When designing for multiple platforms the first consideration is probably the look and feel (see the Standard look and feel or app theme at the beginning of this chapter). However, it is also very important to consider whether your interface design will be easy to understand for your users (should it match the desktop widgets?). For a high-quality graphical application, it's important to consider how it will interact with the rest of the user's environment. For example, if your workflow included opening a web page outside the current interface, the expectation would probably be that it should open in the default web browser, which maybe configured by the operating system. Does the toolkit you selected handle opening web pages or other types of document specified by a URL? Will you instead need to write some code for each platform you wish to support to make the right thing happen?

To learn from the recent developments in mobile applications, we should look at the Share functionality. On Android, and more recently on iOS, an application can initiate a share action, and the platform toolkit will show an appropriate visual choice of ways to share that type of content. The user will then make their selection, and the application registered to handle that type of share will receive the content and request any further information required. How can native application developers of cross-platform applications provide similar functionality? If that is important to your application, then you could look for a language or toolkit that aims to provide this feature, but you may be left to try and implement it directly within your own code or to work with an external, web-based service to provide a similar experience.