I have a question about xcode7.x Swift (about reloadData())

This is the current situation.

The part I want to implement is to select a cell in the tableView Controller and put the data (using core data x) that fits the cell into the variable in the collectionView and reset the view with the contents.

It's a question.

There is no problem with the initial startup, but the function works well when you select a cell in the tableViewController.After self.collectionView.reloadData()


import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {  //Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP,  subcode=0x0)

There is an error in the . I don't know why it flies. It's been blocked for a week

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'UICollectionView must be initialized with a non-nil layout parameter'
*** *** First throw call stack:
(
    0   CoreFoundation                      0x000000010c219d85 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x000000010dfbddeb objc_exception_throw + 48
    2   CoreFoundation                      0x000000010c219cbd +[NSException raise:format:] + 205
    3   UIKit                               0x000000010d2b3612 -[UICollectionView initWithFrame:collectionViewLayout:] + 76
    4   UIKit                               0x000000010d2f1622 -[UICollectionViewController _newCollectionViewWithFrame:collectionViewLayout:] + 108
    5   UIKit                               0x000000010d2f07b1 -[UICollectionViewController loadView] + 675
    6   UIKit                               0x000000010cbdc560 -[UIViewController loadViewIfRequired] + 138
    7   UIKit                               0x000000010d2f12e4 -[UICollectionViewController collectionView] + 22
    8   Home Control Client                 0x000000010c010418 _TFC19Home_Control_Client28ControllerListCollectionView21GetZoneControllerListfVCS_13ZoneListBrain4zoneT_ + 1400
    9   Home Control Client                 0x000000010c01731c _TFC19Home_Control_Client13ZoneListBrain23DeliveryAtTheZoneNumberfSiT_ + 620
    10  Home Control Client                 0x000000010c014b78 _TFC19Home_Control_Client17ZoneListTableView9tableViewfTCSo11UITableView23didSelectRowAtIndexPathCSo11NSIndexPath_T_ + 504
    11  Home Control Client                 0x000000010c014bff _TToFC19Home_Control_Client17ZoneListTableView9tableViewfTCSo11UITableView23didSelectRowAtIndexPathCSo11NSIndexPath_T_ + 79
    12  UIKit                               0x000000010cb891c6 -[UITableView _selectRowAtIndexPath:animated:scrollPosition:notifyDelegate:] + 1887
    13  UIKit                               0x000000010cb8941b -[UITableView _userSelectRowAtPendingSelectionIndexPath:] + 388
    14  UIKit                               0x000000010ca4df62 _runAfterCACommitDeferredBlocks + 317
    15  UIKit                               0x000000010ca61e4c _cleanUpAfterCAFlushAndRunDeferredBlocks + 95
    16  UIKit                               0x000000010ca6e147 _afterCACommitHandler + 90
    17  CoreFoundation                      0x000000010c13ec37 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    18  CoreFoundation                      0x000000010c13eba7 __CFRunLoopDoObservers + 391
    19  CoreFoundation                      0x000000010c1347fb __CFRunLoopRun + 1147
    20  CoreFoundation                      0x000000010c1340f8 CFRunLoopRunSpecific + 488
    21  GraphicsServices                    0x00000001108afad2 GSEventRunModal + 161
    22  UIKit                               0x000000010ca41f09 UIApplicationMain + 171
    23  Home Control Client                 0x000000010c01a562 main + 114
    24  libdyld.dylib                       0x000000010ea8192d start + 1
    25  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

swift ios xcode

2022-09-21 14:34

2 Answers

Try adding UICollectionViewFlowLayout to viewDidLoad().

        let aFlowLayout = UICollectionViewFlowLayout()
        aFlowLayout.itemSize = CGSizeMake(100, 22)

        self.collectionView.collectionViewLayout = aFlowLayout

It is essential to put it in the collection view when not using autoLayout, but I am not sure if this is right because it occurs when the layout setting is not initialized. Please try putting it in and check if it works. I'm sorry it's not an exact answer

2022-09-21 14:34

Did you solve it?I keep getting stuck with the same problem

2022-09-21 14:34

If you have any answers or tips

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