- User defaults swift 3 update how to#
- User defaults swift 3 update archive#
- User defaults swift 3 update code#
If you want to store any other type of object, you should typically archive it to create an instance of NSData. You can store any object that is a property list (NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary). The UserDefaults class provides convenience methods for accessing common types such as floats, doubles, integers, Boolean values, and URLs. A default object must be a property list. It is usually safe to use UserDefaults, but NSUbiquitousKeyValueStore could cause issues if you are not careful. When considering using these NSObjects keep in mind how a user will use the app. You can apply the majority of what we discuss in regards to UserDefaults to NSUbiquitousKeyValueStore. It requires connection to iCloud unlike UserDefaults. You can store scalar values such as BOOL, as well as values containing any of the property list object types: NSNumber, NSString, NSDate, NSData, NSArray, and NSDictionary. NSUbiquitousKeyValueStore uses the iCloud key-value store to make preference, configuration, and app-state data available to every instance of your app on every device connected to a user’s iCloud account.
htps://en./wiki/Persistence_(computer_science) If you are not familiar, I highly suggest reading this wikipedia article. *Persistence refers to the characteristic of state that outlives the process that created it. To synchronize preferences and other data across a user’s connected devices, use NSUbiquitousKeyValueStore instead. User’s defaults are stored locally on a single device, and persisted*, for backup and restore. When you set a default value, it’s changed synchronously within your process, and asynchronously to persistent storage and other processes. Since we switched the order of our code, it sets the default to false last, which the playground remembers as our most recent default.Īccording to Apple, at runtime, you use UserDefaults objects to read the defaults that your app uses from a user’s defaults database. UserDefaults caches the information to avoid having to open the user’s defaults database each time you need a default value. This time the playground will output false.
User defaults swift 3 update code#
Once again, modify your code to only print the value of User Defaults: import Foundation This time it will output true first and false second. Switch the order from before in your playground and run again. The playground will remember the most recent default you set for "User Defaults", and output true. Modify your code to only print the value of User Defaults: import Foundation We repeat, however this time we set a value of true for the key "User Defaults" and when we print to console it now returns true. We request and print the value of a key "User Defaults" and it returns false (like we set). Next we set the user defaults key "User Defaults" to a value of false. Line by line, we import foundation so we can access the included UserDefaults NSObject. Here is a quick example of user defaults in action before we jump back into Apple's documentation. We won't need to create any additional files or import other frameworks after this point. If your tool bar is missing, just hit Option-Command-T, or go to View -> Show Toolbar.ĭelete all the code in the playground and replace it with import Foundation. You can open the tab by clicking the top right button on the tool bar. This solves a common error where the playground never compiles or runs. Once created, open the identity tab and confirm that Playground Settings are set to macOS. Go ahead and create a fresh playground so we can test how much and what types of data can be stored without distractions. Before we continue defining and analyzing user defaults, let's quickly see how they work in a playground. The user defaults are best used in small ways, but they can be quite vast.
The parameters are referred to as defaults because they’re commonly used to determine an app’s default state at startup or the way it acts by default. Apps store these preferences by assigning values to a set of parameters in a user’s defaults database.
For example, you can allow users to specify their preferred units of measurement or media playback speed. "User defaults are an interface to the user’s defaults database, where you store key-value pairs persistently across launches of your app."Īccording to Apple, the defaults system allows an app to customize its behavior to match a user’s preferences. I follow Apple's documentation closely in this article, often quoting directly, so if you'd like to first look through their documentation follow the link at the bottom of the article.
User defaults swift 3 update how to#
In this article, we will cover what user defaults are, how to use them, and why to use them. One of the easiest ways to store data locally is with user defaults.
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