- Human Interface Guidelines
- Design Philosophy
- User Workflow
- Desktop Integration
- UI Toolkit Elements
When a user launches an app, they're performing an explicit action and expecting a fast, oftentimes immediate response. You should focus on three key areas for app launching: speed, obviousness of what to do next, and state.
As has been said before, speed, especially when launching an app, is very important. There should be as little delay as possible in between the time a user decides to launch an app and the instant they can begin using it. If your app requires a splash screen, you're doing it wrong.
When a user launches your app, they should know exactly what to do next. This is achieved by following the other interface guidelines (ensuring your app is consistent with other apps) and by offering up explicit actions from the get go. If the app typically displays "items," such as songs or emails, let the user get at those items by displaying them when the app opens. If there are no previously-opened items, you should offer to open or create a new item (such as a document) by using a welcome screen.
If the user has previously used your app, it's typically best to restore the state of the app when opening it again. This means the app comes up to right where the user left off so they can pick up their work again. For a music player, this means opening up with the view where the user left it and the song paused where the user closed the app. For a document editor, this would mean opening up with the same document scrolled to the same spot with the cursor in the same spot on the page.