scroll to cellForRowAtIndex issue with swift auto layout - swift

Question

I need to scroll the table to bottom.When i write the code of scrolling the table in viewwilAppear it does not work,but when i write the same code in viewDidAppear it works but user see the scrolling. I do not want to see the user , scrolling how to make tableScrolling in ViewWillAppear.`
override func viewWillAppear(animated: Bool)
{
super.viewWillAppear(animated)
UIApplication.sharedApplication().delegate!.window!!.windowLevel = UIWindowLevelNormal
self.view.backgroundColor = UIColor.whiteColor()
viewWillAppearExecuted = true
executeCodeOfViewViewAppear()
}
func executeCodeOfViewViewAppear() {
if viewWillAppearExecuted {
viewWillAppearExecuted = false
if appNeedsAutoResize{
self.noLongerParticipantMessageLabel.font = UIUtils.getFontForApproprieteField(.Footnote).font
self.typingStatusLabel.font = UIUtils.getFontForApproprieteField(.Headline).font
}
withAnimationFlag = true
if !self.composeBar.textView.isFirstResponder()
{
// This block will execute if compose bar is first responder
self.updateTableBottomCnt(value:self.composeBar.frame.size.height)
// Update compose bar constarint
if self.composeBarBottomConstraing.constant != 0
{
self.composeBarBottomConstraing.constant = 0
}
}
self.isOpenNextScreen = false
self.checkIfloginUserisActiveMember()
self.tabBarController?.tabBar.hidden = true
ChatCommonCall.sharedInstance.currentThreadIdForPush = self.threadInfo.threadId
// This block is used for make a responder to keyboard for send message.
if shouldComposeBarFirstResponder == true {
self.composeBar.becomeFirstResponder()
shouldComposeBarFirstResponder = false
}
self.showMessageById(self.messageIdForMessageDisplay)
ChatCommonCall.sharedInstance.isChatModuleScreen = true
self.changeFrame()
self.composeBar.button.enabled = self.composeBar.text.trim().length > 0 ? true : false
/// Table frame changes.
switch self.optType
{
case .NewMessageSection:
break
case .DoNotHandle :
break
case .None :
if !(self.messageIdForMessageDisplay.isEqual(Guid.emptyGuid()))
{
self.optType = .ShowMessageOfID(id: self.messageIdForMessageDisplay)
}
else {
self.optType = .ScrollToBottom
}
break
default :
break
}
switch self.optType
{
case .NewMessageSection :
break
default :
self.handleOptType()
}
//Implemented the new observer pattern in the whole project where we suppose to refresh the screen for background sync data
//By Nikhil Kumar Saraf on 19 July 2016
Notifier.Unregister()
let observer = DatabaseObserverInfo(tName: ["chatthread","chatthreadmember","chatmessage","chatmessagereceiver","chatthumbnail","pfthumbnail","chatmessagemarker"], oType: [SyncOpType.Insert,SyncOpType.Update,SyncOpType.Delete], observer: self, stick: false, syncTrigger: SyncTriggerType.Post)
Notifier.Register(observer)
//By Balkrishan Yadav for AutoResizing UI on 30 Nov. 2016
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ChatMessageController.didChangePreferredContentSize(_:)), name:UIContentSizeCategoryDidChangeNotification, object: nil)
// This condition will execute if some one sharing image and coming to the chat message screen
//#Balkrishan Yadav
if ChatCommonCall.sharedInstance.attachmentInfo != nil {
self.addFileInComposeBar(ChatCommonCall.sharedInstance.attachmentInfo!)
ChatCommonCall.sharedInstance.attachmentInfo = nil
let dispatchTime: dispatch_time_t = dispatch_time(DISPATCH_TIME_NOW, Int64(0.3 * Double(NSEC_PER_SEC)))
dispatch_after(dispatchTime, dispatch_get_main_queue(), {
// your function here
// self.changeController(true)
})
}
}
}
func handleOptType(callFromViewDidAppear:Bool = false) {
switch optType {
case .ScrollToBottom : // No new message is available. show last message. self.messageTableView.setContentOffset(CGPointMake(0,CGFloat.max), animated: !isCameFromThreadComposer)
break
default:
// do nothing
}

Answer 1

If you don't want the scrolling to be animated you just have to pass false as the animated argument to the scrolling function. For example :
tableView.scrollToRow(at: indexPath, at: .top, animated: false)
This function would scroll the indexPath's row to the top of the table view without any animation.