具有自定义图像且无边框的 UIBarButtonItem

Question

我想创建一个带有自定义图像的 UIBarButtonItem，但我不想要 iPhone 添加的边框，因为我的图像有一个特殊的边框。

它与后退按钮相同，但前进按钮。

这个应用程序是针对内部项目的，所以我不在乎苹果是否拒绝或批准它或喜欢它:-)

如果我使用 UIBarButtonItem 的 initWithCustomView:v 属性，我可以做到这一点：

UIImage *image = [UIImage imageNamed:@"right.png"];

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setBackgroundImage: [image stretchableImageWithLeftCapWidth:7.0 topCapHeight:0.0] forState:UIControlStateNormal];
[button setBackgroundImage: [[UIImage imageNamed: @"right_clicked.png"] stretchableImageWithLeftCapWidth:7.0 topCapHeight:0.0] forState:UIControlStateHighlighted];

 button.frame= CGRectMake(0.0, 0.0, image.size.width, image.size.height);

[button addTarget:self action:@selector(AcceptData)    forControlEvents:UIControlEventTouchUpInside];

UIView *v=[[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, image.size.width, image.size.height) ];

[v addSubview:button];

UIBarButtonItem *forward = [[UIBarButtonItem alloc] initWithCustomView:v];

self.navigationItem.rightBarButtonItem= forward;

[v release];
[image release];

这可行，但如果我有在 10 个视图中重复这个过程，这不是 DRY。

我想我必须子类化，但是什么呢？

• NSView ？
• UIBarButtonItem ？

谢谢，

问候，

Answer 1

另一个简单的解决方案是

1. 拖动标准 UIButton
2. 将按钮的样式设置为自定义并设置该按钮的图像
3. 将其拖动到 UINavigationBar
4. 设置选择器上

Answer 2

您可以向 UIBarButtonItem 添加方法，而无需使用自定义类别对其进行子类化：

@interface UIBarButtonItem(MyCategory)

+ (UIBarButtonItem*)barItemWithImage:(UIImage*)image target:(id)target action:(SEL)action;

@end

@implementation UIBarButtonItem(MyCategory)

+ (UIBarButtonItem*)barItemWithImage:(UIImage*)image target:(id)target action:(SEL)action{
 // Move your item creation code here
}
@end

因此，您可以在代码中的任何位置创建调用此方法的栏项（前提是在其声明中包含标头）。

PS 您不需要使用 'v' UIView，因为您可以直接创建带有按钮的 UIBarButtonItem 作为自定义视图。
PPS 您的代码中还需要 [forward release]。

Answer 3

我发现这很容易。建议放在上面。 “random.png”必须在项目中。只需拖放任何图像即可。

 UIButton *a1 = [UIButton buttonWithType:UIButtonTypeCustom];
        [a1 setFrame:CGRectMake(0.0f, 0.0f, 25.0f, 25.0f)];
        [a1 addTarget:self action:@selector(randomMsg) forControlEvents:UIControlEventTouchUpInside];
        [a1 setImage:[UIImage imageNamed:@"config.png"] forState:UIControlStateNormal];
        UIBarButtonItem *random = [[UIBarButtonItem alloc] initWithCustomView:a1];

 //? line incomplete ?//   imageNamed:@"random.png"] style:UIBarButtonItemStylePlain target:self action:@selector(randomMsg)];

    self.navigationItem.rightBarButtonItem = random;

Answer 4

另一种方法是子类化 UIBarButtonItem。为什么？以便通过正确的发送者在目标上调用该操作。在上面的代码中，操作消息中的 sender 参数是 UIButton 实例，而不是 UIBarButtonItem 实例。例如，如果您希望从栏按钮项目中呈现 UIPopoverController，这将很重要。通过子类化 UIBarButtonItem，您可以添加一个保留原始目标的 ivar，从而允许我们的子类实例拦截、修改并向正确的发送者转发操作消息。

所以，CCFBarButtonItem.h：

#import <uIKit/UIBarButtonItem.h>

@interface CCFBarButtonItem : UIBarButtonItem
{
@protected
    id _originalTarget;
}
- (id)initWithImage:(UIImage *)image target:(id)target action:(SEL)action;
@end

和CCFBarButtonItem.m

#import "CCFBarButtonItem.h"
#import <UIKit/UIButton.h>
#import <UIKit/UIView.h>
#import <UIKit/UIImage.h>

@implementation CCFBarButtonItem

#pragma mark - Object life cycle

- (id)initWithImage:(UIImage *)image target:(id)target action:(SEL)action;
{
    _ASSIGN( _originalTarget, target );

