Moving UITabBarItem Image down?

问题

Normally on each tab of a UITabBar you have a small image and a title naming the tab. The image is positioned/centred towards the top of the tab to accommodate the title underneath. My question is: if you want to have a tabBar with just an image and no title is there a way to move the image down so it centers better within the tab?

I am using (see below) currently:

[tabBarItem setFinishedSelectedImage:tabSelected withFinishedUnselectedImage:tabUnselected];

but would prefer to use to larger image with no title, at the moment if I make the image bigger than about 70pixels@2x it starts edging off the top of the UITabBar whilst leaving a lot of unused space at the bottom.

回答1:

Try adjusting tabBarItem's imageInsets (for moving the icon image) and setting the controllers title to nil (so no title is displayed). Put something like this to -init or -viewDidLoad method in view controller:

Objective-C

self.tabBarItem.imageInsets = UIEdgeInsetsMake(6, 0, -6, 0);
self.title = nil;

Swift

self.tabBarItem.imageInsets = UIEdgeInsets(top: 6, left: 0, bottom: -6, right: 0)
self.title = nil

UITabBarItem is a subclass of UIBarItem which has UIEdgeInsets imageInsets property. Play a little with the insets until it looks good (depending on your tabbar icon images)

回答2:

You can do it via storyboard too. Select your tabbaritem, go to size inspector and assign the appropriate insets.

*Demonstrated on Xcode, Version 7.3.1 (7D1014)

回答3:

Make a subclass of UITabBarController, and in its viewDidLoad:

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self.viewControllers enumerateObjectsUsingBlock:^(UIViewController *vc, NSUInteger idx, BOOL *stop) {
        vc.tabBarItem.title = nil;
        vc.tabBarItem.imageInsets = UIEdgeInsetsMake(5, 0, -5, 0);
    }];
}

Swift 3:

for vc in self.viewControllers! {
    vc.tabBarItem.title = nil
    vc.tabBarItem.imageInsets = UIEdgeInsetsMake(5, 0, -5, 0)
}

回答4:

If you're using Xamarin, this works:

screen.TabBarItem.ImageInsets = new UIEdgeInsets(5, 0, -5, 0);
screen.TabBarItem.Title = "";

回答5:

This worked for me

Swift 4

let array = tabBarController?.customizableViewControllers
for controller in array! {
    controller.tabBarItem.imageInsets = UIEdgeInsetsMake(5, 0, -5, 0)
}

回答6:

SWIFT 3.0

You can set image lnsets, set top,left,bottom and right according desing.

self.tabBarItem.imageInsets = UIEdgeInsets(top: 5, left: 0, bottom: 0, right: 0)

回答7:

For iOS 11 you need to override TraitCollection method apart from setting ImageInsets. Please add the method in your subclassed UITabBarController class

public override UITraitCollection TraitCollection {
 get {
  return UITraitCollection.FromHorizontalSizeClass(horizontalSizeClass: UIUserInterfaceSizeClass.Compact);
 }
}

回答8:

In Swift 4.2, UIEdgeInsetsMake is depricated, instead we should use UIEdgeInsets,

let array = tabBarController?.customizableViewControllers
    for controller in array! {
        controller.tabBarItem.imageInsets = UIEdgeInsets(top: 5, left: 0, bottom: -5, right: 0)
    }

来源：https://stackoverflow.com/questions/16285205/moving-uitabbaritem-image-down

标签

iphone

objective-c

cocoa-touch

uitabbar

uitabbaritem