一、pthread的使用（幾乎不用）

#import "ViewController.h"
// 1.引入pthread頭文件: #import <pthread.h>
#import <pthread.h>

@interface ViewController ()

@end

@implementation ViewController

void *run(void *data) {
    for (int i = 0; i<10000; i++) {
        // 調(diào)用NSThread的類方法currentThread返回的是
        // 當(dāng)前代碼所在線程的相關(guān)信息（線程地址,線程數(shù)量,當(dāng)前線程的名字）
        NSLog(@"touchesBegan ---- %d --- %@", i, [NSThread currentThread]);
    }
    return 0;
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    // 2.創(chuàng)建線程
    pthread_t myRestict;
    // 3.啟動(dòng)線程，調(diào)用run方法，注意??run方法的返回值必須為空！
    pthread_create(&myRestict, NULL, run, NULL);
}

@end

二、NSThread的使用（偶爾使用）

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)download:(NSString *)url {
    NSLog(@"download something --- %@ --- %@", url, [NSThread currentThread]);
}

/**
 創(chuàng)建線程的方式1
 */
- (void)createThread1 {
    // 1.創(chuàng)建線程
    NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(download:) object:@"http://a.jpg"];
    
    // 2.啟動(dòng)線程（調(diào)用self的download方法）
    [thread start];
    
    // 判斷thread這個(gè)線程是否是主線程
    // [thread isMainThread];
    
    // 判斷當(dāng)前方法是否為主線程
    // [NSThread isMainThread];
    
    // 設(shè)置線程的名字
    // [thread setName:@"download_thread"];
    // thread.name = @"downloadThread";
}

/**
 創(chuàng)建線程的方式2: 創(chuàng)建線程后自動(dòng)啟動(dòng)
 */
- (void)createThread2 {
    [NSThread detachNewThreadSelector:@selector(download:) toTarget:self withObject:@"http://b.png"];
}

/**
 創(chuàng)建線程的方式3: 隱式創(chuàng)建線程后自動(dòng)啟動(dòng)
 */
- (void)createThread3 {
    [self performSelectorInBackground:@selector(download:) withObject:@"http://c.gif"];
}

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [self createThread1];
    // [self createThread2];
    // [self createThread3];
}

@end