iOS开发多线程篇—线程间的通信

iOS开发多线程篇—线程间的通信

 

一、简单说明

线程间通信：在1个进程中，线程往往不是孤立存在的，多个线程之间需要经常进行通信

 

线程间通信的体现

1个线程传递数据给另1个线程

在1个线程中执行完特定任务后，转到另1个线程继续执行任务

 

线程间通信常用方法

- (void)performSelectorOnMainThread:(SEL)aSelector withObject:(id)arg waitUntilDone:(BOOL)wait;

- (void)performSelector:(SEL)aSelector onThread:(NSThread *)thr withObject:(id)arg waitUntilDone:(BOOL)wait;

 

线程间通信示例 – 图片下载

代码1：

 1 //

 2 //  YYViewController.m

 3 //  06-NSThread04-线程间通信

 4 //

 5 //  Created by apple on 14-6-23.

 6 //  Copyright (c) 2014年 itcase. All rights reserved.

 7 //

 8 

 9 #import "YYViewController.h"

10 @interface YYViewController ()

11 @property (weak, nonatomic) IBOutlet UIImageView *iconView;

12 @end

13 

14 @implementation YYViewController

15 

16 - (void)viewDidLoad

17 {

18     [super viewDidLoad];

19 }

20 

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

22 {

23 

24 // 在子线程中调用download方法下载图片

25     [self performSelectorInBackground:@selector(download) withObject:nil];

26 }

27 

28  

29 

30 -(void)download

31 {

32     //1.根据URL下载图片

33     //从网络中下载图片

34     NSURL *urlstr=[NSURL URLWithString:@"fdsf"];

35 

36     //把图片转换为二进制的数据

37     NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时

38 

39     //把数据转换成图片

40     UIImage *image=[UIImage imageWithData:data];

41  

42     //2.回到主线程中设置图片

43     [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];

44 }

45 

46  

47 

48 //设置显示图片

49 -(void)settingImage:(UIImage *)image

50 {

51     self.iconView.image=image;

52 }

53 

54 @end

 

代码2：

 1 //

 2 //  YYViewController.m

 3 //  06-NSThread04-线程间通信

 4 //

 5 //  Created by apple on 14-6-23.

 6 //  Copyright (c) 2014年 itcase. All rights reserved.

 7 //

 8 

 9 #import "YYViewController.h"

10 #import <NSData.h>

11 

12 @interface YYViewController ()

13 @property (weak, nonatomic) IBOutlet UIImageView *iconView;

14 @end

15 

16 @implementation YYViewController

17 

18 - (void)viewDidLoad

19 {

20     [super viewDidLoad];

21 }

22 

23  

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

25 {

26 // 在子线程中调用download方法下载图片

27 

28     [self performSelectorInBackground:@selector(download) withObject:nil];

29 }

30 

31  

32 -(void)download

33 {

34 

35     //1.根据URL下载图片

36     //从网络中下载图片

37     NSURL *urlstr=[NSURL URLWithString:@"fdsf"];

38 

39     //把图片转换为二进制的数据

40     NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时

41 

42     //把数据转换成图片

43     UIImage *image=[UIImage imageWithData:data];

44 

45     //2.回到主线程中设置图片

46     //第一种方式

47 //    [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];

48 

49     //第二种方式

50     //    [self.imageView performSelector:@selector(setImage:) onThread:[NSThread mainThread] withObject:image waitUntilDone:NO];

51 

52     //第三种方式

53    [self.iconView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];

54 }

55 

56 

57 //设置显示图片

58 //-(void)settingImage:(UIImage *)image

59 //{

60 //    self.iconView.image=image;

61 //}

62 

63 @end