App state, start to finish (HTML)
[ This article is for Windows 8.x and Windows Phone 8.x developers writing Windows Runtime apps. If you’re developing for Windows 10, see the latest documentation ]
Save and restore app data and the UI state of your Windows Store app so that users can pick up right where they left off.
Many users spread their work and play across multiple devices and apps, so matching the life cycle of your Windows Store app to their increasingly dynamic lifestyle is more important than ever. Users now expect your app to remember many aspects of its state—not just the main content and basic user data—as they multitask on their PC.
For example, when users come back to your app after it has been suspended, they expect it to resume on the same page it was on when they left. They expect the page to be scrolled to the same position and all of its controls to be in the same state as before, including content, text and item selection, scroll position, and input focus. They also expect your app to remember the state of previously visited pages so that they can navigate back and forward as before.
To make this experience possible, your app has to persist elements of the app state (like app settings and UI selections) through each of these stages of the app life cycle:
App suspension
An app is suspended when the user switches away from it or when Windows enters a low-power state. Most apps stop running when the user switches away from them.
App termination
An app is considered terminated if the user decides to close it or if it crashes.
App launch on a different device
Users who are signed in to another Windows 8 device with the same Microsoft account that your app was activated with can deploy and launch your app on that device.
Many elements of app state, including most control property values, require little effort to save and restore. But preserving other kinds of app state requires more complex code or specialized techniques. For example, you can't save and roam a user password the same way you would the contents of regular text box. In general, you must balance trade-offs between simplicity, security, performance, and data integrity, depending on your specific app requirements.
Using guidelines, best practices, and code examples, we'll help you make the right choices about what elements of the app state to save and what techniques to use for the different kinds of state.
Tip Check out the App data sample to see a comprehensive code example that shows basic types of app data and your options for storing and making it discoverable.
Step 1: Understand the Windows Store app life cycle
Before you can plan how your app will handle its data during a single app session or multiple app sessions, it's important to understand the end-to-end Windows Store app life cycle.
.jpg "start icon") |
Learn about the life cycle of a Windows Store app, from the time it's deployed through its removal. |
.jpg "step icon") |
Guidelines for app suspend and resume Get user-experience recommendations to help you design the suspend and resume behavior of your app. |
Step 2: Define app behavior for activation, suspend, and resume events
Define specific app behaviors for critical life-cycle events: app activation, suspension, and resume.
|
Learn how to define the activation experience for your app. |
|
Learn how to save important app data when the system suspends your app. |
|
Learn how to refresh displayed content when the system resumes your app. |
Step 3: Identify app data and how you want to save it
Learn about the different types of app data and your options for storing it. Understand the differences between local, roaming, and temporary app data storage so you can create a data experience that's perfect for your app and its users.
|
Find out about the different types of app data and the different locations you can store it. |
|
Accessing app data with the Windows Runtime Learn about the local, roaming, and temporary data stores available to your app. |
|
Guidelines for roaming app data Get user-experience recommendations to help you take best advantage of data roaming. |
|
Store and retrieve settings and files from the local app data store. |
|
Store and retrieve settings and files from the roaming app data store. |
|
Quickstart: Temporary app data Store and retrieve settings and files from the temporary app data store. |
Step 4: Index local app data for Search
Now that you've settled on your app's behavior and how to manage app data, it's time to make sure that all of the unique data provided by your app is discoverable via local search on a Windows 8 PC.
|
Find out how to make your local app data searchable. |
|
How to perform rich queries on app local data Learn how to search files in the app data store. |
|
Understand how an app's navigation structure works with the app life cycle and data stores. |
Step 5: Wrap it up
Finally, confirm that your Windows Store app meets primary Windows Store certification requirements. Make this a part of your regular debugging and testing process to catch issues before you begin the Windows Store onboarding process.
.jpg "store requirements icon") |
Run the Windows App Certification Kit Run the Windows App Certification Kit to help ensure your app fulfills Windows Store requirements. Do this whenever you add major functionality to your app. |
.jpg "stop icon") |
You’re done! You’ve added important app state and data features to your Windows Store app to help create a reliably smooth user experience. |
Want to know more?
-
Learn more about determining the experience you want to provide to your users.
-
Browse the full list of user-experience guidelines.
-
Find out more about designing great user experiences.
Create your first Windows Store app
Follow this tutorial series if you're new to Windows Store app development and want to get started with your first app.
-
Learn more about designing Windows Store app UI.
Roadmap for Windows Store apps using C# and Visual Basic and Roadmap for Windows Store apps using C++
Find lots more about creating Windows Store apps using C++, C#, or Visual Basic in general.