从NSUserDefaults检索PSMultiValueSpecifier字符串

时间:2011-03-04 00:21:05

标签: iphone nsuserdefaults

我在Settings.bundle的Root.plist中使用multi_preference设置了一个首选项,如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>StringsTable</key>
    <string>Root</string>
    <key>PreferenceSpecifiers</key>
    <array>
        <dict>
            <key>Type</key>
            <string>PSMultiValueSpecifier</string>
            <key>Key</key>
            <string>multi_preference</string>
            <key>DefaultValue</key>
            <string>Show First Page</string>
            <key>Title</key>
            <string>My Option</string>
            <key>Identifier</key>
            <string>myOption</string>
            <key>Titles</key>
            <array>
                <string>Option 1</string>
                <string>Option 2</string>
            </array>
            <key>Values</key>
            <array>
                <string>Option 1</string>
                <string>Option 2</string>
            </array>
        </dict>
    </array>
</dict>
</plist>

当我尝试使用以下代码从列表中获取值时:

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *option = [defaults arrayForKey:@"myOption"];

我总是没有回来。

我正在使用模拟器,我在应用程序设置中设置了初始值。

任何人都有任何想法我错过了什么?

由于

iphaaw

2 个答案:

答案 0 :(得分:3)

对不起我之前的回答,我误解了这个问题。让我们再试一次。

查看the documentation的PSMultiValueSpecifier,NSUserPreferences的密钥存储在plist中的“Key”键中,而不是“Identifier”键。所以在这种情况下,[defaults arrayForKey:@"multi_preference"]应该可以为您提供价值。或者您可以像这样更改它,它应该与“myOption”一起使用:

    <dict>
        <key>Type</key>
        <string>PSMultiValueSpecifier</string>
        <key>Key</key>
        <string>myOption</string>
        <key>DefaultValue</key>
        <string>Option 1<string>
        <key>Title</key>
        <string>My Option</string>
        <key>Titles</key>
        <array>
            <string>Text for Option 1</string>
            <string>Text for Option 2</string>
        </array>
        <key>Values</key>
        <array>
            <string>Option 1</string>
            <string>Option 2</string>
        </array>
    </dict>

答案 1 :(得分:0)

请检查question

问题在于用户与应用程序设置进行交互之前,所选值为nil

解决方案是在应用启动时将默认值从Root.plist注册到UserDefaults

我已将原始问题的代码更新为Swift 5:

static func registerSettingsDefaults()
{
    // Get Settings bundle path
    guard let settingsBundle = Bundle.main.path(forResource: "Settings", ofType: "bundle") else {
        assertionFailure("Could not find Settings bundle")
        return
    }

    // Get settings plist
    let settings = NSDictionary(contentsOfFile: settingsBundle + "/Root.plist")

    // Get preferences dictionary
    guard let preferences = settings?.object(forKey: "PreferenceSpecifiers") as? [[String: Any]] else {
        assertionFailure("Could not find preferences")
        return
    }

    // Filter out default values from Settings
    var defaultsToRegister: [String: Any] = [:]
    preferences.forEach { dictionary in
        if let key = dictionary["Key"] as? String {
            defaultsToRegister[key] = dictionary["DefaultValue"] as? String
        }
    }

    UserDefaults.standard.register(defaults: defaultsToRegister)
}

我用didFinishLaunchingWithOptions称呼它:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool
{
    // Register Settings defaults
    registerSettingsDefaults()