案例描写叙述：实现下图所看到的的效果。被时间函数什么的搞乱了，就仅仅搭了一个框架，详细实现的计时功能等整好了一起上传~~~ （看看这引入的n个头文件，俺也是醉了~）

效果图：

详细代码：

#import "JRTabBarController.h"

#import "MiaoBiaoNavigationController.h"

#import "MiaoBiaoViewController.h"

#import "JSQNavigationController.h"

#import "JSQViewController.h"

#import "NaoZhongViewController.h"

#import "NZNavigationController.h"

#import "SJSZNavigationController.h"

#import "SJSZViewController.h"

#define kLeftSpace 30   //左边距

#define kRightSpace 30  //右边距

#define kMiddleSpace 40 //中间空白距

#define kW self.view.frame.size.width   

#define kH self.view.frame.size.height

@interface JRTabBarController ()

//点击button切换图片

@property (nonatomic,strong)NSMutableArray * buttonArray;

@end

@implementation JRTabBarController

#pragma mark - 懒载入

- (NSMutableArray *)buttonArray

{

    if (_buttonArray==nil)

    {

        _buttonArray=[NSMutableArrayarray];

    }

    return _buttonArray;

}

- (void)viewDidLoad {

    [superviewDidLoad];

    self.view.backgroundColor=[UIColorwhiteColor];

    //1.载入控制器

    [self_loadVC];

    //2.自己定义TabBar

    [self_makeTabBar];

}

#pragma mark - 载入控制器

- (void) _loadVC

{

    //创建视图控制器

    //世界时间

    SJSZViewController * sjVC=[[SJSZViewControlleralloc]init];

    SJSZNavigationController * vc1=[[SJSZNavigationControlleralloc]initWithRootViewController:sjVC];

   //闹钟

    NaoZhongViewController * nzVC=[[NaoZhongViewControlleralloc]init];

    NZNavigationController * vc2=[[NZNavigationControlleralloc]initWithRootViewController:nzVC];

   //秒表

    MiaoBiaoViewController * mbVC=[[MiaoBiaoViewControlleralloc]init];

//    mbVC.view.backgroundColor=[UIColor redColor];

    MiaoBiaoNavigationController * vc3=[[MiaoBiaoNavigationControlleralloc]initWithRootViewController:mbVC];

    //计时器

    JSQViewController * jsqVC=[[JSQViewControlleralloc]init];

    JSQNavigationController * vc4=[[JSQNavigationControlleralloc]initWithRootViewController:jsqVC];

   self.viewControllers=@[vc1,vc2,vc3,vc4];

    self.selectedViewController=vc3;

}

#pragma mark - 自己定义TabBar

- (void) _makeTabBar

{

    //1.定制TabBar

   UIView * bgView=[[UIViewalloc] initWithFrame:CGRectMake(0,kH-49,kW,49)];

    bgView.backgroundColor=[UIColorwhiteColor];

    [self.viewaddSubview:bgView];

    //2.定制button

    CGFloat space=(kW-kLeftSpace-kRightSpace-3*kMiddleSpace)/4; //每一个小button的宽度

   for (int i=0; i<4; i++)

    {

       UITabBarButton * button=[[UITabBarButtonalloc]initWithFrame:CGRectMake(kLeftSpace+i*space+i*kMiddleSpace,0, space, 49)];

        button.backgroundColor=[UIColorwhiteColor];

        button.tag=i;

       NSString * imageName=[NSStringstringWithFormat:@"%d",i+1];

        [button setImage:[UIImageimageNamed:imageName] forState:UIControlStateNormal];

       if (i==2)

        {

           NSString * imageName=[NSStringstringWithFormat:@"0%d",i+1];

            [button setImage:[UIImageimageNamed:imageName] forState:UIControlStateNormal];

        }

        [button addTarget:selfaction:@selector(changeImage:)forControlEvents:UIControlEventTouchUpInside];

        button.delegateMe=self;

        [self.buttonArrayaddObject:button];

        [bgViewaddSubview:button];

    }

}

- (void) changeImage:(UITabBarButton *) button

{

   for (int i=0; i<4; i++)

