多线程:一个简单的售票系统

下面介绍一个运用多线程的简单售票系统，代码是在上一篇文章的基础上进行操作的。

首先，创建一个继承UIViewController的类YueTwoViewController，然后在YueAppDelegate.m中添加代码：

- (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];
    
    YueViewController *viewController = [[YueViewController alloc]initWithNibName:nil bundle:nil];
    YueTwoViewController *pTwoVC = [[YueTwoViewController alloc]initWithNibName:nil bundle:nil];
    
    UITabBarController *pTabbarVC = [[UITabBarController alloc]init];
    pTabbarVC.viewControllers = [NSArray arrayWithObjects:viewController,pTwoVC,nil];
    //设置窗口的根视图
    self.window.rootViewController = pTabbarVC;
    [pTabbarVC release];
    [viewController release];
    [pTwoVC release];
    [pThirdVC release];
    
    [self.window makeKeyAndVisible];
    return YES;
}

在YueTwoViewController.xib文件中拖拽控件，并将它们关联到YueTwoViewController.h中

在YueTwoViewController.m中进行方法的实现和操作

#import "YueTwoViewController.h"

@interface YueTwoViewController ()

@end

@implementation YueTwoViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.tabBarItem.title = @"Thread-2";
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    //设置剩余票的数量
    _lefttickets = 100;
    //设置卖出的票数
    _saletickets = 0;
    _ticketsCondition = [[NSCondition alloc]init];
    
    //创建一个Button，并对其进行相应的操作，关联一个方法
    UIButton *pBtn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [pBtn setFrame:CGRectMake(100, 360, 80, 40)];
    [pBtn setTitle:@"Start" forState:UIControlStateNormal];
    [pBtn addTarget:self action:@selector(threadStart:)forControlEvents:UIControlEventTouchUpInside];
    //添加到当前视图上
    [self.view addSubview:pBtn];
    
}

- (void)threadStart:(id)sender
{
    //创建第一个子线程
    _firstThread = [[NSThread alloc]initWithTarget:self selector:@selector(run:) object:nil];
    //设置子线程的名字
    [_firstThread setName:@"Thread-One"];
    //开始子线程
    [_firstThread start];
    
    _secondThread = [[NSThread alloc]initWithTarget:self selector:@selector(run:) object:nil];
    [_secondThread setName:@"Thread_Two"];
    [_secondThread start];
    
    _thirdThread = [[NSThread alloc]initWithTarget:self selector:@selector(run:) object:nil];
    [_thirdThread setName:@"Thread_Three"];
    [_thirdThread start];
    
}

- (void)run:(id)sender
{
    while (TRUE)
    {
        [_ticketsCondition lock];
        if (_lefttickets > 0)
        {
            [NSThread sleepForTimeInterval:0.1];
            _lefttickets--;
            _saletickets = 100 - _lefttickets;
            NSString *pSta = [[NSThread currentThread]name];
            NSLog(@"售出票数:%i,剩余票数:%i,当前票数:%@",_saletickets,_lefttickets,pSta);
            
        }
        else if (_lefttickets == 0)
        {
            NSLog(@"票已售完");
            break;
        }
        [self performSelectorOnMainThread:@selector(updateMyView:) withObject:[[NSThread currentThread]name] waitUntilDone:YES];
        [_ticketsCondition unlock];
    }
}

- (void)updateMyView:(id)sender
{
    self.labelleft.text = [NSString stringWithFormat:@"%i",_lefttickets];
    self.labelsale.text = [NSString stringWithFormat:@"%i",_saletickets];
    self.currentThread.text = (NSString *)sender;
    
    if (_lefttickets == 0)
    {
        UIAlertView *pAlertView = [[UIAlertView alloc]initWithTitle:@"通知" message:@"今日票已售完" delegate:nil cancelButtonTitle:nil otherButtonTitles:@"确认", nil];
        [pAlertView show];
        [pAlertView release];
    }
    
    
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)dealloc {
    [_ticketsCondition release];
    [_labelsale release];
    [_labelleft release];
    [_currentThread release];
    [super dealloc];
}
@end

运行后，就可以观察子线程的顺行情况了。