我如何自定义导航返回按钮在iOS 7及以上没有标题?(即只使用箭头)
self.navigationItem.leftBarButtonItem = self.editButtonItem;
我只是想知道它们是否有self。backbuttonitem;
OR
像这样的东西?
self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemBACK
target:self action:@selector(back)];
当前回答
虽然Kyle Begeman的回答完全做到了，但在每个视图控制器中都使用这种代码是相当烦人的。我最终得到了一个简单的UINavigationItem类别。小心，这里有龙!抱歉，我的意思是:
#import <objc/runtime.h>
@implementation UINavigationItem (ArrowBackButton)
static char kArrowBackButtonKey;
+ (void)load {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
Method m1 = class_getInstanceMethod(self, @selector(backBarButtonItem));
Method m2 = class_getInstanceMethod(self, @selector(arrowBackButton_backBarButtonItem));
method_exchangeImplementations(m1, m2);
});
}
- (UIBarButtonItem *)arrowBackButton_backBarButtonItem {
UIBarButtonItem *item = [self arrowBackButton_backBarButtonItem];
if (item) {
return item;
}
item = objc_getAssociatedObject(self, &kArrowBackButtonKey);
if (!item) {
item = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStyleBordered target:nil action:NULL];
objc_setAssociatedObject(self, &kArrowBackButtonKey, item, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
return item;
}
@end
其他回答
这是有效的，但它会删除前一项的标题，即使你弹出回到它:
self.navigationController.navigationBar.topItem.title = @"";
只需要在推送视图控制器的viewDidLoad上设置这个属性。
你可以把这个类别放在AppDelegate中。m文件。 移除UINavigation中所有默认后退按钮的文本。只有箭头“<”或设置自定义图像，如果你需要。
objective - c:
...
@end
@implementation UINavigationItem (Extension)
- (UIBarButtonItem *)backBarButtonItem {
return [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];
}
@end
我从iOS 5开始就一直在使用这个解决方案，没有任何问题。我在视图控制器中调用了一个实用函数。你需要在viewDidLoad或之后的任何点中做。
void updateBackButtonTextForViewController(UIViewController *viewController, NSString *text)
{
if(! viewController.navigationItem.backBarButtonItem)
{
viewController.navigationItem.backBarButtonItem =
[[UIBarButtonItem alloc] initWithTitle:text
style:UIBarButtonItemStylePlain
target:nil action:nil];
}
else
{
viewController.navigationItem.backBarButtonItem.title = text;
}
}
在某些情况下，导航项可能已经存在，在其他情况下需要创建它。这在不影响导航项标题的情况下解释了这两种情况。它允许你通过简单地传入@""来删除标题。
// add left bar button item
try this code:
- (void)viewDidLoad
{
[super viewDidLoad];
UIImage* image_back = [UIImage imageNamed:@"your_leftarrowImage.png"];
CGRect backframe = CGRectMake(250, 9, 15,21);
UIButton *backbutton = [[UIButton alloc] initWithFrame:backframe];
[backbutton setBackgroundImage:image_back forState:UIControlStateNormal];
[backbutton addTarget:self action:@selector(Btn_back:)
forControlEvents:UIControlEventTouchUpInside];
[backbutton setShowsTouchWhenHighlighted:YES];
UIBarButtonItem *backbarbutton =[[UIBarButtonItem alloc] initWithCustomView:backbutton];
self.navigationItem.leftBarButtonItem=backbarbutton;
[backbutton release];
}
-(IBAction)Btn_back:(id)sender
{
[self.navigationController popViewControllerAnimated:YES];
}
你可以在viewWillDisappear上将当前ViewController的标题改为@""，当它即将再次显示时，将标题重新设置为之前的标题。
-(void) viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.title = @"Previous Title";
}
-(void) viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
self.title = @"";
}
