使用 NSUserDefaults 更改 TintColor

Question

我的 UINavigationBar 中有一个 UIBarButtonItem。有一张星星的照片（白色的）。如果用户点击星星，我已经将星星的色调设置为黄色，作为最喜欢的星星的意思。如果用户点击一次白星，它会改变颜色，然后用户关闭应用程序。如果他确实点击它，我希望仍然选择该明星。它可以工作，但再次运行后不保存。有什么想法吗？

static UIBarButtonItem *barb1;
@interface ViewControllerDetail (){
    BOOL kokos;
}

-(void)changestarr{
if (kokos) {
            [barb1 setTintColor:[UIColor whiteColor]];
            kokos = NO;

        } else {
            [barb1 setTintColor:[UIColor yellowColor]];
            kokos = YES;
            prefs = [NSUserDefaults standardUserDefaults];
            [prefs setObject:[UIColor yellowColor] forKey:@"yess"];
            [prefs synchronize];
            NSString *message = @"You got it.";

            UIAlertView *toast = [[UIAlertView alloc] initWithTitle:nil
                                                            message:message
                                                           delegate:nil
                                                  cancelButtonTitle:nil
                                                  otherButtonTitles:nil, nil];
            [toast show];

            int duration = 1.7;

            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, duration * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
                [toast dismissWithClickedButtonIndex:0 animated:YES];

            });
        }}

Viewdidload

- (void)viewDidLoad
    {
        [super viewDidLoad];
        kokos = NO;
        barb1 =[[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"star.png"]
                                                                style:UIBarButtonItemStyleDone
                                                               target:self
                                                               action:@selector(changestarr)];

         barb2=[[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"final.png"]
                                                                style:UIBarButtonItemStyleDone
                                                               target:self
                                                             action:@selector(showfinal)];
        [barb1 setTintColor:[UIColor whiteColor]];

        self.navigationItem.rightBarButtonItems = [[NSArray alloc] initWithObjects:barb1, barb2, nil];

    }

Answer 1

你好，首先你应该设置你的第一个默认值。

-(void)setDefaults
{
 NSDictionary *dictionary = @{ @"BarButtonColor" : @1 }; // where 1 is white

 [[NSUserDefaults standardUserDefaults] registerDefaults:dictionary]; 

}

现在在视图控制器的 init 方法中调用 -(void)setDefaults。 然后将 -(void)viewDidLoad 更改为以下内容。

- (void)viewDidLoad
{
    [super viewDidLoad];

 // If you do not want to set defaults in init

 if ([[NSUserDefaults standardUserDefaults] integerForKey: @"BarButtonColor"] == 0) {
     [[NSUserDefaults standardUserDefaults] setInteger:1 forKey: @"BarButtonColor"];
     }



    kokos = NO; // Remove
    barb1 =[[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"star.png"]
                                                            style:UIBarButtonItemStyleDone
                                                           target:self
                                                           action:@selector(changestarr)];

     barb2=[[UIBarButtonItem alloc]initWithImage:[UIImage imageNamed:@"final.png"]
                                                            style:UIBarButtonItemStyleDone
                                                           target:self
                                                         action:@selector(showfinal)];
    // changes
    NSInteger color = [[NSUserDefaults standardUserDefaults] integerForKey: @"BarButtonColor"];

    if (color == 1) {
    [barb1 setTintColor:[UIColor whiteColor]];
    } else if (colour == 2) {
    [barb1 setTintColor:[UIColor yellowColor]];
    }

    // finished changes

    self.navigationItem.rightBarButtonItems = [[NSArray alloc] initWithObjects:barb1, barb2, nil];

}

然后最后把 -(void)changstarr 改成如下

-(void)changestarr{

NSInteger color = [[NSUserDefaults standardUserDefaults] integerForKey: @"BarButtonColor"];

if (color == 2) {
        [barb1 setTintColor:[UIColor whiteColor]];
        [[NSUserDefaults standardUserDefaults] setInteger:1 forKey:@"BarButtonColor"]];

    } else if (color == 1) {
        [barb1 setTintColor:[UIColor yellowColor]];
        [[NSUserDefaults standardUserDefaults] setInteger:2 forKey:@"BarButtonColor"]];
        NSString *message = @"You got it.";

        UIAlertView *toast = [[UIAlertView alloc] initWithTitle:nil
                                                        message:message
                                                       delegate:nil
                                              cancelButtonTitle:nil
                                              otherButtonTitles:nil, nil];
        [toast show];

        int duration = 1.7;

        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, duration * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
            [toast dismissWithClickedButtonIndex:0 animated:YES];

        });
    }}

如果应用程序意外终止，您可能需要进行错误检查。