cocoa下的多线程实践

线程相关的类:NSThread ,NSOperation ,NSOperationQueue

在实际应用中可以分为2种方式：
1、使用NSThread
2、使用NSOperation,NSOperationQueue

前者，和过往window下的线程学习类似；后者，是mac以队列的方式来新建线程。

针对前者，写部分代码：

- (void)threadFunc:(id)info
{
    NSLog(@"%@ ,run thread" ,info);
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    [NSThread detachNewThreadSelecor:@selector(threadFunc:) toTarget:self withObject:nil];
}

针对后者，也写些代码：

@interface PageLoadOperation : NSOperation

@property (retain) NSURL *targetURL;

- (id)initWithUrl:(NSURL *)url;

@end

@implementation PageLoadOperation

@synthesize targetURL;

- (id)init
{
    self = [super init];
    if (self)
    {
        self->targetURL = nil;
    }
    
    return self;
}

- (id)initWithUrl:(NSURL *)url
{
    self = [self init];
    if (self)
    {
        self->targetURL = url ? [url retain] : nil;
    }
    
    return self;
}

- (void)dealloc
{    
    if (self.targetURL)
        [self->targetURL release];
    [super dealloc];
}

- (void)main
{
    NSLog(@"main run");
    
    if (self.targetURL == nil)
        return;
    
    NSError *error = nil;
    NSData *data = [[[NSData alloc] initWithContentsOfURL:self.targetURL options:NSDataReadingMappedAlways error:&error] autorelease];
    
    if (error)
        NSLog(@"error infomation : %@" ,erro);
    else if (data)
    {
        NSLog(@"%@" ,data);
    }
}

@end

调用有两种：
1、直接调用

    PageLoadOperation *p = [[PageLoadOperation alloc] initWithUrl:[NSURL URLWithString:@"http://www.sohu.com"]];
    //p.targetURL = [NSURL URLWithString:@"http://www.baidu.com"];
    [p start];
    [p release];

2、使用NSOperationQueue

NSOperationQueue *_queue = [[NSOperationQueue alloc] init];

PageLoadOperation *plo = [[PageLoadOperation alloc] initWithUrl:[NSURL URLWithString:url]];
plo.delegate = self;
[_queue addOperation:plo];
        
[plo release];

[_queue release];