Implementing custom UITabBarController without private APIs

问题

After searching through several question on StackOverflow I've found out that there is only 1 major project for creating custom UITabBar called BCTabBarController. The description to it says:

There are several problems with using the standard UITabBarController including:

It is too tall, especially in landscape mode

The height doesn't match the UIToolbar

It cannot be customized without using private APIs

Nevertheless, I've found this strange project on GitHub with the tutorial here that uses standard UITabBarController in its implementation with UIButtons for each tab and it's working (strangely enough, but it does).

I was wondering, if this is wrong to create your custom UITabBarController with UIButtons instead of tabs and what would it result into? The implementation of this looks like this:

- (void)viewDidAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [self hideTabBar];
    [self addCustomElements];
}

- (void)hideTabBar
{
    for(UIView *view in self.view.subviews)
    {
        if([view isKindOfClass:[UITabBar class]])
        {
            view.hidden = YES;
            break;
        }
    }
}

-(void)addCustomElements
{
    // Initialise our two images
    UIImage *btnImage = [UIImage imageNamed:@"NavBar_01.png"];
    UIImage *btnImageSelected = [UIImage imageNamed:@"NavBar_01_s.png"];

    self.btn1 = [UIButton buttonWithType:UIButtonTypeCustom]; //Setup the button
    btn1.frame = CGRectMake(0, 430, 80, 50); // Set the frame (size and position) of the button)
    [btn1 setBackgroundImage:btnImage forState:UIControlStateNormal]; // Set the image for the normal state of the button
    [btn1 setBackgroundImage:btnImageSelected forState:UIControlStateSelected]; // Set the image for the selected state of the button
    btn1.backgroundColor = [UIColor yellowColor];
    [btn1 setTag:0]; // Assign the button a "tag" so when our "click" event is called we know which button was pressed.
    [btn1 setSelected:true]; // Set this button as selected (we will select the others to false as we only want Tab 1 to be selected initially

In my project I will be using iOS 5.1 and up and no Storyboards or XIBs. Thanks!

回答1:

Since iOS 5.0, it is no longer a problem to create your own UITabBarController using a line of UIButtons at the bottom of the screen.

In previous versions of the iOS SDK, it was a bit risky as you had to manage the forwarding of the viewWill/viewDidmethods by yourself.

Have a look at the UIViewController Class Reference, section Implementing a Container View Controller, you will find all you need there : UIViewController Class Reference

There is also a featured article explaining exactly what you need : Creating Custom Container View Controllers

Hope this will help,

来源：https://stackoverflow.com/questions/15201870/implementing-custom-uitabbarcontroller-without-private-apis