    UIButton *imgButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [imgButton setImage:image forState:UIControlStateNormal];
    imgButton.frame = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
    [imgButton addTarget:self action:action forControlEvents:UIControlEventTouchUpInside];

    self = [super initWithCustomView:imgButton];

    return self;
}

- (void)dealloc;
{
    MCRelease(_originalTarget);
    [super dealloc];
}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector;
{
    if( [_originalTarget respondsToSelector:aSelector] )
    {
        return [_originalTarget methodSignatureForSelector:aSelector];
    }
    else
    {
        return [super methodSignatureForSelector:aSelector];
    }
}

- (void)forwardInvocation:(NSInvocation *)anInvocation;
{
    SEL aSelector = [anInvocation selector];
    if( [_originalTarget respondsToSelector:aSelector] )
    {
        //  modify the 'sender' argument so that it points to self
        [anInvocation setArgument:&self atIndex:2];
        [anInvocation invokeWithTarget:_originalTarget];
    }
    else
    {
        [self doesNotRecognizeSelector:aSelector];
    }
}
@end

Answer 5

UIBarButtonItem *menuItem = [[UIBarButtonItem alloc] initWithImage: [UIImage imageNamed:@"icon-menu.png"]
                                                                    style:UIBarButtonItemStylePlain
                                                                   target:self
                                                                   action:@selector(showMenu)];

Answer 6

这也可以通过编程来完成（当然）：

首先，创建一个自定义视图。此自定义视图可以包含图像、按钮或您想要的任何其他内容。自定义视图可以通过编程方式或在 IB 中创建：

UIImage *customImage = [UIImage imageNamed:@"imageName"];
UIView *customView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, customImage.size.width, customImage.size.height)];
customView.backgroundColor = [UIColor colorWithPatternImage:customImage];

接下来，创建一个 UIBarButtonItem 并使用自定义视图对其进行初始化。

UIBarButtonItem *customBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:customView];

现在，只需将自定义 UIBarButton 添加到 leftBarButtonItem：

self.navigationItem.leftBarButtonItem = customBarButtonItem;

Answer 7

好吧，这个类别工作得很好，因为 Popovercontroller 没有问题:-)

#import <UIKit/UIKit.h>

@interface UIBarButtonItem (BarButtonItemExtended)
+ (UIBarButtonItem*)barItemWithImage:(UIImage*)image target:(id)target action:(SEL)action;
-(void)performBarButtonAction:(id)sender;
@end



#import "UIBarButtonItem+BarButtonItemExtended.h"

@implementation UIBarButtonItem (BarButtonItemExtended)

+ (UIBarButtonItem*)barItemWithImage:(UIImage*)image target:(id)target action:(SEL)action
{    
    UIButton *imgButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [imgButton setImage:image forState:UIControlStateNormal];
    imgButton.frame = CGRectMake(0.0, 0.0, image.size.width, image.size.height);

    UIBarButtonItem *b = [[UIBarButtonItem alloc]initWithCustomView:imgButton];

    [imgButton addTarget:b action:@selector(performBarButtonAction:) forControlEvents:UIControlEventTouchUpInside];

    [b setAction:action];
    [b setTarget:target];

    return b;
}

-(void)performBarButtonAction:(UIButton*)sender
{
    [[self target] performSelector:self.action withObject:self];
}
@end

Answer 8

另一种解决方案，认为在以编程方式创建按钮时更简单：

UIBarButtonItem *button = [[UIBarButtonItem alloc] initWithImage:defaultImage
                                             landscapeImagePhone:landscapeImage
                                                           style:UIBarButtonItemStylePlain
                                                          target:self
                                                          action:@selector(someSelector)];
[button setBackgroundImage:[UIImage new] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[button setBackgroundImage:[UIImage new] forState:UIControlStateNormal barMetrics:UIBarMetricsLandscapePhone];

Answer 9

检查这个简单的解决方案。

- (void)splitViewController:(UISplitViewController *)splitController willHideViewController:(UIViewController *)viewController withBarButtonItem:(UIBarButtonItem *)barButtonItem forPopoverController:(UIPopoverController *)popoverController
{
barButtonItem.image = [UIImage imageNamed:@"navButton.png"];
barButtonItem.style = UIBarButtonItemStylePlain;

[barButtonItem setBackgroundImage:[UIImage imageNamed:@"1x1.png"] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[self.navigationItem setLeftBarButtonItem:barButtonItem animated:YES];
self.masterPopoverController = popoverController;
}

这里 1x1.png 是一个 1 像素透明 png 图像，您可以从下面的链接下载：

http: //commons.wikimedia.org/wiki/File:1x1.png