rightbarbuttonitem不显示

Question

我有下面的代码来放置rightbarbuttonitem

UIButton* rightbutton = [UIButton buttonWithType:UIButtonTypeCustom];
    [rightbutton setBackgroundImage:[UIImage imageNamed:@"share-icon.png"] forState:UIControlStateNormal];
    [rightbutton addTarget:self action:@selector(share:) forControlEvents:UIControlEventTouchUpInside];
    self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithCustomView:rightbutton] autorelease];

但是它没有显示任何barbuttonitem。相反，如果我使用下面的代码，那么barbutton项就会出现，但问题是我不能用这个代码在barbuttonitem上设置触摸事件。

UIImageView *iconView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"dashboard-icon.png"]];
    UIBarButtonItem *icon = [[UIBarButtonItem alloc] initWithCustomView:iconView];
    self.navigationItem.leftBarButtonItem=icon;
    [icon release];
    [iconView release];

Answer 1

您是否已尝试为rightbutton设置适当的帧？例如rightbutton.frame = (CGRect){CGPointZero, image.size};

另请注意：

在iOS 4和更高版本上，指定文件扩展名时不需要文件名。在iOS 4之前，必须指定文件扩展名。

Answer 2

我的猜测是，您将UIBarButtonItem添加到了错误的对象！您需要将其添加到rootViewController (而不是像您可能已经做的那样添加到UINavigationController )

YourRootViewController *theRootController = [[YourRootViewController alloc] init];

UINavigationController* navContainer = [[UINavigationController alloc] initWithRootViewController:theRootController];

UIButton* rightbutton = [UIButton buttonWithType:UIButtonTypeCustom];
    [rightbutton setBackgroundImage:[UIImage imageNamed:@"share-icon.png"] forState:UIControlStateNormal];
    [rightbutton addTarget:self action:@selector(share:) forControlEvents:UIControlEventTouchUpInside];
 theRootController.navigationItem.rightBarButtonItem = rightbutton;

[navContainer setModalTransitionStyle:UIModalTransitionStyleCrossDissolve];
[self presentModalViewController:navContainer animated:YES];

Answer 3

如果你使用的是白色导航栏，别忘了在UIBarButtonItem上设置tintColor。我的纽扣就在那里，但是看不见。