image.png

runloop說白了就是一種循環(huán)，只不過是高級的一種循環(huán)，一般的while忙等待會讓cpu一直工作不停，而runloop是一種“閑”等待，沒有事件時候，runloop會休眠，而有事件時候，則會喚醒runloop去調(diào)對應(yīng)的handler去處理

將所有網(wǎng)絡(luò)請求放在一個子線程里進(jìn)行，子線程完成任務(wù)自動銷毀，但是很多線程的創(chuàng)建和銷毀很耗資源，所以干脆把子線程放在runloop里，保證不被銷毀

NSRunloop與CFRunLoop區(qū)別、聯(lián)系

NSRunLoop

//XYNetworkingThread.h
+ (NSThread *)shareInstance;

//XYNetworkingThread.m
+ (NSThread *)shareInstance {
    static NSThread *_networkRequestThread = nil;
    static dispatch_once_t oncePredicate;
    dispatch_once(&oncePredicate, ^{
        _networkRequestThread = [[NSThread alloc] initWithTarget:self selector:@selector(addRunLoop) object:nil];
        [_networkRequestThread start];
    });
    return _networkRequestThread;
}

+ (void)addRunLoop{
    @autoreleasepool{
        [[NSThread currentThread] setName:@"XYNetworking"];
        NSRunLoop *runloop = [NSRunLoop currentRunLoop];
        [runloop addPort:[NSPort port] forMode:NSDefaultRunLoopMode];
        [runloop run];
    }
}

image.png

CFRunLoop

主要是addRunLoop方法做了修改

[[NSThread currentThread] setName:@"XYNetworking"];
// Set up a dummy runloop source to avoid spinning
CFRunLoopSourceContext noSpinCtx = {0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL};
CFRunLoopSourceRef noSpinSource = CFRunLoopSourceCreate(NULL, 0, &noSpinCtx);
CFRunLoopAddSource(CFRunLoopGetCurrent(), noSpinSource, kCFRunLoopDefaultMode);
CFRelease(noSpinSource);

// run the run loop
while (kCFRunLoopRunStopped != CFRunLoopRunInMode(kCFRunLoopDefaultMode, ((NSDate *)[NSDate distantFuture]).timeIntervalSinceReferenceDate, NO)) {
    NSLog(@"not reached assertion");
}

image.png

參考
iOS RunLoop詳解