iOS開發多線程篇—線程間的通訊

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iOS開發多線程篇—線程間的通訊

 

一、簡單說明

線程間通訊：在1個進程中，線程往往不是孤立存在的，多個線程之間需要經常進行通訊

 

線程間通訊的體現

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

 

線程間通訊常用方法

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

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

 

線程間通訊樣本 – 圖片下載

代碼1：

 1 // 2 //  YYViewController.m 3 //  06-NSThread04-線程間通訊 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 @end13 14 @implementation YYViewController15 16 - (void)viewDidLoad17 {18     [super viewDidLoad];19 }20 21 -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event22 {23 24 // 在子線程中調用download方法下載圖片25     [self performSelectorInBackground:@selector(download) withObject:nil];26 }27 28  29 30 -(void)download31 {32     //1.根據URL下載圖片33     //從網路中下載圖片34     NSURL *urlstr=[NSURL URLWithString:@"fdsf"];35 36     //把圖片轉換為二進位的資料37     NSData *data=[NSData dataWithContentsOfURL:urlstr];//這一行操作會比較耗時38 39     //把資料轉換成圖片40     UIImage *image=[UIImage imageWithData:data];41  42     //2.回到主線程中設定圖片43     [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];44 }45 46  47 48 //設定顯示圖片49 -(void)settingImage:(UIImage *)image50 {51     self.iconView.image=image;52 }53 54 @end

 

代碼2：

 1 // 2 //  YYViewController.m 3 //  06-NSThread04-線程間通訊 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 @end15 16 @implementation YYViewController17 18 - (void)viewDidLoad19 {20     [super viewDidLoad];21 }22 23  24 -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event25 {26 // 在子線程中調用download方法下載圖片27 28     [self performSelectorInBackground:@selector(download) withObject:nil];29 }30 31  32 -(void)download33 {34 35     //1.根據URL下載圖片36     //從網路中下載圖片37     NSURL *urlstr=[NSURL URLWithString:@"fdsf"];38 39     //把圖片轉換為二進位的資料40     NSData *data=[NSData dataWithContentsOfURL:urlstr];//這一行操作會比較耗時41 42     //把資料轉換成圖片43     UIImage *image=[UIImage imageWithData:data];44 45     //2.回到主線程中設定圖片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 //設定顯示圖片58 //-(void)settingImage:(UIImage *)image59 //{60 //    self.iconView.image=image;61 //}62 63 @end