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多线程有4种
NSObject---NSObject自带的,但是他不能对数据进行保护
NSThread ---过于复杂,使用起来不够方便
NSOperationQueue ---操作队列,管理线程,内部有一个线程池,负责对现有的线程进行管理/重用
GDC(grand central dispatch); ----基于C的多线程解决方案
队列有两种(串行/并行)
MainViewController.m
#import "MainViewController.h"
#import "MyOperation.h"
@interface MainViewController ()
@property (nonatomic , retain)UIImageView *p_w_picpathView;
@end
@implementation MainViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(110, 100, 100, 30)];
[button setTitle:@"按钮" forState:UIControlStateNormal];
button.backgroundColor = [UIColor orangeColor];
button.layer.cornerRadius = 5;
[self.view addSubview:button];
[button addTarget:self action:@selector(GCDAction:) forControlEvents:UIControlEventTouchUpInside];
[button release];
self.p_w_picpathView = [[UIImageView alloc] initWithFrame:CGRectMake(40, 150, 240, 300)];
self.p_w_picpathView.backgroundColor = [UIColor cyanColor];
[self.view addSubview:self.p_w_picpathView];
[_p_w_picpathView release];
}
- (void)buttonClick:(UIButton *)button
{
NSLog(@"判断当前线程是不是主线程%d",[NSThread isMainThread]);
//让当前的线程休眠3秒
[NSThread sleepForTimeInterval:3];
NSLog(@"休眠结束");
NSLog(@"当前线程: %@",[NSThread currentThread]) ;
int a = 0;
for (int i = 0 ; i < 600000000; i++) {
a++;
}
NSLog(@"%d",a);
}
- (void)NSObjectAction:(UIButton *)button
{
//1.多线程的实现方式:NSObject自带的
//绑定一个方法,然后给他一个参数 优点:简介快速,缺点:不能对数据进行保护
[self performSelectorInBackground:@selector(buttonClick:) withObject:button];
}
- (void)threadAciton:(UIButton *)button
{
//2.NStrread类
//这个类ude一个对象,就代表一个线程 优点:可以控制线程的所有方面 缺点:太复杂,使用起来不方便
NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(buttonClick:) object:button];
thread.name = @"刘亚芳";
//开始执行子线程
[thread start];
[thread release];
}
- (void)operationAction:(UIButton *)button
{
//NSOperation类
//本身不能够实现多线程操作,代表一个任务(进程),安排在某个线程里面
MyOperation *opreation = [[MyOperation alloc] init];
//开始执行任务,执行的任务会在当前执行
[opreation start];
[opreation release];
// NSInvocationOperation *op1 = [NSInvocationOperation alloc] initWithTarget:<#(id)#> selector:<#(SEL)#> object:<#(id)#>
// NSBlockOperation *op2 = [NSBlockOperation blockOperationWithBlock:<#^(void)block#>]
}
- (void)poerationQueueAction:(UIButton *)button
{
//NSOperationQueue 操作队列(管理线程,线程池) 队列有两类:(并行/串行)
//内部有一个线程池,负责对现有的线程进行管理/重用
//创建一个新的队列
//主队列是一个串行队列
NSOperationQueue *queue = [[NSOperationQueue alloc] init];
//设置一个最大并发数(如果最大并发数为1,那么就为串行,否则为并行)
[queue setMaxConcurrentOperationCount:1];
//向队列中添加任务
MyOperation *op1 = [[MyOperation alloc] init];
MyOperation *op2 = [[MyOperation alloc] init];
MyOperation *op3 = [[MyOperation alloc] init];
MyOperation *op4 = [[MyOperation alloc] init];
[queue addOperation:op1];
[queue addOperation:op2];
[queue addOperation:op3];
[queue addOperation:op4];
[op1 release];
[op2 release];
[op3 release];
[op4 release];
}
- (void)GCDAction:(UIButton *)button
{
//GCD: grand central dispatch 基于C的多线程解决方案
//1.创建一个调度队列
//参数1: 队列名字 参数2:队列的类型(串行/并行)
//DISPATCH_QUEUE_CONCURRENT---并行队列
//DISPATCH_QUEUE_SERIAL ---串行队列
dispatch_queue_t myQueue = dispatch_queue_create("liuyafang", DISPATCH_QUEUE_SERIAL);
//2.使用的队列
//参数1:要在哪个队列执行 参数2:要执行的内容
dispatch_async(myQueue, ^{
//任务1
[self buttonClick:button];
});
dispatch_async(myQueue, ^{
//任务2
NSLog(@"===========");
});
//使用系统的队列
//系统提供了5个队列,1个串行队列(主队列),4个并行队列(全局队列)
//获取系统的主队列
dispatch_queue_t mainQueue = dispatch_get_main_queue();
dispatch_async(mainQueue, ^{
//执行在主队列中要做的任务
//全部的UI任务(reloadDate ,给试图赋值)
});
//获取全局队列
//参数1:获取哪一个全局队列 参数2:给未来使用的(必须填写0)
dispatch_queue_t globalQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
//GCD的常见用法
//在全局队列中请求数据
dispatch_async(globalQueue, ^{
NSString *str = @"https://cache.yisu.com/upload/information/20200312/67/251264.jpg";
NSURL *url = [NSURL URLWithString:str];
//请求网络地址数据的同步方法
//因为这个方法在子线程(全局队列)中执行,所以不需要考虑死线程的问题
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *p_w_picpath = [UIImage p_w_picpathWithData:data];
//所有刷新UI的操作都必须回到主队列进行(跳回到子线程)
dispatch_async(mainQueue, ^{
self.p_w_picpathView.p_w_picpath = p_w_picpath;
});
});
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(4 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
NSLog(@"乔老爷不该死啊!!!");
});
//一段代码值执行一次,(单列的创建)
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
NSLog(@"只执行一次");
});
}
- (void)dealloc
{
[_p_w_picpathView release];
[super dealloc];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
@endMyOperation.h
看继承关系---这个是继承与NSOperation
#import <Foundation/Foundation.h> @interface MyOperation : NSOperation @end
MyOperation.m
#import "MyOperation.h"
@implementation MyOperation
- (void)main
{
//自己定义的Operation的类,需要在mian方法中写要执行的任务内容
NSLog(@"当前线程:%@",[NSThread currentThread]);
NSLog(@"是不是主线程尼:%d",[NSThread isMainThread]);
int a = 0;
for (int i = 0 ; i < 600000000; i++) {
a++;
}
NSLog(@"%d",a);
}
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