It is a visual technology to automate and test graphical user interfaces (GUI) using images (screenshots). The scripts you create with this tool are in the Sikuli Script language, which is a Python (Jython) extension. It also features Sikuli IDE which is an integrated development environment for writing visual scripts with screenshots easily.
There are plenty of examples and tutorials in its web site but most of them are intended for desktop operating systems. As usual here we will be focusing on its Android praxis.
Unlocking the emulator
Out example will be unlocking the emulator screen using some screenshots. That is, instead of guessing or finding out a-priori the coordinates of the touch events that are needed to achieve the goal of unlocking the screen we will use images.
The Sikuli IDE provides the means of obtaining the screenshots to complete the arguments of the specific methods.
For example, if you select the click() method to click over something, you are prompted to take a screenshot of an area of the screen that will be the target and the the IDE shows this thumbnail.
Instead of trying to describe it, it's worth showing you the IDE window to understand what I mean.
The idea is to click on the Android text, just to gain windows focus in case it was lost. The specific method to do this is App.focus("5554") assuming that "5554" appears in the emulator's window title, work on Windows and Linux but it doesn't work on Mac OSX.
Then we search the screen for the image of the lock button, when we find it we touch with the mouse, wait a little, and drag till the position of the unlock dot, where we move up.
Unlocking a pattern lock
The previous example was very illustrative, but sincerely it was a bit simple and could have been done with other tools too.
So, let's get things a bit more complicated as it is the phone locked by a pattern.
As before we take the screenshot of the pattern but this time we double click on it in the IDE to get the Pattern Settings window and there we set the Target Offset to follow the shape of the pattern. This is then identified by a red cross over the screenshot as follows:
When you run this script you can see how the pattern is completed and consequently the phone unlocked.
Pretty simple, right ?
Definitely something you should consider when automating GUI tests.