The UI Composer is a tool for supporting the "Screen Layout" to implement the GUI using the UI Toolkit (Figure 1).

The layout and properties of widgets can be set visually; the work result will be output to a source code for the UI Toolkit.

Figure 1 UI Composer Overview

Figure 2 UI Development Flow Using the UI Composer

The development flow using the UI Composer is as follows.

1. Use the UI Composer to set the layout and properties of widgets.
2. Information of the layout, for example, will be output as a C# source code. The source code storing layout information will be separately output from the source codes for implementing application logic and the event handler.
3. Load the output source code into the project of the application to be created, and add codes for the application logic and event handler.
4. Build the application and test it on a simulator or on a device.