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Setting default values for NSUserDefaults
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/* | |
UserDefaults (NSUserDefaults) is a go-to database for saving users' preferences over application behavior, | |
e.g., font size, sound disable/enable. So, most of the time, you want each of them to have a default value. | |
*/ | |
// Basic approach | |
let userDefaults = UserDefaults.standard | |
// 1 | |
if userDefaults.value(forKey: "enabledSound") == nil { | |
userDefaults.set(true, forKey: "enabledSound") | |
} | |
// 2 | |
if userDefaults.value(forKey: "enabledVibration") == nil { | |
userDefaults.set(true, forKey: "enabledVibration") | |
} | |
// The right approach with register(defaults:) | |
let userDefaults = UserDefaults.standard | |
// 1 | |
userDefaults.register( | |
defaults: [ | |
"enabledSound": true, | |
"enabledVibration": true | |
] | |
) | |
print(userDefaults.bool(forKey: "enabledSound")) // print true | |
// The value is only set if the key is nil | |
let userDefaults = UserDefaults.standard | |
// 1 | |
userDefaults.set(false, forKey: "enabledSound") | |
// 2 | |
userDefaults.register( | |
defaults: [ | |
"enabledSound": true, | |
"enabledVibration": true | |
] | |
) | |
print(userDefaults.bool(forKey: "enabledSound")) // print false | |
// The default values are not persist | |
let userDefaults = UserDefaults.standard | |
print(userDefaults.integer(forKey: "counter")) // print 0 | |
// 1 | |
userDefaults.register( | |
defaults: [ | |
"counter": 5 | |
] | |
) | |
print(userDefaults.integer(forKey: "counter")) // print 5 | |
// |
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