整个自定义TabBarController实现自主风格

      要自定义UITabBarController，首先我们必须了解UITabBarController结构与其各个相关类的关系（TabBarController、TabBar、TabButton及ViewController）。其中，TabButton是一个双态的Button（选中和未选中），行为和CheckBox、RadioButton类似。TabBar是TabButton的容器，负责TabButton的排布和互斥，保证同时只有一个Button为选中态。TabBarController包含了TabBar，并管理这一个ViewController的栈，在TabBar上的按钮点击时对栈上的ViewController位置进行相应的调整，从而保持TabBar和ViewController栈之间的一致性。

      熟悉了基本结构后，一般有以下常见的方案来完整自定义TabBarController。
方案一：替换部分现有的实现
      目标是替换掉系统的部分控件，可通过隐藏TabBar的方式来实现。只要做到隐藏原有的TabBar后，不要忘了在新定制的TabBar的当前选中按钮变化时通过UITabBarController的setSelectedIndex接口设置ViewController栈的当前ViewController即可。 

View Code

 1 #import <UIKit/UIKit.h>

 2 @interface CustomTabBar : UITabBarController {

 3 NSMutableArray *buttons;

 4 int currentSelectedIndex;

 5 UIImageView *slideBg;

 6 }

 7 

 8 @property (nonatomic,assign) int currentSelectedIndex;

 9 @property (nonatomic,retain) NSMutableArray *buttons;

10 

11 - (void)hideRealTabBar;

12 - (void)customTabBar;

13 - (void)selectedTab:(UIButton *)button;

14 

15 @end

View Code

 1 #import "CustomTabBar.h"

 2 

 3 @implementation CustomTabBar

 4 

 5 @synthesize currentSelectedIndex;

 6 @synthesize buttons;

 7 

 8 - (void)viewDidAppear:(BOOL)animated{

 9 slideBg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"bottomfocus.png"]];

10 [self hideRealTabBar];

11 [self customTabBar];

12 }

13 

14 - (void)hideRealTabBar{

15 for(UIView *view in self.view.subviews){

16 if([view isKindOfClass:[UITabBar class]]){

17 view.hidden = YES;

18 break;

19 }

20 }

21 }

22 

23 - (void)customTabBar{

24 UIImageView *imgView = [[UIImageView alloc] initWithImage: [UIImage imageNamed:@"tabbg2.png"]];

25 imgView.frame = CGRectMake(0, 425, imgView.image.size.width, imgView.image.size.height);

26 [self.view addSubview:imgView];

27 slideBg.frame = CGRectMake(-30, self.tabBar.frame.origin.y, slideBg.image.size.width, slideBg.image.size.height);

28 

29 //创建按钮

30 int viewCount = self.viewControllers.count > 5 ? 5 : self.viewControllers.count;

31 self.buttons = [NSMutableArray arrayWithCapacity:viewCount];

32 double _width = 320 / viewCount;

33 double _height = self.tabBar.frame.size.height;

34 for (int i = 0; i < viewCount; i++) {

35 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];

36 btn.frame = CGRectMake(i*_width,self.tabBar.frame.origin.y, _width, _height);

37 [btn addTarget:self action:@selector(selectedTab:) forControlEvents:UIControlEventTouchUpInside];

38 btn.tag = i;

39 [self.buttons addObject:btn];

40 [self.view addSubview:btn];

41 [btn release];

42 }

43 [self.view addSubview:slideBg];

44 UIImageView *imgFront = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"tabitem.png"]];

45 imgFront.frame = imgView.frame;

46 [self.view addSubview:imgFront];

47 [imgFront release];

48 [imgView release];

49 [self selectedTab:[self.buttons objectAtIndex:0]];

50 

51 }

52 

53 - (void)selectedTab:(UIButton *)button{

54 if (self.currentSelectedIndex == button.tag) {

55 

56 }

57 self.currentSelectedIndex = button.tag;

58 self.selectedIndex = self.currentSelectedIndex;

59 [self performSelector:@selector(slideTabBg:) withObject:button];

60 }

61 

62 - (void)slideTabBg:(UIButton *)btn{

63 [UIView beginAnimations:nil context:nil]; 

64 [UIView setAnimationDuration:0.20]; 

65 [UIView setAnimationDelegate:self];

66 slideBg.frame = CGRectMake(btn.frame.origin.x - 30, btn.frame.origin.y, slideBg.image.size.width, slideBg.image.size.height);

67 [UIView commitAnimations];

68 }

69 

70 - (void) dealloc{

71 [slideBg release];

72 [buttons release];

73 [super dealloc];

74 }

75 @end

使用这个自定义类来创建UITabBarController

View Code

 1 // Override point for customization after application launch.

 2 FirstViewController *mainViewController = [[FirstViewController alloc] init];

 3 SecondViewController *searchViewController = [[SecondViewController alloc]init];

 4 ThirdViewController *myselfViewController = [[ThirdViewController alloc]init];

 5 ForthViewController *settingViewController = [[ForthViewController alloc]init];

 6 

 7 //隐藏tabbar所留下的黑边（试着注释后你会知道这个的作用）

 8 mainViewController.hidesBottomBarWhenPushed = true;

 9 searchViewController.hidesBottomBarWhenPushed = true;

10 myselfViewController.hidesBottomBarWhenPushed = true;

11 settingViewController.hidesBottomBarWhenPushed = true;

12 

13 mainViewController.title = @"首页";

14 searchViewController.title = @"搜索";

15 myselfViewController.title = @"我";

16 settingViewController.title = @"设置";

17 

18 //创建导航

19 UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:mainViewController ];

20 UINavigationController *nav1 = [[ UINavigationController alloc] initWithRootViewController:searchViewController];

21 UINavigationController *nav2 = [[UINavigationController alloc] initWithRootViewController:myselfViewController];

22 UINavigationController *nav3 = [[UINavigationController alloc]initWithRootViewController:settingViewController]; 

23 //创建数组

24 NSMutableArray *controllers = [[NSMutableArray alloc]init];

25 [controllers addObject:nav];

26 [controllers addObject:nav1];

27 [controllers addObject:nav2];

28 [controllers addObject:nav3];

29 

30 //创建tabbar

31 tabBarController = [[ CustomTabBar alloc] init];

32 tabBarController.viewControllers = controllers;

33 tabBarController.selectedIndex = 0;

34 

35 //显示

36 [self.window addSubview:tabBarController.view];

37 [self.window makeKeyAndVisible];