自定义UINavigationBar的backButton？

Question

我正在制作一个iPhone应用程序,允许用户返回UINavigationBar.然而,它现在的样子是可怕的.我试图用我自己的图像(减去默认的UIBarButtonItem背景)来自定义它.我的图片包含我的自定义背景,但您仍然可以看到左侧和右侧的部分按钮.

UIBarButtonItem *cancelButton = [[[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"back_button_normal.png"] style:UIBarButtonItemStylePlain target:self   action:@selector(cancel:)] autorelease];
self.navigationItem.leftBarButtonItem = cancelButton;  

有没有办法删除那个空间？有没有可能我可以使用UIButton所以我可以完全自定义它？我在界面构建器中做了一些事情,我将UIButton拖入UINavigationBar的rightButton,它完美地运行.无论如何我可以通过编程方式进行吗？

谢谢!

以下是它的外观:

编辑#1:

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button addTarget:self action:@selector(cancel:) forControlEvents:UIControlEventTouchDown];
[button setTitle:@"Show View" forState:UIControlStateNormal];
[button setBackgroundImage:[UIImage imageNamed:@"back_button_normal.png"] forState:UIControlStateNormal];

UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
[self.navigationItem setLeftBarButtonItem:barButtonItem];

以下是我为UINavigationBar创建背景的方法(在我的RootViewController中):

@implementation UINavigationBar (UINavigationBarCustomDraw)

- (void) drawRect:(CGRect)rect {

[self setTintColor:[UIColor colorWithRed:0.85f green: 0.85f blue:0.85f alpha:1]];

if ([self.topItem.title length] > 0 && ![self.topItem.title isEqualToString:@"Back to ..."]) {
    [[UIImage imageNamed:@"UINavigationBar_background.png"] drawInRect:rect];

    CGRect frame = CGRectMake(0, 0, 320, 44);
    UILabel *label = [[[UILabel alloc] initWithFrame:frame] autorelease];
    [label setBackgroundColor:[UIColor clearColor]];
    label.font = [UIFont boldSystemFontOfSize: 20.0];
    label.shadowColor = [UIColor colorWithWhite:0.0 alpha:1];
    label.textAlignment = UITextAlignmentCenter;
    label.textColor = [UIColor whiteColor];
    label.text = self.topItem.title;
    self.topItem.titleView = label;

} else {
    [[UIImage imageNamed:@"login_button.png"] drawInRect:rect];
    self.topItem.titleView = [[[UIView alloc] init] autorelease];
}
}

@end

Answer 1

结合两个答案并添加了后退按钮功能

// Custom Navigation Bar Back Button

// Create Button
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom]; 
button.frame = CGRectMake(0,0,54,32); // width=54, height=32

// Set Button Image
NSString *backButtonURL = [[NSBundle mainBundle]pathForResource:@"back" ofType:@"png"];
UIImage *backButtonImage = [UIImage imageWithContentsOfFile:backButtonURL];
[button setBackgroundImage:backButtonImage forState:UIControlStateNormal];

// Important: Set Button Action to go back
[button addTarget:self.navigationController action:@selector(popViewControllerAnimated:) forControlEvents:UIControlEventTouchUpInside];

Answer 2

如果要UIButton通过obj-c 添加到导航栏,您的代码应如下所示:

UIButton *button = /* initialize your button */

UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
[self.navigationItem setLeftBarButtonItem:barButtonItem];