ios - 分配文本时 UITextView 不滚动

Question

我正在创建一个具有 UIImageView 和 UITextView 的应用程序。我从服务器获取文本和图像，但是当我将大量文本分配给 UITextView 时，UITextView 不会滚动。有几次它开始滚动大量文本。我不确定我做错了什么？但大多数时候它不会滚动并且看起来卡住了。我检查了输出窗口，没有看到任何约束被破坏。

func locationManager(manager: CLLocationManager!, didRangeBeacons beacons: [AnyObject]!, inRegion region: CLBeaconRegion!) {

    if beacons.count == 0 {
        return
    }

    for beacon in beacons as! [CLBeacon] {

       // we are only interested in beacons that are near or immediate!
        if beacon.proximity == .Near || beacon.proximity == .Immediate {

        let closestTourBeacon = beaconByMajorAndMinorId(beacon.major, minorId: beacon.minor)

        if self.lastBeacon == nil {
            self.lastBeacon = closestTourBeacon
        }
        else if isEqualToLastBeacon(closestTourBeacon)
        {
            continue
        }
        else {
            self.lastBeacon = closestTourBeacon
        }

            dispatch_async(dispatch_get_main_queue(), { () -> Void in

                // vibrate the phone
                //AudioServicesPlayAlertSound(SystemSoundID(kSystemSoundID_Vibrate))

                println("Assinging the text property")

                self.textTextView.text = closestTourBeacon.text <<=== THIS LINE
                self.title = closestTourBeacon.title
                self.photoImageView.load(closestTourBeacon.imageURL!)

                let originalFrame = self.photoImageView.frame
                self.photoImageView.center = CGPointMake(self.photoImageView.center.x, -100)

                UIView.animateWithDuration(1.0, delay: 0.0, usingSpringWithDamping: 0.5, initialSpringVelocity: 1.0, options: UIViewAnimationOptions.TransitionNone, animations: { () -> Void in

                    self.photoImageView.frame = originalFrame

                    }, completion: { (finished :Bool) -> Void in

                })
        })

        }

    }

}

更新:我还注意到，当应用程序首次启动时，即使有很多文本要滚动，UITextView 也会完全卡住。之后，如果我继续尝试滚动 UITextView 并使用新数据获取和设置文本，它就会脱离卡住状态并开始滚动而不会出现任何问题。

Answer 1

如果天气太冷，请将其从主队列中移除。

dispatch_queue_t myQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0);

    dispatch_async(myQueue, ^{
        //update text
    });
    //Release queue
    dispatch_release(myQueue);

另请查看 https://www.youtube.com/watch?v=GvsEhDEGO_k我觉得你的问题可能是更新太快了