Question

我想删除UIViewController后台按钮的背景。

我该怎么做？

我尝试了以下代码

backButton = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"back.png"] landscapeImagePhone:nil style:UIBarButtonSystemItemCancel target:self action:nil];
    [backButton setBackgroundImage:nil forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
self.navigationItem.backBarButtonItem = backButton;

但它不起作用！

Answer 1

不要试图修改UINavigationBar的后退按钮图像。这是不可能的，因为这是默认的。

而是将另一个自定义UIButton设置为UINavigationBar项，然后您可以根据需要自定义该项。

UIButton *btnItem = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 30, 30)];
[btnItem setTitle:@"title" forState:UIControlStateNormal];
[btnItem addTarget:self action:@selector(btnItem_click:) forControlEvents:UIControlEventTouchUpInside];
self.topItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithCustomView:btnItem];

Answer 2

UINavigation.backBarButtonItem不用于设置当前视图控制器的后退按钮，它用于从当前视图控制器推送的控制器的后退按钮。

现在说ViewController1正在UINavigationController中显示，您设置了backBarButton的{{1}}。后退按钮不会改变，但是当您按ViewController1时，您会看到ViewController2的后退按钮是您为ViewController2设置的内容。

要设置ViewController1的后退按钮，要么在ViewController中设置ViewController1，要么用户ViewController1，后者需要在YourButton上添加事件监听器

Answer 3

这段代码对我有用

UIImage *backButtonImage = [UIImage imageNamed:@"back.png"];
UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
[backButton addTarget:self action:@selector(backButtonPressed) forControlEvents:UIControlEventTouchUpInside];
[backButton setBackgroundImage:backButtonImage forState:UIControlStateNormal];
[backButton setFrame:CGRectMake(0, 0, 30, 30)];
UIBarButtonItem *backBarButton = [[UIBarButtonItem alloc] initWithCustomView:backButton];
[backBarButton setAction:@selector(backButtonPressed)];
self.navigationItem.leftBarButtonItem = backBarButton;
-(void)backButtonPressed{
    [self.navigationController popViewControllerAnimated:YES];
}

删除uibarbuttonitem后退按钮的背景图像

3 个答案: