我们可以禁用leftBarButtonItem的导航控制器,它是iPhone中视图控制器的后退按钮吗？

Question

我想禁用导航控制器的默认后退按钮

self.navigationItem.rightBarButtonItem.enabled = NO; 
// Below code does not work since leftBarButtonItem is always nil.
self.navigationItem.leftBarButtonItem.enabled = NO;

我已经手动显示如下,但有没有任何属性禁用默认后退按钮只有一行？

backButton = [[UIButton alloc] initWithFrame:CGRectMake(5, 5, 100, 30)];
[backButton setBackgroundImage:[UIImage imageNamed:@"backbutton_100.png"] forState:UIControlStateNormal];
[backButton addTarget:self  action:@selector(backAction:)  forControlEvents:UIControlEventTouchUpInside];
[backButton setTitle:@"  All Customers" forState:UIControlStateNormal];
backButton.titleLabel.font = [UIFont boldSystemFontOfSize:12];
[buttonView addSubview:backButton];

UIBarButtonItem* leftButton = [[UIBarButtonItem alloc] initWithCustomView:buttonView];
self.navigationItem.leftBarButtonItem = leftButton;
[leftButton release];

// Now it is working.
self.navigationItem.leftBarButtonItem.enabled = NO;

Answer 1

它很容易.....只是试试这个

self.navigationController.navigationBar.userInteractionEnabled = NO;   //for  disabling 

self.navigationController.navigationBar.userInteractionEnabled = YES; //for again enabling

Answer 2

使用"hidesBackButton = YES"真的不是一个优雅的解决方案,因为它隐藏了不是我们想要的按钮.一个可接受的解决方法是将UILabel添加到后窗按钮上方的窗口,至少禁用按钮上的触摸.

将此方法添加到AppDelegate类:

- (void) disableLeftBarButtonItemOnNavbar:(BOOL)disable
{
    static UILabel *l = nil;

    if (disable) {
        if (l != nil)
            return;
        l = [[UILabel alloc] initWithFrame:CGRectMake(0, 20, 160, 44)];
        l.backgroundColor = [UIColor clearColor];
        l.userInteractionEnabled = YES;
        [self.window addSubview:l];
    }
    else {
        if (l == nil)
            return;
        [l removeFromSuperview];
        [l release];
        l = nil;
    }
}

您可以从任何视图控制器中调用它来禁用:

MyAppDelegate *appDeleg = (MyAppDelegate *) [[UIApplication sharedApplication] delegate];
[appDeleg disableLeftBarButtonItemOnNavbar:YES];

启用:

MyAppDelegate *appDeleg = (MyAppDelegate *) [[UIApplication sharedApplication] delegate];
[appDeleg disableLeftBarButtonItemOnNavbar:NO];