ios - 当键盘出现时滚动到底部导致崩溃

Question

当键盘出现时，我想将桌面 View 滚动到底部。但我从用户那里收到了很多崩溃报告。

我的代码:

func keyboardWillShow(_ notification: Foundation.Notification) {
    var info = notification.userInfo!
    let keyboardFrame: CGRect = (info[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

    self.view.layoutIfNeeded()
    UIView.animate(withDuration: 0.2, animations: {
        self.bottomCons.constant = keyboardFrame.size.height

        self.view.layoutIfNeeded()
    }) 
    let numberOfRows = tableView.numberOfRows(inSection: 0)
    if numberOfRows != 0 {
        do {
            try tableView.scrollToRow(at: IndexPath(row: numberOfRows-1, section: 0), at: .bottom, animated: false)
        }catch {
            print("error")
        }
    }

}

崩溃日志:

Fatal Exception: NSRangeException
0  CoreFoundation                 0x18f3bafe0 __exceptionPreprocess
1  libobjc.A.dylib                0x18de1c538 objc_exception_throw
2  CoreFoundation                 0x18f299200 -[__NSArrayM removeObjectAtIndex:]
3  UIKit                          0x195826f90 -[UITableView _existingCellForRowAtIndexPath:]
4  UIKit                          0x195836a50 -[UITableView _heightForRowAtIndexPath:]
5  UIKit                          0x1956291c0 -[UISectionRowData heightForRow:inSection:canGuess:]
6  UIKit                          0x195628ebc -[UITableViewRowData rectForRow:inSection:heightCanBeGuessed:]
7  UIKit                          0x19562c21c -[UITableView rectForRowAtIndexPath:]
8  UIKit                          0x195704180 -[UITableView _contentOffsetForScrollingToRowAtIndexPath:atScrollPosition:]
9  UIKit                          0x195703c84 -[UITableView scrollToRowAtIndexPath:atScrollPosition:animated:]
10 Ribony                         0x1000a3044 ChatViewController.keyboardWillShow(Notification) -> () (ChatViewController.swift)
11 Ribony                         0x1000a07d4 @objc ChatViewController.showConnectedLayout(Notification) -> ()
12 CoreFoundation                 0x18f3555f4 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__
13 CoreFoundation                 0x18f354d08 _CFXRegistrationPost
14 CoreFoundation                 0x18f354a84 ___CFXNotificationPost_block_invoke
15 CoreFoundation                 0x18f3c37a8 -[_CFXNotificationRegistrar find:object:observer:enumerator:]
16 CoreFoundation                 0x18f29895c _CFXNotificationPost
17 Foundation                     0x18fdaa930 -[NSNotificationCenter postNotificationName:object:userInfo:]
18 UIKit                          0x195ed0190 -[UIInputWindowController postStartNotifications:withInfo:]
19 UIKit                          0x195ed0edc __48-[UIInputWindowController viewDidLayoutSubviews]_block_invoke
20 UIKit                          0x195ecdc04 -[UIInputWindowController performWithSafeTransitionFrames:]
21 UIKit                          0x195ed098c -[UIInputWindowController viewDidLayoutSubviews]
22 UIKit                          0x1954e90f4 -[UIView(CALayerDelegate) layoutSublayersOfLayer:]
23 QuartzCore                     0x1926d9274 -[CALayer layoutSublayers]
24 QuartzCore                     0x1926cdde8 CA::Layer::layout_if_needed(CA::Transaction*)
25 UIKit                          0x1954fd814 -[UIView(Hierarchy) layoutBelowIfNeeded]
26 UIKit                          0x195ecc4cc -[UIInputSetHostView layoutIfNeeded]
27 UIKit                          0x195c79310 -[_UIRemoteKeyboards controllerDidLayoutSubviews:]
28 UIKit                          0x195d49364 -[UICompatibilityInputViewController viewDidLayoutSubviews]
29 UIKit                          0x1954e90f4 -[UIView(CALayerDelegate) layoutSublayersOfLayer:]
30 QuartzCore                     0x1926d9274 -[CALayer layoutSublayers]
31 QuartzCore                     0x1926cdde8 CA::Layer::layout_if_needed(CA::Transaction*)
32 UIKit                          0x1954fd814 -[UIView(Hierarchy) layoutBelowIfNeeded]
33 UIKit                          0x195ecc4cc -[UIInputSetHostView layoutIfNeeded]
34 UIKit                          0x195ed4da0 -[UIInputWindowController _updateBackdropViews]
35 UIKit                          0x195d4823c -[UICompatibilityInputViewController setInputMode:]
36 CoreFoundation                 0x18f3555f4 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__
37 CoreFoundation                 0x18f354d08 _CFXRegistrationPost
38 CoreFoundation                 0x18f354a84 ___CFXNotificationPost_block_invoke
39 CoreFoundation                 0x18f3c37a8 -[_CFXNotificationRegistrar find:object:observer:enumerator:]
40 CoreFoundation                 0x18f29895c _CFXNotificationPost
41 Foundation                     0x18fdaa930 -[NSNotificationCenter postNotificationName:object:userInfo:]
42 UIKit                          0x195908be4 -[UIKeyboardImpl setKeyboardInputMode:userInitiated:updateIndicator:executionContext:]
43 UIKit                          0x19590a388 -[UIKeyboardImpl setInputModeToNextInPreferredListWithExecutionContext:]
44 UIKit                          0x1956aed88 -[UIKeyboardLayoutStar completeSendStringActionForTouchUp:withActions:timestamp:interval:didLongPress:prevActions:executionContext:]
45 UIKit                          0x1956a1f18 -[UIKeyboardLayoutStar completeRetestForTouchUp:timestamp:interval:executionContext:]
46 UIKit                          0x19592bbb8 __45-[UIKeyboardLayout touchUpTaskForTouchState:]_block_invoke
47 UIKit                          0x195515e0c -[UIKeyboardTaskQueue continueExecutionOnMainThread]
48 UIKit                          0x19592b868 -[UIKeyboardLayout _touchEndedProcessingForTouches:]
49 UIKit                          0x195520390 -[UIWindow _sendTouchesForEvent:]
50 UIKit                          0x19551b728 -[UIWindow sendEvent:]
51 UIKit                          0x1954ec33c -[UIApplication sendEvent:]
52 UIKit                          0x195ce6014 __dispatchPreprocessedEventFromEventQueue
53 UIKit                          0x195ce0770 __handleEventQueue
54 UIKit                          0x195ce0b9c __handleHIDEventFetcherDrain
55 CoreFoundation                 0x18f36942c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
56 CoreFoundation                 0x18f368d9c __CFRunLoopDoSources0
57 CoreFoundation                 0x18f3669a8 __CFRunLoopRun
58 CoreFoundation                 0x18f296da4 CFRunLoopRunSpecific
59 GraphicsServices               0x190d00074 GSEventRunModal
60 UIKit                          0x195551058 UIApplicationMain
61 Ribony                         0x10003f11c main (AppDelegate.swift:15)
62 libdyld.dylib                  0x18e2a559c start

如何解决这个问题？

Answer 1

我确信问题出在这里

UIView.animate(withDuration: 0.2, animations: {
    self.bottomCons.constant = keyboardFrame.size.height

    self.view.layoutIfNeeded()
}) 

...

try tableView.scrollToRow(at: IndexPath(row: numberOfRows-1, section: 0), at: .bottom, animated: false)

您正在重新加载布局并尝试在同一时刻滚动，您应该在之后或之前滚动。可能是我不对，但这通常就是问题所在。