如何使以编程方式创建的 leftBarButtonItem 可见并设置 backgroundimage答案

【问题标题】：How to make visible a leftBarButtonItem created programmatically and set backgroundimage如何使以编程方式创建的 leftBarButtonItem 可见并设置 backgroundimage
【发布时间】：2012-11-26 08:52:53
【问题描述】：

以下代码在我的应用程序中运行良好。但是那个 leftbarbuttonitem 是不可见的。而且我无法将背景图像设置为leftBarButtonItem。我做错了什么，但我不知道是什么错误？是否可以使背景图像可见并设置？

UIImageView *NavigationBarImage =[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 320, 44)];
NavigationBarImage.image=[UIImage imageNamed:@"mapbutton.png"];
[self.navigationController.navigationBar addSubview:NavigationBarImage];
self.navigationItem.hidesBackButton = YES;

UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonItemStyleBordered target:self action:@selector(goBack)];
self.navigationItem.leftBarButtonItem = backButton;

-(void)goBack
{
    [self.navigationController popViewControllerAnimated:YES];
}

【问题讨论】：

标签： iphone objective-c uinavigationcontroller uinavigationitem

【解决方案1】：

如果您想为导航项添加背景图像，您必须添加自定义按钮，如下所示：

UIButton *tempButton                            =       [UIButton buttonWithType:UIButtonTypeCustom];
tempButton.frame                                =       CGRectMake(0, 0, 50, 30);
tempButton.showsTouchWhenHighlighted            =       YES;
tempButton.backgroundColor                      =       [UIColor clearColor];
[tempButton setBackgroundImage:[UIImage imageNamed:@"back.png"] forState:UIControlStateNormal];
[tempButton setTitle:@"Back" forState:UIControlStateNormal];
[tempButton addTarget:self action:@selector(goBack) forControlEvents:UIControlEventTouchUpInside];

UIBarButtonItem *backBtn                        =         [[UIBarButtonItem alloc]initWithCustomView:tempButton];

self.navigationItem.leftBarButtonItem           =       backBtn;

要为导航栏添加背景图片，您可以使用以下代码

 [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"header.png"] forBarMetrics:UIBarMetricsDefault];

【讨论】：

非常感谢您的回复.. 但现在 leftbarbuttonitem 也是不可见的
- (void)viewDidLoad { [super viewDidLoad]; UIButton *tempButton = [UIButton buttonWithType:UIButtonTypeCustom]; tempButton.frame = CGRectMake(0, 0, 30, 30); tempButton.showsTouchWhenHighlighted = YES; tempButton.backgroundColor = [UIColor clearColor];
[tempButton setBackgroundImage:[UIImage imageNamed:@"food.png"] forState:UIControlStateNormal]; [tempButton addTarget:self action:@selector(goBack) forControlEvents:UIControlEventTouchUpInside]; UIBarButtonItem *backBtn = [[UIBarButtonItem alloc]initWithCustomView:tempButton]; self.navigationItem.leftBarButtonItem = backBtn; [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"mapsnav.png"] forBarMetrics:UIBarMetricsDefault]; self.navigationItem.hidesBackButton = YES;self.view.backgroundColor=[UIColor colorWithPatternImage:[UIImage imageNamed:@"background.png"]];}
您的 viewdidload 看起来不错，您的导航栏是否可见，或者您可以向我发送您的项目，然后我可以调试它。如果你想给我发电子邮件 imneev@gmail.com

【解决方案2】：

UIButton *home = [UIButton buttonWithType:UIButtonTypeCustom];  
UIImage *homeImage = [UIImage imageNamed:@"YOUR_IMAGE.png"];  
[home setBackgroundImage:homeImage forState:UIControlStateNormal];  
[home addTarget:self action:@selector(your_Action)  
forControlEvents:UIControlEventTouchUpInside];  
home.frame = CGRectMake(0, 0, 69, 26);  
UIBarButtonItem *button2 = [[UIBarButtonItem alloc] initWithCustomView:home];
[[self navigationItem] setLeftBarButtonItem:button2];
[button2 release];
button2 = nil;

【讨论】：