Objective c 目标C下拉菜单如何更改属性标题？

我是iOS编程的新手。今天，我在中下载并使用MKDropdownMenu

我无法更改导航栏中MKDropdownMenu的标题。我希望当用户更改所选行时，此文本将被更改

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请帮帮我！谢谢

首先，声明一个NSString属性

@property（强，非原子）NSString*navTitle

将默认导航标题设置为
-（void）viewDidLoad
类似

_navTitle=@“MKDropdownMenu”

更改
-（NSAttributedString*）下拉菜单：（MKDropdownMenu*）下拉菜单attributedTitleForComponent:（NSInteger）component
方法如下-

- (NSAttributedString *)dropdownMenu:(MKDropdownMenu *)dropdownMenu attributedTitleForComponent:(NSInteger)component {

        return [[NSAttributedString alloc] initWithString:_navTitle
                                               attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:18 weight:UIFontWeightLight],
                                                            NSForegroundColorAttributeName: [UIColor whiteColor]}];
}

- (void)dropdownMenu:(MKDropdownMenu *)dropdownMenu didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *colorString = self.colors[row];
    self.textLabel.text = colorString;
    _navTitle = colorString;

    [self.navigationItem setTitle:colorString];

    UIColor *color = UIColorWithHexString(colorString);
    self.view.backgroundColor = color;
    self.childViewController.shapeView.strokeColor = color;

    delay(0.15, ^{
        [dropdownMenu closeAllComponentsAnimated:YES];
        [dropdownMenu reloadAllComponents];
    });
}

然后更改
-（void）dropdown菜单：（mkdropdown菜单*）dropdown菜单didSelectRow:（NSInteger）row inComponent:（NSInteger）component
，如下所示-

- (NSAttributedString *)dropdownMenu:(MKDropdownMenu *)dropdownMenu attributedTitleForComponent:(NSInteger)component {

        return [[NSAttributedString alloc] initWithString:_navTitle
                                               attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:18 weight:UIFontWeightLight],
                                                            NSForegroundColorAttributeName: [UIColor whiteColor]}];
}

- (void)dropdownMenu:(MKDropdownMenu *)dropdownMenu didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *colorString = self.colors[row];
    self.textLabel.text = colorString;
    _navTitle = colorString;

    [self.navigationItem setTitle:colorString];

    UIColor *color = UIColorWithHexString(colorString);
    self.view.backgroundColor = color;
    self.childViewController.shapeView.strokeColor = color;

    delay(0.15, ^{
        [dropdownMenu closeAllComponentsAnimated:YES];
        [dropdownMenu reloadAllComponents];
    });
}

首先，声明一个NSString属性
@property（强，非原子）NSString*navTitle

将默认导航标题设置为
-（void）viewDidLoad
类似

_navTitle=@“MKDropdownMenu”

更改
-（NSAttributedString*）下拉菜单：（MKDropdownMenu*）下拉菜单attributedTitleForComponent:（NSInteger）component
方法如下-

- (NSAttributedString *)dropdownMenu:(MKDropdownMenu *)dropdownMenu attributedTitleForComponent:(NSInteger)component {

        return [[NSAttributedString alloc] initWithString:_navTitle
                                               attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:18 weight:UIFontWeightLight],
                                                            NSForegroundColorAttributeName: [UIColor whiteColor]}];
}

- (void)dropdownMenu:(MKDropdownMenu *)dropdownMenu didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *colorString = self.colors[row];
    self.textLabel.text = colorString;
    _navTitle = colorString;

    [self.navigationItem setTitle:colorString];

    UIColor *color = UIColorWithHexString(colorString);
    self.view.backgroundColor = color;
    self.childViewController.shapeView.strokeColor = color;

    delay(0.15, ^{
        [dropdownMenu closeAllComponentsAnimated:YES];
        [dropdownMenu reloadAllComponents];
    });
}

然后更改
-（void）dropdown菜单：（mkdropdown菜单*）dropdown菜单didSelectRow:（NSInteger）row inComponent:（NSInteger）component
，如下所示-

- (NSAttributedString *)dropdownMenu:(MKDropdownMenu *)dropdownMenu attributedTitleForComponent:(NSInteger)component {

        return [[NSAttributedString alloc] initWithString:_navTitle
                                               attributes:@{NSFontAttributeName: [UIFont systemFontOfSize:18 weight:UIFontWeightLight],
                                                            NSForegroundColorAttributeName: [UIColor whiteColor]}];
}

- (void)dropdownMenu:(MKDropdownMenu *)dropdownMenu didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *colorString = self.colors[row];
    self.textLabel.text = colorString;
    _navTitle = colorString;

    [self.navigationItem setTitle:colorString];

    UIColor *color = UIColorWithHexString(colorString);
    self.view.backgroundColor = color;
    self.childViewController.shapeView.strokeColor = color;

    delay(0.15, ^{
        [dropdownMenu closeAllComponentsAnimated:YES];
        [dropdownMenu reloadAllComponents];
    });
}