific window or activity.

Override a window theme

Starting with Release 3.4.0, the Titanium SDK exposes the  theme property for Windows. Use the theme property to override the global theme for an individual window. Set the property to the name of the theme you want to apply to the window. The property can only be set when creating the Window object and cannot be changed after it is set.
NOTE: This method sets the theme for a window dynamically. In native Android doing so with a theme that has not been set for a particular Activity in the Manifest and a translucent background results in unstable behavior on different devices or OS versions. For instance the window may be solid black color and not showing any content. It is discouraged to use such themes dynamically.

Override an activity theme

As you can see in the previous examples, an application-wide theme can be specified in the <application> element of your tiapp.xml file, but it can also be overridden on a per-activity basis. These activities are defined in the AndroidManifest.xml file, generated by the build process. You can find the generated AndroidManifest.xml file in the build/android folder under your project folder. Inside the AndroidManifest.xml, you'll find code like this:

To override the theme for one of these activities, copy the activity definition into the tiapp.xml file, and place it inside the <android><manifest> element. The <activity> element must be nested inside an <application> element, as in the original AndroidManifest.xml file. The end result should look something like this:

Custom theme generator

Android Action Bar Style Generator

The Android Action Bar Style Generator is a website tool that builds and generates an Android Action Bar style based on the customizations you select.  This tool generates the XML files and graphic assets you need and packages them in to a ZIP file, which you can unpack in your project.

To create a custom Action Bar style:

1. Go to Android Action Bar Style Generator.
2. Enter a name for your style.  This name will be used to reference your style in the Android manifest.  If you want to use a theme generated by the Android Holo Colors Generator, do not use the same name.
   
3. For Style Compatibility, use AppCompat.
4. Choose the style customizations you want to use.
5. Click Download .ZIP button near the button of the web page to download your custom theme.

Once you have your custom Action Bar style, unpack the ZIP file and copy the res folder to your project's platform/android folder.  Then, modify your tiapp.xml file to use the custom style, for example:

Further reading

• Android Developers: Styles and Themes