相当于iOS的Android共享首选项 [英] iOS Equivalent For Android Shared Preferences

问题描述

我正在将一个Android应用程序移植到iOS，我使用的一件事是Android中的共享的偏好设置"，用于在每次关卡完成时进行保存.

这样，当用户重新进入应用程序时，他们可以看到自己已达到3级或其他级别.

iOS中是否有类似的机制?还是我必须手动写出到特定于应用程序的文件?

如果是这样，我如何写出仅对我的应用程序可见的文件?

谢谢.

解决方案

使用 NSUserDefaults :-请注意，这是针对少量数据的，例如像您提到的当前水平.不要滥用它并将其用作大型数据库，因为无论您是否需要从应用程序中每次访问，它都会加载到内存中(应用程序的其他部分也将使用它).

Objective-C:

阅读:

NSUserDefaults *preferences = [NSUserDefaults standardUserDefaults];

NSString *currentLevelKey = @"currentlevel";

if ([preferences objectForKey:currentLevelKey] == nil)
{
    //  Doesn't exist.
}
else
{
    //  Get current level
    const NSInteger currentLevel = [preferences integerForKey:currentLevelKey];
}

写作:

NSUserDefaults *preferences = [NSUserDefaults standardUserDefaults];

NSString *currentLevelKey = @"currentlevel";

const NSInteger currentLevel = ...;
[preferences setInteger:currentLevel forKey:currentLevelKey];

//  Save to disk
const BOOL didSave = [preferences synchronize];

if (!didSave)
{
    //  Couldn't save (I've never seen this happen in real world testing)
}

.

快捷键:

阅读:

let preferences = NSUserDefaults.standardUserDefaults()

let currentLevelKey = "currentLevel"

if preferences.objectForKey(currentLevelKey) == nil {
    //  Doesn't exist
} else {
    let currentLevel = preferences.integerForKey(currentLevelKey)
}

写作:

let preferences = NSUserDefaults.standardUserDefaults()

let currentLevelKey = "currentLevel"

let currentLevel = ...
preferences.setInteger(currentLevel, forKey: currentLevelKey)

//  Save to disk
let didSave = preferences.synchronize()

if !didSave {
    //  Couldn't save (I've never seen this happen in real world testing)
}

I am porting an Android app to iOS, one thing I used was the Shared Preferences in Android to save each time a level was complete.

That way when the user gets back into the app, they can see they are up to level 3 or whatever.

Is there a similar mechanism in iOS? or do I have to manually write out to an application specific file?

If so, how do I write out to files only visible to my application?

Thanks.

解决方案

Use NSUserDefaults: - note that this is for small bits of data, such as the current level like you mentioned. Don't abuse this and use it as a large database, because it is loaded into memory every time you open your app, whether you need something from it or not (other parts of your app will also use this).

Objective-C:

Reading:

NSUserDefaults *preferences = [NSUserDefaults standardUserDefaults];

NSString *currentLevelKey = @"currentlevel";

if ([preferences objectForKey:currentLevelKey] == nil)
{
    //  Doesn't exist.
}
else
{
    //  Get current level
    const NSInteger currentLevel = [preferences integerForKey:currentLevelKey];
}

Writing:

NSUserDefaults *preferences = [NSUserDefaults standardUserDefaults];

NSString *currentLevelKey = @"currentlevel";

const NSInteger currentLevel = ...;
[preferences setInteger:currentLevel forKey:currentLevelKey];

//  Save to disk
const BOOL didSave = [preferences synchronize];

if (!didSave)
{
    //  Couldn't save (I've never seen this happen in real world testing)
}

.

Swift:

Reading:

let preferences = NSUserDefaults.standardUserDefaults()

let currentLevelKey = "currentLevel"

if preferences.objectForKey(currentLevelKey) == nil {
    //  Doesn't exist
} else {
    let currentLevel = preferences.integerForKey(currentLevelKey)
}

Writing:

let preferences = NSUserDefaults.standardUserDefaults()

let currentLevelKey = "currentLevel"

let currentLevel = ...
preferences.setInteger(currentLevel, forKey: currentLevelKey)

//  Save to disk
let didSave = preferences.synchronize()

if !didSave {
    //  Couldn't save (I've never seen this happen in real world testing)
}

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