在第一篇Car的方法中加入一个类方法：

+ (NSString *) motto {
   return(@"Ford Prefects are Mostly Harmless"); }

 

#import 
     
       #import "Car.h" //统一定义颜色和button风格 #define COOKBOOK_PURPLE_COLOR    [UIColor colorWithRed:0.20392f green:0.19607f blue:0.61176f alpha:1.0f] #define BARBUTTON(TITLE, SELECTOR)     [[[UIBarButtonItem alloc] initWithTitle:TITLE style:UIBarButtonItemStylePlain target:self action:SELECTOR] autorelease] //定义TestBedViewController控制器 @interface TestBedViewController : UIViewController @end //实现控制器 @implementation TestBedViewController //定义函数 - (void) action: (id) sender {
   // Calling a class method     NSLog(@"%@", [Car motto]);//调用类函数 } - (void) viewDidLoad {
       self.navigationController.navigationBar.tintColor = COOKBOOK_PURPLE_COLOR;     self.navigationItem.rightBarButtonItem = BARBUTTON(@"Action", @selector(action:));//设定右边导航栏的按钮的标题和事件 //此处@selector表示选择器 } @end