iOS開發多線程篇—線程間的通信

iOS開發多線程篇—線程間的通信

一、簡單說明

線程間通信：在1個程序中，線程往往不是孤立存在的，多個線程之間需要經常進行通信

線程間通信的展現

1個線程傳遞資料給另1個線程

在1個線程中執行完特定任務後，轉到另1個線程繼續執行任務

線程間通信常用方法

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

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

線程間通信示例 – 圖檔下載下傳

代碼1：

1 //
 2 //  YYViewController.m
 3 //  06-NSThread04-線程間通信
 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 // 在子線程中調用download方法下載下傳圖檔
25     [self performSelectorInBackground:@selector(download) withObject:nil];
26 }
27 
28  
29 
30 -(void)download
31 {
32     //1.根據URL下載下傳圖檔
33     //從網絡中下載下傳圖檔
34     NSURL *urlstr=[NSURL URLWithString:@"fdsf"];
35 
36     //把圖檔轉換為二進制的資料
37     NSData *data=[NSData dataWithContentsOfURL:urlstr];//這一行操作會比較耗時
38 
39     //把資料轉換成圖檔
40     UIImage *image=[UIImage imageWithData:data];
41  
42     //2.回到主線程中設定圖檔
43     [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];
44 }
45 
46  
47 
48 //設定顯示圖檔
49 -(void)settingImage:(UIImage *)image
50 {
51     self.iconView.image=image;
52 }
53 
54 @end      

代碼2：

1 //
 2 //  YYViewController.m
 3 //  06-NSThread04-線程間通信
 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 // 在子線程中調用download方法下載下傳圖檔
27 
28     [self performSelectorInBackground:@selector(download) withObject:nil];
29 }
30 
31  
32 -(void)download
33 {
34 
35     //1.根據URL下載下傳圖檔
36     //從網絡中下載下傳圖檔
37     NSURL *urlstr=[NSURL URLWithString:@"fdsf"];
38 
39     //把圖檔轉換為二進制的資料
40     NSData *data=[NSData dataWithContentsOfURL:urlstr];//這一行操作會比較耗時
41 
42     //把資料轉換成圖檔
43     UIImage *image=[UIImage imageWithData:data];
44 
45     //2.回到主線程中設定圖檔
46     //第一種方式
47 //    [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];
48 
49     //第二種方式
50     //    [self.imageView performSelector:@selector(setImage:) onThread:[NSThread mainThread] withObject:image waitUntilDone:NO];
51 
52     //第三種方式
53    [self.iconView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];
54 }
55 
56 
57 //設定顯示圖檔
58 //-(void)settingImage:(UIImage *)image
59 //{
60 //    self.iconView.image=image;
61 //}
62 
63 @end