第一篇：线程间的通信

 

1.线程间的通信：在一个进程中，线程往往不是独立存在的，多个线程之间需要经常进行通信。

2.线程间通信的体现：

   一个线程传递数据给另一个线程

  在一个线程执行完特定任务后，转到另一个线程继续执行任务

3.线程间通信常用方法：

—(void)performSelectorOnMainThread:(SEL)aselector  withObject:(id)arg waitUntilDone:(BOOL)wait;

—(void)performSelector:(SEL)aselector onThread:(NSTread*)thr WithObject:(id)arg waitUntilDone:(BOOL)wait;

4.我们就用图表做示例：

5.代码如下：

#import "ViewController.h"

@interface ViewController ()

@property(nonatomic,strong)UIButton*button;

@end

 

@implementation ViewController

 

- (void)viewDidLoad {

    [super viewDidLoad];

    self.view.backgroundColor=[UIColor whiteColor];

    [self UIButton];

   

}

-(void)UIButton{

    self.button=[[UIButton alloc]initWithFrame:CGRectMake(130, 50, 100, 50)];

    self.button.backgroundColor=[UIColor blueColor];

    [self.button addTarget:self action:@selector(download) forControlEvents:UIControlEventTouchUpInside ];

    [self.view addSubview:_button];

}

-(void)download{

    //1.根据url下载图片

    //从网络下载图片

    NSURL * url = [NSURL URLWithString:@"http://img3.cache.netease.com/3g/2015/9/29/20150929110202279dd.png"];

    

    

    //把图片转化为二进制

    NSData*data = [NSData dataWithContentsOfURL:url];

    

    //把数据转化成图片

    UIImageView*image=[[UIImageView alloc]initWithFrame:CGRectMake(100, 300, 100, 80)];

    image.image=[UIImage imageWithData:data];

}

 

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

 

@end