NSoperation线程通信

全局变量

@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@property (nonatomic, strong) NSOperationQueue * queue;

懒加载

- (NSOperationQueue *)queue {

    if (!_queue) {
        _queue = [[NSOperationQueue alloc] init];
    }
    return _queue;
}

事件的响应方法

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    __block UIImage * image1;

    //创建操作1
    NSBlockOperation * download1 = [NSBlockOperation blockOperationWithBlock:^{

        NSURL * url = [NSURL URLWithString:@"http://g.hiphotos.baidu.com/lvpics/w=1000/sign=82800ad878cb0a4685228f395b53f724/96dda144ad3459823cc40db00ff431adcbef8442.jpg"];

        NSData * data = [NSData dataWithContentsOfURL:url];

        image1 = [UIImage imageWithData:data];

        NSLog(@"download1- %@",[NSThread currentThread]);

    }];

    __block UIImage * image2;

    //创建操作2
    NSBlockOperation * download2 = [NSBlockOperation blockOperationWithBlock:^{

        NSURL * url = [NSURL URLWithString:@"http://f.hiphotos.baidu.com/lvpics/h=800/sign=08f9c974e21190ef1efb9fdffe1a9df7/c8177f3e6709c93dfd03176e9a3df8dcd00054b1.jpg"];

        NSData * data = [NSData dataWithContentsOfURL:url];

        image2 = [UIImage imageWithData:data];

        NSLog(@"download2- %@",[NSThread currentThread]);

}];

    //创建操作3（用于合并图片）
    NSBlockOperation * combine = [NSBlockOperation blockOperationWithBlock:^{

        //创建位图上下文
        UIGraphicsBeginImageContextWithOptions(CGSizeMake(200, 200), NO, 1);

        //设置显示的位置
        [image1 drawInRect:CGRectMake(0, 0, 200, 100)];

        [image2 drawInRect:CGRectMake(0, 100, 200, 100)];

        //获取当前图片上下文
        UIImage * image = UIGraphicsGetImageFromCurrentImageContext();

        UIGraphicsEndImageContext();

        NSLog(@"combine- %@",[NSThread currentThread]);

//返回主线程更新UI
        [[NSOperationQueue mainQueue] addOperationWithBlock:^{

            self.imageView.image = image;
            NSLog(@"main - %@",[NSThread currentThread]);

}];
    }];

    //设置操作的依赖关系
    [combine addDependency:download1];
    [combine addDependency:download2];

    //向全局队列添加操作
    [self.queue addOperations:@[download1,download2,combine] waitUntilFinished:YES];

}

巴特西

NSoperation线程通信

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