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：
//
// 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