Positioning UITabBar at the top

问题

I'm a beginner in iOS development. My question is: is it possible to position UITabBar at the top and how? I can't position my UITabBar at the top of the view.

回答1:

Is it possible? Sure, but it violates the human interface guidelines.

Screenshots:

Code:

TabController.h:

#import <UIKit/UIKit.h>

@interface TabController : UITabBarController <UITabBarControllerDelegate>

@end

TabController.m:

#import "TabController.h"

@interface TabController ()

@end

@implementation TabController

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.delegate = self;
}

- (void)viewWillLayoutSubviews
{
    [super viewWillLayoutSubviews];

    [self.tabBar invalidateIntrinsicContentSize];

    CGFloat tabSize = 44.0;

    UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;

    if (UIInterfaceOrientationIsLandscape(orientation))
    {
        tabSize = 32.0;
    }

    CGRect tabFrame = self.tabBar.frame;

    tabFrame.size.height = tabSize;

    tabFrame.origin.y = self.view.frame.origin.y;

    self.tabBar.frame = tabFrame;

    // Set the translucent property to NO then back to YES to
    // force the UITabBar to reblur, otherwise part of the
    // new frame will be completely transparent if we rotate
    // from a landscape orientation to a portrait orientation.

    self.tabBar.translucent = NO;
    self.tabBar.translucent = YES;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

@end

回答2:

Swift3: I achieve this by creating a custom class for UITabBarController:

class CustomTabBarController: UITabBarController {

   @IBOutlet weak var financialTabBar: UITabBar!

    override func viewDidLoad() {
        super.viewDidLoad()
        // I've added this line to viewDidLoad
        UIApplication.shared.statusBarFrame.size.height
        financialTabBar.frame = CGRect(x: 0, y:  financialTabBar.frame.size.height, width: financialTabBar.frame.size.width, height: financialTabBar.frame.size.height)
    }

Don't forget to set your Custom Class to TabBarController

The result would be like this:

回答3:

Here is a working swift 3 example of aviatorken89's code.

First create a new file.
Select source cocoa touch class.
Designate subclass of: UITabBarController
Name the class "CustomTabBarController" or whatever you'd like.

Add the following code to the class.

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    var tabFrame:CGRect = self.tabBar.frame
    tabFrame.origin.y = self.view.frame.origin.y
    self.tabBar.frame = tabFrame
}

If you are using storyboard make sure to change the tab bar class to your custom class via the "Identity inspector".

回答4:

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()

    tabBar.frame = CGRect(x: 0, y: 0, width: tabBar.frame.size.width, height: tabBar.frame.size.height)
}

UPDATE IOS 11 ISSUE

the code above doesnt work on ios 11. so here is workaround that i found.

override func viewDidLayoutSubviews() {
    tabBar.frame = CGRect(x: 0, y: 0, width: tabBar.frame.size.width, height: tabBar.frame.size.height)

    super.viewDidLayoutSubviews()
}

回答5:

subviews of TabbarController hide back of Tabbar . so for fix use this code :

class CustomTabBarController: UITabBarController ,UITabBarControllerDelegate{

    override func viewDidLayoutSubviews() {
        tabBar.frame = CGRect(x: 0, y: 0, width: tabBar.frame.size.width, height: tabBar.frame.size.height)
        super.viewDidLayoutSubviews()
        delegate = self
        selectedViewController?.view.frame.origin = CGPoint(x: 0, y: tabBar.frame.size.height)
    }

    func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
          selectedViewController?.view.frame.origin = CGPoint(x: 0, y: tabBar.frame.size.height)
    }

}

回答6:

You can create a custom tab bar by making it yourself, but apple highly discourages mimicking a system control for a function it was not originally intended to do.

Once again, I discourage you to do so, because it violates the consistency of your app and system apps. But since I'm at it, here we go:

For a custom tab bar, you need to create a view that holds multiple buttons. You also need a container view below the UITabBar (because you want the UITabBar to be at the top). When a button is pressed, you change the UIViewController inside the container.
Its quite simple, but of course, its strongly not recommended.

回答7:

If you want something like an UITabBar on top then how about you create a custom UIView and add any number of UIButtons in it. Then link some ViewControllers with each button through Segue. Done!

You don't need to customise the UITabBar. As aviatorken89 said earlier, it is against the human interface guideline.

来源：https://stackoverflow.com/questions/29579992/positioning-uitabbar-at-the-top

标签

ios

objective-c

swift

uitabbar