something out of character start with a splash screen before segueing directly into a modal "loading" dialog. It's like they're spitting directly into my face. Why? Why do you hate me so much? I just want to use your app, I don't deserve this kind of hostility. No one does.
The 90s called, they'd like their UI metaphors back
Modal windows have always been a crutch. Windowed operating systems are by nature multithreaded, so to avoid apps "freezing" you execute time consuming tasks on background threads. This introduces complexity as the user can potentially interact with the UI between expected states.
The easiest solution for developers is to stick up a modal window that steals focus from the application and prevents users from interacting with the UI until the app completes the background task.
With great latency comes great responsibility
The ascent of the web as a platform largely eliminated these anachronisms. Page load times have a dramatic influence on how quickly people navigate away from a site. When page load latency is being measured in 10s or 100s of milliseconds, it's not surprising that splash screens and "loading" dialogs have all but disappeared.
The good news is that users have also gotten used to content being loaded dynamically. Most people won't bat an eyelid at a page which loads text first and updates the images afterwards. It's expected behaviour.
Users will use the time it takes getting past your splash screen uninstalling your app
It's ironic that a platform that has even less allowance for delay has seen the reintroduction of the dreaded "loading" dialog. Sadly too many devs have gotten lazy. It's harder to develop a UI that works smoothly and intuitively while data is loading or processing is being done, so many don't bother.
Don't be the lazy guy - "it's hard" isn't a valid excuse. Mobile users are incredibly impatient, phones are used on the move and users constantly switch between applications. To be successful you need to make startups and transitions fast and seamless.
- Asynchronous tasks. Make sure anything that could take longer than a small fraction of a second happens in a background thread (use ASyncTasks to help). Use a Service to run tasks that should be completed even if the Activity is killed.
- Branding fail. You want your app to seem an integral part of the device. Every time you show a splash screen you're reminding people that they're using an add-on -- an add-on they can replace with something less annoying.
- Lazy loading. Loading data takes time, particularly if you need to download it first (particularly over a mobile network). It's important that you have something to show as quickly as possible, so take the browser approach by displaying what you can get quickly. Follow that up with slower items such as images. Load additional content as required when users start scrolling down your list, taking the same approach of text first, images later.
- In-place updates. Don't clear all your data every time you pull an update from the server. Update, add, and remove items from your UI as new data becomes available. Same with updating existing layouts with images once they've been downloaded.
- Pre-fetching. If you've got multiple tabs or even Activities within your app, there's no reason to wait until the user changes their selection to start loading data. Pre-fetch the first page of data so that it's ready when the user switches to it.
- Save your state. Switching between apps should be seamless and instant. Save all your Activity state so your app can resume instantly.
- Caching. There's no reason to download the same image multiple times. Likewise, it's often better to show out of date information and update it quickly than showing nothing at all.
- Background loading. Use Services to perform updates and download data while your app isn't in the foreground. This can extend from small amounts of pre-fetching to regular updates, or complete offline support.
- Visual "loading" elements. Use visual elements like progress bars to indicate that you're in the process of getting an update.
- Disable unsupported actions. Some actions within your app might not make sense until all the data is loaded. Rather than block interactivity, disable actions that aren't possible.
If you're creating a fully immersive experience you may have good reason to use both splash screens and loading dialogs
There's always an exception. If you're engaging in an immersive experience (like a game or turn-by-turn navigation), you don't want to start until the environment is fully constructed. Developers can't use many of the tricks above like dynamic lazy loading, because users want to enjoy the complete experience right from the start. This is especially true of 3D environments like a FPS or Google Earth that rely on an OpenGL environment.
I remember playing California Games on a friends C64. It was loaded via the tape drive, so if anyone quit the game we'd spend the 15 minutes it took to reload in a diverting game of "beat the moron". While it's important to ensure the environment is fully complete before allowing users to explore it, there are still a few tricks you can use to ensure the wait isn't quite as painful.
- Cache any downloaded content.
- Dynamically pre-load as much data as possible during gameplay.
- Save and cache as much state data as possible to ensure players can resume from where they left off.
- Try to provide useful information (hints? instructions? cut scenes?) in inter-level "loading" screens or splash screens.
- Delay the longest pauses as long as possible. I should be able to start the game, change the settings, and navigate to "load saved game" without a significant wait.
For most apps, splash screens and modal loading dialogs now belong in the 1990s with 9600 baud modems and pashminas. Embrace the now.