以编程方式将UIButtonBarItem添加到UINavigationBar

Question

我正在尝试以编程方式将UIButtonBarItem添加到UINavigationBar。我有这个类Topbar，在我的一些ViewControllers上导入，然后通过以下方式调用：[self.view addSubview:[Topbar insertTopbar]];

#import "Topbar.h"

@implementation Topbar

+(UINavigationBar*)insertTopbar
{
    UINavigationBar *navBar = [ [UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];

    UINavigationItem *navTitle = [UINavigationItem alloc];
    navTitle.title = @"MyApp";

    UINavigationItem *navAdd = [UINavigationItem alloc];
    navAdd.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem: UIBarButtonSystemItemAdd target:self action:@selector(addFood)];

    [navBar setItems:@[navAdd, navTitle] animated:false];
    return navBar;
}

@end

但是当我尝试使用navBar setItems:@[navAdd, navTitle]设置项目时，它会广告＆＃34;返回＆＃34; - 按钮

如果我然后遗漏navTitle所以它显示为navBar setItems:@[navAdd]，那么＆＃34; +＆＃34; -sign会突然出现。好像是＆＃34; navTitle＆＃34;推进第一项。

Answer 1

尝试以下方法，做了一些微调，现在对我来说工作正常！ ：）

-(UINavigationBar*)insertTopbar
{
UINavigationBar *navBar = [ [UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
UINavigationItem *navAdd = [UINavigationItem alloc];
navAdd.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem: UIBarButtonSystemItemAdd target:self action:@selector(addFood)];
[navBar pushNavigationItem:navAdd animated:YES];
navBar.topItem.title = @"MyApp";
return navBar;
}