线程间通信-03-GCD

//
//  ViewController.m
//  03-GCD-线程间通信
//
//  Created by mac on 16/4/21.
//  Copyright © 2016年 mac. All rights reserved.
//
#define GlobalQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
#define MainQueue dispatch_get_main_queue()

#import "ViewController.h"

@interface ViewController ()
/**
 *   oc语法中：1. 属性名不能以new开头  2. init开头的构造方法中才允许self进行赋值
 */
//@property (weak, nonatomic) IBOutlet UIImageView *newImageView;

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

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

}
/**
 *  属性不能以new开头，new有特殊含义
 */
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {

    dispatch_async(GlobalQueue, ^{

        //1. 子线程中下载图片
        NSURL *url = [NSURL URLWithString:@"http://img0.imgtn.bdimg.com/it/u=4168762024,1922499492&fm=21&gp=0.jpg"];
        NSData *data = [NSData dataWithContentsOfURL:url];
        UIImage *image = [UIImage imageWithData:data];

        NSLog(@"===%@,%@", image, [NSThread currentThread]);

        //2. 主线程中设置图片
        dispatch_async(MainQueue, ^{

            [self.buttonImage setBackgroundImage:image forState:UIControlStateNormal];
            NSLog(@"=%@,%@", image, [NSThread currentThread]);

        });
    });
}

@end