iOS 多线程篇4—线程间的通信

来源：互联网发布：麦当劳上海数据编辑：程序博客网时间：2024/05/17 01:21

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：

////  YYViewController.m//  06-NSThread04-线程间通信////  Created by apple on 14-6-23.//  Copyright (c) 2014年 itcase. All rights reserved.//#import "YYViewController.h"@interface YYViewController ()@property (weak, nonatomic) IBOutlet UIImageView *iconView;@end@implementation YYViewController- (void)viewDidLoad{    [super viewDidLoad];}-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{// 在子线程中调用download方法下载图片    [self performSelectorInBackground:@selector(download) withObject:nil];}-(void)download{    //1.根据URL下载图片    //从网络中下载图片    NSURL *urlstr=[NSURL URLWithString:@"fdsf"];    //把图片转换为二进制的数据    NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时    //把数据转换成图片    UIImage *image=[UIImage imageWithData:data];    //2.回到主线程中设置图片    [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];}//设置显示图片-(void)settingImage:(UIImage *)image{    self.iconView.image=image;}@end

代码2：

////  YYViewController.m//  06-NSThread04-线程间通信////  Created by apple on 14-6-23.//  Copyright (c) 2014年 itcase. All rights reserved.//#import "YYViewController.h"#import <NSData.h>@interface YYViewController ()@property (weak, nonatomic) IBOutlet UIImageView *iconView;@end@implementation YYViewController- (void)viewDidLoad{    [super viewDidLoad];}-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{// 在子线程中调用download方法下载图片    [self performSelectorInBackground:@selector(download) withObject:nil];}-(void)download{    //1.根据URL下载图片    //从网络中下载图片    NSURL *urlstr=[NSURL URLWithString:@"fdsf"];    //把图片转换为二进制的数据    NSData *data=[NSData dataWithContentsOfURL:urlstr];//这一行操作会比较耗时    //把数据转换成图片    UIImage *image=[UIImage imageWithData:data];    //2.回到主线程中设置图片    //第一种方式//    [self performSelectorOnMainThread:@selector(settingImage:) withObject:image waitUntilDone:NO];    //第二种方式    //    [self.imageView performSelector:@selector(setImage:) onThread:[NSThread mainThread] withObject:image waitUntilDone:NO];    //第三种方式   [self.iconView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];}//设置显示图片//-(void)settingImage:(UIImage *)image//{//    self.iconView.image=image;//}@end

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