Xcode/iOS NSUserDefaults 行为奇怪

Question

我正在尝试使用 NSUserDefaults 进行我的第一个保存项目，但发生了一些奇怪的事情。

在我的应用程序委托中，在做太多事情之前，我会切换几个变量。

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

if (![defaults objectForKey:@"firstRun"]){
    //flag doesnt exist then this IS the first run
    self.firstRun = TRUE;

    NSLog(@"FIRST RUN");

    //store the flag so it exists the next time the app starts
    [defaults setObject:[NSDate date] forKey:@"firstRun"];
    NSLog(@"%s world2 before",[defaults objectForKey:@"world2"] ? "true" : "false" );
    [defaults setBool:false forKey:@"world2"];
    NSLog(@"%s world2 after",[defaults objectForKey:@"world2"] ? "true" : "false" );
}else{
    //flag does exist so this ISNT the first run
    self.firstRun = FALSE;
    NSLOG(@"NOT FIRST RUN");
    NSLog(@"%s world2",[defaults objectForKey:@"world2"] ? "true" : "false" );

}
[[NSUserDefaults standardUserDefaults] synchronize];

这样做，当我运行应用程序时，这就是我在控制台中得到的（第一次运行时）

2014-09-09 22:15:57.794 GameName[30151:907] FIRST RUN
2014-09-09 22:15:57.795 GameName[30151:907] false world2 before
2014-09-09 22:15:57.795 GameName[30151:907] true world2 after

我不明白为什么在将其设置为假之前，它是假的（当然，好的） - 但在将其设置为假之后，它是真的！嗯？

我也尝试过设置为 true、YES、NO，以及将 NSNumber 与 Bool 一起使用。

我的完整应用委托：

.h

#import <UIKit/UIKit.h>
#import "cocos2d.h"
#import "GameLevelLayer.h"
@interface AppController : CCAppDelegate
{
    GameLevelLayer *currentLevel;
}
@property(nonatomic) BOOL firstRun;


@end

.m

#import "cocos2d.h"

#import "AppDelegate.h"
#import "CCBuilderReader.h"


@implementation AppController
@synthesize firstRun = _firstRun;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:        (NSDictionary *)launchOptions
{
    // Configure Cocos2d with the options set in SpriteBuilder
    NSString* configPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"Published-iOS"]; // TODO: add support for Published-Android support
    configPath = [configPath stringByAppendingPathComponent:@"configCocos2d.plist"];

    NSMutableDictionary* cocos2dSetup = [NSMutableDictionary dictionaryWithContentsOfFile:configPath];

    // Note: this needs to happen before configureCCFileUtils is called, because we need apportable to correctly setup the screen scale factor.
#ifdef APPORTABLE
    if([cocos2dSetup[CCSetupScreenMode] isEqual:CCScreenModeFixed])
        [UIScreen mainScreen].currentMode = [UIScreenMode emulatedMode:UIScreenAspectFitEmulationMode];
    else
    [UIScreen mainScreen].currentMode = [UIScreenMode emulatedMode:UIScreenScaledAspectFitEmulationMode];
#endif

    // Configure CCFileUtils to work with SpriteBuilder
    [CCBReader configureCCFileUtils];

    // Do any extra configuration of Cocos2d here (the example line changes the pixel format for faster rendering, but with less colors)
    //[cocos2dSetup setObject:kEAGLColorFormatRGB565 forKey:CCConfigPixelFormat];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    if (![defaults objectForKey:@"firstRun"]){
        //flag doesnt exist then this IS the first run
        self.firstRun = TRUE;

        NSLog(@"FIRST RUN");

        //store the flag so it exists the next time the app starts
        [defaults setObject:[NSDate date] forKey:@"firstRun"];
        NSLog(@"%s world2 before",[defaults objectForKey:@"world2"] ? "true" : "false" );
        [defaults setBool:false forKey:@"world2"];
        NSLog(@"%s world2 after",[defaults objectForKey:@"world2"] ? "true" : "false" );
    }else{
        //flag does exist so this ISNT the first run
        self.firstRun = FALSE;
        NSLog(@"NOT FIRST RUN");
        NSLog(@"%s world2",[defaults objectForKey:@"world2"] ? "true" : "false" );

    }
    [[NSUserDefaults standardUserDefaults] synchronize];

    [self setupCocos2dWithOptions:cocos2dSetup];

    return YES;
}

Answer 1

看来日志条件不正确。您正在使用“setBool”方法设置值。在检索您使用“objectForKey”方法时。

[defaults objectForKey:@"world2"] ? "true" : "false";

上述行返回“true”，因为它检查用户默认值是否具有键“world2”的值。因此，将该行更改为

 [defaults boolForKey:@"world2"] ? "true" : "false"

Answer 2

你需要使用：

- (BOOL)boolForKey:(NSString *)defaultName

不是：

- (id)objectForKey:(NSString *)defaultName

后者返回一个对象，表示 false，因此NSLog() 中的测试报告 true 表示返回了某些内容。

所以代码是：

[defaults boolForKey:@"world2"]