Question

在第一个nib viewController上向导航栏添加一个按钮，并希望仅在主屏幕上查看此按钮，而不是在任何其他屏幕上我已经解决了我做了按钮并添加到导航栏的子视图在每个按钮动作我已经把这个

- (IBAction)forth:(id)sender {
    forthView *forthview = [[forthView alloc]init];
    [self.navigationController pushViewController:forthview animated:YES];
    btn.hidden = YES;
}

这个按钮隐藏后但是当我回到主屏幕时没有出现我的viewdidload代码在这里

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    self.title = @"My First View";

    self.navigationController.navigationBar.barStyle = UIBarStyleBlackTranslucent;
    btn = [[UIButton alloc] init];

    btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn.frame = CGRectMake(10, 10, 65, 30);
    [btn setTitle:@"Show" forState:UIControlStateNormal];
    [self.navigationController.navigationBar addSubview:btn];

    btn.hidden = false;

}

Answer 1

隐藏按钮后，您需要再次取消隐藏按钮。这是取消隐藏按钮的简单代码：

btn.hidden = No

Answer 2

viewDidLoad仅在您第一次加载视图时调用。如果要测试何时调用它，请添加NSLog()语句。每次调用屏幕上显示的视图viewWillAppear时都会被调用所以你需要在viewWillAppear

中显示按钮

Answer 3

您真正希望做的是向主视图控制器的UIBarButtonItem属性添加navigationItem.leftBarButtonItem。这样，按钮将具有正确的外观，并在显示视图控制器时显示和隐藏。

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"Show"
                                                                         style:UIBarButtonItemStyleBordered
                                                                        target:self
                                                                        action:@selector(onShowButtonPressed:)];

如何将按钮添加到导航栏

3 个答案: