以下方法无法识别 UIButton 选择器

Posted 2023-03-11

【中文标题】以下方法无法识别 UIButton 选择器

【英文标题】：UIButton selector not recognized by the following method

【发布时间】：2018-03-14 03:44:17

【问题描述】：

我在选择器上声明了一个方法，并创建了一个同名的方法。然而，该方法说它无法识别。错误信息：

- (void)viewDidAppear:(BOOL)animated 
    [super viewDidAppear:animated];

    UIImage *btnImage = [UIImage imageNamed:@"ic_favorite_border_48pt.png"];
    UIButton *heart = [UIButton buttonWithType:UIButtonTypeCustom];

    // get the image size and apply it to the button frame
    CGRect listButtonFrame = heart.frame;
    listButtonFrame.size = btnImage.size;
    heart.frame = listButtonFrame;

    [heart setImage:btnImage forState:UIControlStateNormal];
    [heart addTarget:self.navigationController.parentViewController
                   action:@selector(revealToggle:)
         forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *jobsButton =
    [[UIBarButtonItem alloc] initWithCustomView:heart];

    self.navigationItem.rightBarButtonItem = jobsButton;


    -(void)revealToggle:(UIButton *)heart
    

    

【问题讨论】：

Objective-C 不支持嵌套方法。

【参考方案1】：

您已将 revealToggle 方法放入您的 viewDidAppear 方法中。你不能那样做。把它移到外面。

- (void)viewDidAppear:(BOOL)animated 
    [super viewDidAppear:animated];

    UIImage *btnImage = [UIImage imageNamed:@"ic_favorite_border_48pt.png"];
    UIButton *heart = [UIButton buttonWithType:UIButtonTypeCustom];

    // get the image size and apply it to the button frame
    CGRect listButtonFrame = heart.frame;
    listButtonFrame.size = btnImage.size;
    heart.frame = listButtonFrame;

    [heart setImage:btnImage forState:UIControlStateNormal];
    [heart addTarget:self
                   action:@selector(revealToggle:)
         forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *jobsButton =
    [[UIBarButtonItem alloc] initWithCustomView:heart];

    self.navigationItem.rightBarButtonItem = jobsButton;


-(void)revealToggle:(UIButton *)heart

由于revealToggle 在同一个类中，您需要将self 作为目标传递。

【讨论】：

谢谢 rmaddy，你很敏锐。没想到我的方法在viewDidAppear里面，之前很疑惑。

我没看到 +1