May 27, 2012

The curious BlinkLayout

While reading the source code of Android's LayoutInflater class I found a hidden gem that seems to be quite unnoticed yet. Ladies and gentlemen I present you the mighty BlinkLayout. Views that are placed inside this ViewGroup blink at a rate of 500ms.

The BlinkLayout is an inner class of the LayoutInflater and can therefore only be used in a XML layout that will be parsed by a LayoutInflater instance. Due to the implementation it's only possible to use it as root node using the <blink> tag inside a XML layout.

It seems like the BlinkLayout is available since Android 4.0 and isn't used in the Android source code I observed. Maybe it was added for debugging reasons and was forgotten later.

The video above shows the BlinkLayout in action using the following layout XML:

The following snippet was used to inflate the layout and pass it to the activity: