用代码创建UITabBarController

文章目的

如何用纯代码的方式创建UITabBarController

方法

1. 首先开启XCode并建立一个Empty Application

2. 加入一个Objective-C Class并继承自UIViewController，取名为FirstViewController

3. 重复一次上面动作，并取名为SecondViewController

4. 之后可在工程中看到此图

5. 开启AppDelegate.h，并加入如下代码

#import <UIKit/UIKit.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate>
{
    UITabBarController* tabBarViewController;
}

@property (strong, nonatomic) UIWindow *window;

@end

6. 开启AppDelegate.m，并加入如下代码

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    
    tabBarViewController = [[UITabBarController alloc]init];
    [self.window setRootViewController:tabBarViewController];
    
    FirstViewController* first = [[FirstViewController alloc]init];
    SecondViewController* second = [[SecondViewController alloc]init];
    tabBarViewController.viewControllers = [NSArray arrayWithObjects:first, second, nil];
    [first release];
    [second release];
}

    tabBarViewController = [[UITabBarController alloc]init];
    [self.window setRootViewController:tabBarViewController];

第一行代码为初始一个UITabBarController

第二行为将tabBarViewController设定为window的root view controller(根视图控制器)

tabBarViewController.viewControllers = [NSArray arrayWithObjects:first, second, nil];

接下来利用UITabBarController的viewControllers属性，设定First及Second两个控制器。

7.用代码修改TabBar与TabBarItem

UITabBar *tabBar = tabBarViewController.tabBar;
UITabBarItem *tabBarItem1 = [tabBar.items objectAtIndex:0];
UITabBarItem *tabBarItem2 = [tabBar.items objectAtIndex:1];

UITabBarController提供一个tabBar属性，我们可以透过这个属性取得UITabBar

并在UITabBar的items属性取得所有的UITabBarItem

tabBarItem1.title = @"Home";
tabBarItem2.title = @"Maps";

透过UITabBarItem的title属性,可以设定tab bar item上显示的文字

[tabBarItem1 setFinishedSelectedImage:[UIImage imageNamed:@"home_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"home.png"]];
[tabBarItem2 setFinishedSelectedImage:[UIImage imageNamed:@"maps_selected.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"maps.png"]];

-(void)set<wbr>Finished<wbr>Selected<wbr>Image:(<code><a target="_blank" href="file:///Applications/Xcode.app/Contents/PlugIns/IDEQuickHelp.ideplugin/Contents/Resources/documentation/UIKit/Reference/UIImage_Class/Reference/Reference.html#//apple_ref/doc/c_ref/UIImage" title="" data-line="" data-column="" style="color: rgb(0, 51, 102); text-decoration: none; ">UI<wbr>Image</wbr></a> *</code>)<code>selected<wbr>Image</wbr></code> with<wbr>Finished<wbr>Unselected<wbr>Image:(<code><a target="_blank" href="file:///Applications/Xcode.app/Contents/PlugIns/IDEQuickHelp.ideplugin/Contents/Resources/documentation/UIKit/Reference/UIImage_Class/Reference/Reference.html#//apple_ref/doc/c_ref/UIImage" title="" data-line="" data-column="" style="color: rgb(0, 51, 102); text-decoration: none; ">UI<wbr>Image</wbr></a> *</code>)<code>unselected<wbr>Image</wbr></code></wbr></wbr></wbr></wbr></wbr></wbr>

这是UITabBarItem提供的方法，可以设定上面所显示的图片,selectedImage是只目前选择并显示的TabBatItem显示的图片

unselectedImage则是平常未选中时显示的图片

UIImage* tabBarBackground = [UIImage imageNamed:@"tabbar.png"];
[[UITabBar appearance] setBackgroundImage:tabBarBackground];

这段代码可以修改UITabBar显示的背景图

[[UITabBar appearance] setSelectionIndicatorImage:[UIImage imageNamed:@"tabbar_selected.png"]];

这可以设定选中的UITabBarItem后面的图

UIColor *titleHighlightedColor = [UIColor colorWithRed:153/255.0 green:192/255.0 blue:48/255.0 alpha:1.0];
[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                                       titleHighlightedColor, UITextAttributeTextColor,
                                                       nil] forState:UIControlStateHighlighted];

-(void)set<wbr>Title<wbr>Text<wbr>Attributes:(<code>NS<wbr>Dictionary *</wbr></code>)<code>attributes</code> for<wbr>State:(<code>UI<wbr>Control<wbr>State</wbr></wbr></code>)<code>state</code></wbr></wbr></wbr></wbr>

这个方法可以设定显示文字的属性，在这段代码中，是设定为显示文字的颜色

范例下载

其他参考

poolo的tabbar超过五个,如何修改more