ObjecticeC之方法、消息和选择器

　　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 <UIKit/UIKit.h>
#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