    {

       if (i!=button.tag)

        {

           NSString * imageName=[NSStringstringWithFormat:@"%d",i+1];

           UIButton *butt=self.buttonArray[i];

            [butt setImage:[UIImageimageNamed:imageName] forState:UIControlStateNormal];

        }

    }

    [button.delegateMechangePage:button.tag];

   NSString * imageName=[NSStringstringWithFormat:@"0%d",(int)(button.tag+1)];

    [button setImage:[UIImageimageNamed:imageName] forState:UIControlStateNormal];

}

- (void)changePage:(NSInteger)index

{

    [UIViewbeginAnimations:nilcontext:nil];

    [UIViewcommitAnimations];

    self.selectedIndex=index;

}

@end

#import "MiaoBiaoViewController.h"

#define kW self.view.frame.size.width

#define kH self.view.frame.size.height

@interface MiaoBiaoViewController ()

{

   NSDateFormatter *fomatter;

    NSInvocationOperation *operation1;

    NSInvocationOperation *operation2;

}

//@property (nonatomic,weak) 

@end

@implementation MiaoBiaoViewController

- (void)viewDidLoad {

    [superviewDidLoad];

   self.title=@"秒表";

    //小时钟

   UILabel * conLabel=[[UILabelalloc]initWithFrame:CGRectMake(267,85, 110, 50)];

//    conLabel.backgroundColor=[UIColor redColor];

    conLabel.text=@"00:00.00";

    conLabel.font=[UIFontfontWithName:nilsize:25];

    [self.viewaddSubview:conLabel];

   //秒表

    UILabel * ctLabel=[[UILabelalloc]initWithFrame:CGRectMake(0,160,kW,150)];

//    ctLabel.backgroundColor=[UIColor redColor];

    ctLabel.text=@"00:00.00";

    ctLabel.textAlignment=NSTextAlignmentCenter;

    ctLabel.font=[UIFontfontWithName:nilsize:75];

    [self.viewaddSubview:ctLabel];

    //下方视图

    UIView * bView=[[UIViewalloc]initWithFrame:CGRectMake(0,350,kW,300)];

    bView.backgroundColor=[UIColorcolorWithRed:0.1green:0.1blue:0.1alpha:0.1];

    [self.viewaddSubview:bView];

    //開始停止button

   UIButton * ssButton=[[UIButtonalloc]initWithFrame:CGRectMake((kW-200)/3,30, 100, 100)];

    ssButton.backgroundColor=[UIColorwhiteColor];

    ssButton.layer.cornerRadius=50;

    [ssButton setTitle:@"開始"forState:UIControlStateNormal];

    [ssButton setTitle:@"停止"forState:UIControlStateSelected];

    [ssButton setTitleColor:[UIColorredColor] forState:UIControlStateNormal];

    [ssButton setTitleColor:[UIColorgrayColor] forState:UIControlStateSelected];

    ssButton.tag=1;

    [ssButton addTarget:selfaction:@selector(StartStop:)forControlEvents:UIControlEventTouchUpInside];

    [bViewaddSubview:ssButton];

    //计次button

   UIButton * jcButton=[[UIButtonalloc]initWithFrame:CGRectMake(((kW-200)/3)*2+100,30, 100, 100)];

    jcButton.backgroundColor=[UIColorwhiteColor];

    jcButton.layer.cornerRadius=50;

    [jcButton setTitle:@"计次"forState:UIControlStateNormal];

    [jcButton setTitleColor:[UIColorblackColor] forState:UIControlStateNormal];

    [jcButton addTarget:selfaction:@selector(CountNum)forControlEvents:UIControlEventTouchUpInside];

    [bViewaddSubview:jcButton];

}

- (void)StartStop:(UIButton *) button

{

    button.selected = !button.selected;

   NSLog(@"%i", button.selected);

    NSLog(@"asdasdasd");

}

- (void)CountNum

{

    NSLog(@"////////");

}

@end

PS：做一个小项目是最能考验一个人的综合水平，so，自觉水平太low了~ ~ ~   一定要好好补补课啊！。。（ 心碎难补中~）