Android 4.0 requires default Holo theme for Android Market access
Google has announced that Android 4.0 "Ice Cream Sandwich" device manufacturers must implement custom user interface designs more transparently and include an unmodified standard theme. Only then will a device have access to the company's Android Market.
Android Framework engineer Adam Powell says that the primary aim is to simplify app development and support developers, noting that the measures are also designed to make it easier for manufacturers to update their devices to new Android versions. Powell points out that there are no plans to stop manufacturers creating custom user interfaces such as HTC Sense or Motorola's MOTOBLUR; these will continue to be possible and may be easier to implement in future.
App developers can apply a theme to all graphical elements in their apps or use the device's standard theme. However, the included themes may look slightly different on some devices because their vendors have customised them. This can create a need for elaborate testing and tricky layout modifications. Google hopes to prevent this by defining two new Android 4 themes: the Holo theme that was introduced in Android 3 "Honeycomb" must no longer be modified, and every device must implement a DeviceDefault theme that contains the manufacturer's customisations.
App developers can then either choose Holo, which should look the same on every device and saves a lot of testing, or they can use the DeviceDefault theme for the current device. Apps can also modify the user interface design independently of the themes as before. In the blog post, Powell provides a detailed explanation of how developers can use these new Android 3 and 4 features in apps that are also designed to run under Android 2.x.
- Android 4.0: New design, new features, a feature from The H.
- Google unwraps Android 4.0 "Ice Cream Sandwich", a report from The H.