多线程-GCD1

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

//iOS里面共有四种实现多线程的方式

//1、NSObject 自带了performselectoronbackground(最简单最轻量级的级别)（它是隐式的创建线程）NSThead；

//2、NSThread

//1>、第一种创建方式

NSThread *thread = [[NSThread alloc]initWithTarget:self selector:@selector(jisuanNumber) object:nil];

//这种创建的NSThread方式必须手动开启线程

[thread start];//必须开启

//1、获取当前线程

[NSThread currentThread];

//2、判断一个线程是否是主线程

[NSThread isMainThread];

NSLog(@"viewDidLoad:%@,%d",[NSThread currentThread],[NSThread isMainThread]);

//2>、第二种创建方式

[NSThread detachNewThreadSelector:@selector(jisuanNumber) toTarget:self withObject:nil];//自动开启任务

}

#pragma mark 计算ButtonDidCkicked(单线程)

- (IBAction)jisuanButtonDidClicked:(id)sender {

//1、NSObject

[self performSelectorInBackground:@selector(jisuanNumber) withObject:nil];

}

- (void)jisuanNumber {

@autoreleasepool {//必须有自动释放池

NSLog(@"%@,%d",[NSThread currentThread],[NSThread isMainThread]);

NSInteger sum = 0;

for (NSInteger i = 1; i < 1000000000; i++) {

sum += i;

}

// NSLog(@"%ld",(long)sum);

[self performSelectorOnMainThread:@selector(result:) withObject:@(sum) waitUntilDone:YES];

}

}

- (void)result:(NSNumber *)sum {

NSLog(@"%ld",(long)sum);

}