垂直对齐 UINavigationItems

Question

我已将 UINavigationBar 的高度自定义为 100px，并且我想在这个自定义栏上添加按钮。

一切都很好，除了按钮似乎无论如何都想坐在导航栏的底部。我无法让它与导航栏的中心或顶部对齐。

这是代码；首先，我在应用程序委托中创建一个导航控制器，并在右侧添加一个按钮。

// set main navigation controller
temp *tempc = [[temp alloc] initWithNibName:@"temp" bundle:nil];
self.navigationController = [[UINavigationController alloc] initWithRootViewController:tempc];

UIBarButtonItem *navItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:nil action:nil];

[tempc.navigationItem setRightBarButtonItem:navItem];
[self.window addSubview:self.navigationController.view];
[self.window makeKeyAndVisible];

然后我调整“临时”视图控制器中导航栏的大小，如下所示：

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];
    CGRect frame = CGRectMake(0.0f, 0.0f, 320.0f, 100.0f);
    [self.navigationController.navigationBar setFrame:frame];
    [self.navigationController.navigationBar setAutoresizingMask:UIViewAutoresizingFlexibleBottomMargin];
}

我还尝试向 rightBarButtonItem 添加自定义视图，但无法让添加的自定义视图完全触摸顶部。

以及此不幸尝试的代码：

// set main navigation controller
temp *tempc = [[temp alloc] initWithNibName:@"temp" bundle:nil];
self.navigationController = [[UINavigationController alloc] initWithRootViewController:tempc];

UIView *customView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 36.0f, 80.0f)];
[customView setBackgroundColor:[UIColor blueColor]];

UIButton *customButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[customButton setFrame:CGRectMake(0, 22.0f, 36.0f, 36.0f)];
[customButton setTitle:@"+" forState:UIControlStateNormal];

[customView addSubview:customButton];
UIBarButtonItem *customItem = [[UIBarButtonItem alloc] initWithCustomView:customView];

有谁知道如何在 UINavigationBar 上垂直对齐 UIBarButtonItems 吗？

Answer 1

这会将页面标题和所有按钮向上移动 20 像素：

[[UINavigationBar appearance] setTitleVerticalPositionAdjustment:-20.0 forBarMetrics:UIBarMetricsDefault];
[[UIBarButtonItem appearance] setBackgroundVerticalPositionAdjustment:-20.0 forBarMetrics:UIBarMetricsDefault];

Answer 2

如果您只有 rightBarButtonItem 而没有 left，则当前接受的 alhcr 答案（选项 1）不起作用。它还对 UINavigationBar 的子视图排序做出了假设，但这种假设并不能得到保证，并且很可能在 iOS 的未来版本中发生变化。这是自定义导航按钮框架的更好方法：

// UINavigationBar subclass

- (void)layoutSubviews {

    [super layoutSubviews];

    UINavigationItem *navigationItem = [self topItem];

    for (UIView *subview in [self subviews]) {

        if (subview == [[navigationItem rightBarButtonItem] customView]) {

            CGRect newRightButtonRect = CGRectMake(...new rect...);
            [subview setFrame:newRightButtonRect];
        }
        else if (subview == [[navigationItem backBarButtonItem] customView]) {

            CGRect newBackButtonRect = CGRectMake(...new rect...);
            [subview setFrame:newBackButtonRect];
        }
    }
}

Answer 3

选项 1：

• 创建 UINavigationBar 子类
• 在此类覆盖 - (void)layoutSubviews 中
• ，您将在 Interface Builder 中重新定位 UIBarButtonItems 将 UINavigationBar 类设置为 UINavigationBar 子类

示例：

在 UINavigationBar 的子类中：

- (void)layoutSubviews {
    int index = 0;
    for ( UIButton *button in [self subviews] ) {
        if(index == 1) {
            [button setFrame:CGRectMake(5,40,60,40)]; //leftBarButtonItem
        } else if(index == 2) {
            [button setFrame:CGRectMake(275,40,40,40)]; //rightBarButtonItem
        }
        ++index;
    }
}

视图控制器：

- (void)viewDidLoad {
...
    UIBarButtonItem *navItem1 = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:nil action:nil];
    UIBarButtonItem *navItem2 = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:nil action:nil];
    [self.navigationItem setRightBarButtonItem:navItem1];   
    [self.navigationItem setLeftBarButtonItem:navItem2];

    CGRect frame = CGRectMake(0.0f, 0.0f, 320.0f, 100.0f);
    [self.navigationController.navigationBar setFrame:frame];
...
}

选项 2（插入UIBarButtonItem 不起作用）：

UINavigationBar *navigationBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0,0,320,100)];
[self.view addSubview:navigationBar];

UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button setFrame:CGRectMake(0,25,50,50)];
[navigationBar addSubview:button];

Answer 4

我通过调整自定义按钮的图像边缘插入找到了这个问题的解决方案。我在应用程序中要求增加导航栏的高度，增加高度后会导致 rightBarButtonItem 和 leftBarButtonItem 图像未定位问题。

找到下面的代码：-

UIImage *image = [[UIImage imageNamed:@"searchbar.png"];
UIButton* searchbutton = [UIButton buttonWithType:UIButtonTypeCustom];
[searchbutton addTarget:self action:@selector(searchBar:) forControlEvents:UIControlEventTouchUpInside]; 
searchbutton.frame = CGRectMake(0,0,22, 22);
[searchbutton setImage:image forState:UIControlStateNormal];
[searchbutton setImageEdgeInsets:UIEdgeInsetsMake(-50, 0,50, 0)];
// Make BarButton Item
 UIBarButtonItem *navItem = [[UIBarButtonItem alloc] initWithCustomView:searchbutton];
self.navigationItem.rightBarButtonItem = navItem;