删除leftBarButtonItem背景

Question

如何删除leftBarButtonItem蓝色背景？ 我试过style:UIBarButtonItemStylePlain但没有结果。

代码：

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"icon_home"] style:UIBarButtonItemStylePlain target:self.navigationController action:@selector(openMenu) ];

Answer 1

    UIButton *tempButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [tempButton setFrame:CGRectMake(2, 1, 34, 34)]; // your Home Button Image width and height.
    [tempButton addTarget:self action:@selector(btnBackClicked:) forControlEvents:UIControlEventTouchUpInside];
    [tempButton setImage:[UIImage imageNamed:@"icon_home.png"] forState:UIControlStateNormal];
    [tempButton setImage:[UIImage imageNamed:@"icon_home_h.png"] forState:UIControlStateHighlighted];
    [self.navigationItem setLeftBarButtonItem:[[UIBarButtonItem alloc] initWithCustomView:tempButton]];

Answer 2

在你的案例中UINavigationController在管理导航栏和其中的UIBarButtonItems时会做一些额外的样式。因此，将样式设置为plain将与使用UIToolbar时的样式不同。

您需要的是自定义视图，例如......

UIImage *image = [UIImage imageNamed:@"icon_home"];
UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:imageView];
barButtonItem.target = self;
barButtonItem.action = @selector(openMenu);
self.navigationItem.leftBarButtonItem = barButtonItem;

此外，您可能希望target设置为self而不是self.navigationController。

Answer 3

如果你只关心iOS 5+，还有另一种不涉及自定义视图的方法。使用UIAppearance添加，您可以使用

UIImage * emptyImage() {
    UIGraphicsBeginImageContext(CGSizeMake(1, 1));
    UIImage * emptyImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return emptyImage;
}

UIBarButtonItem * item = [[UIBarButtonItem alloc] initWith...];
[item setBackgroundImage:emptyImage() forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
self.navigationItem.leftBarButtonItem = item;

如果这是应用程序范围的样式，请执行

[[UIBarButtonItem appearance] setBackgroundImage:emptyImage() forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];

一旦进入你的AppDelegate，你甚至不需要对个别实例大惊小怪。

Answer 4

UIButton *btn= [UIButton buttonWithType:UIButtonTypeCustom];
[btn setFrame:CGRectMake(0,0,30, 40)];    
[btn setImage:[UIImage imageNamed:@"icon_home.png"] forState:UIControlStateNormal];
[self.navigationItem setLeftBarButtonItem:[[UIBarButtonItem alloc] initWithCustomView:btn]];

这将工作请尝试....