获取＆＃39;此查询具有出色的网络连接。＆＃39;

Question

我正在＆＃39;此查询具有出色的网络连接。＆＃39;

我知道时间只允许一个查询，我认为这是我在这里所做的事情，但显然不是......

retrieveFromParse位于viewDidLoad。

08-13 21:11:21.898    1233-2167/? V/WindowManager﹕ Adding window Window{bd59a00 u0 com.cheatsheet.servercheck/com.cheatsheet.servercheck.MainActivity} at 2 of 6 (before Window{18c764e7 u0 Starting com.cheatsheet.servercheck})
08-13 21:11:21.904    2453-2468/? D/Http Connection﹕ failed to connect to /127.0.0.1 (port 80): connect failed: ECONNREFUSED (Connection refused)
08-13 21:11:21.945    2453-2469/? D/﹕ HostConnection::get() New Host Connection established 0xb43e0130, tid 2469
08-13 21:11:21.958    2453-2469/? I/OpenGLRenderer﹕ Initialized EGL, version 1.4
08-13 21:11:21.995    2453-2469/? D/OpenGLRenderer﹕ Enabling debug mode 0
08-13 21:11:22.015    2453-2469/? W/EGL_emulation﹕ eglSurfaceAttrib not implemented
08-13 21:11:22.015    2453-2469/? W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xb43cd940, error=EGL_SUCCESS
08-13 21:11:22.667    1233-1256/? I/ActivityManager﹕ Displayed com.cheatsheet.servercheck/.MainActivity: +950ms

Answer 1

问题在于：

if ([self.objects count] == 0) {
    query.cachePolicy = kPFCachePolicyCacheThenNetwork;
}

您在后台拨打电话后呼叫。换句话说，您正在尝试修改当前正在后台制作的query - 触发错误。试试这个：

-(void) retrieveFromParse{

    PFQuery *query = [PFQuery queryWithClassName:self.parseClassName];
    [query whereKey:@"photo" equalTo:[PFObject objectWithoutDataWithClassName:@"photoObject" objectId:self.currentObjectID]];
    [query orderByDescending:@"createdAt"];

    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
        // The find succeeded.
            NSLog(@"Successfully retrieved %d scores.", (int)objects.count);
            // Do something with the found objects
            for (PFObject *object in objects) {
                NSLog(@"%@", object.objectId);

                self.commentArray = [object objectForKey:@"comment"];
            }
        } else {
            // Log details of the failure
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }

        // If no objects are loaded in memory, we look to the cache
        // first to fill the table and then subsequently do a query
        // against the network.
        if ([self.objects count] == 0) {
            query.cachePolicy = kPFCachePolicyCacheThenNetwork;
        }
    }];
}