ios - UITableView 在 vi​​ewDidLoad 的中间被初始化？

Question

我有一个正在初始化的 VC，其中有一个 View。 View 中有一个 UITableView、UIButton 和 UIImage。

突然之间，我搞砸了按钮属性，哇:

Assertion failure in -[UITableView _createPreparedCellForGlobalRow:withIndexPath:]

进一步挖掘后，是因为我的代码:

UINib *animCellNib = [UINib nibWithNibName:@"IoUISEAnimationDetailListingCell" bundle:nil];
[animationDetailsTableView registerNib:animCellNib forCellReuseIdentifier:@"AnimationDetailListingCell"];

没有被执行。进一步挖掘显示在我的 viewDidLoad 方法的顶部，它跳转到初始化 tableView。因此，从我的方法名称跟踪中，您可以看到它以 numberOfSectionsInTableView 开头。虽然这只发生在我的 viewDidLoad

中的几行中

2011-10-12 15:43:42.113 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - initWithNibName:bundle:
2011-10-12 15:43:42.116 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - viewDidLoad
Current language:  auto; currently objective-c
2011-10-12 15:43:49.017 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - numberOfSectionsInTableView:
2011-10-12 15:43:49.017 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - tableView:titleForHeaderInSection:
2011-10-12 15:43:49.017 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - tableView:titleForFooterInSection:
2011-10-12 15:43:49.017 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - tableView:numberOfRowsInSection:
2011-10-12 15:43:49.017 io[5052:11903] <IoUISEAnimationDetailsViewController: 0x764c460> - tableView:cellForRowAtIndexPath:
2011-10-12 15:43:49.017 io[5052:11903] *** Assertion failure in -[UITableView _createPreparedCellForGlobalRow:withIndexPath:], /SourceCache/UIKit_Sim/UIKit-1912.3/UITableView.m:6072
2011-10-12 15:43:49.018 io[5052:11903] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:'

在 viewDidLoad 方法中，在我设置 saveButton.titleLabel.lineBreakMode 之后和 saveButton setBackgroundImage:newImage 之前，它跳转到 numberOfSectionsInTableView 方法。

由于我的 registerNib: forCellReuseIdentifier: 代码在按钮代码之后，单元格 Nib 未注册，因此导致我的 dequeueReusableCellWithIdentifier 返回 nil 并崩溃。

关于为什么会发生这种情况的任何提示？

这是 viewDidLoad 的代码:

- (void)viewDidLoad {
if (IoUIDebug & IoUIDebugSelectorNames) {
    NSLog(@"%@ - %@", [self description], NSStringFromSelector(_cmd) );
}   

[super viewDidLoad];



    // Create an Empty Tableview and steal its Background. 
    //set our background to it
UITableView *tv = [[UITableView alloc] initWithFrame:self.view.frame style:UITableViewStyleGrouped];
UIView *backgroundView = tv.backgroundView;
[self.view addSubview:backgroundView];
[tv release];
    // CGRect backgroundFrame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
    //[backgroundView setFrame:backgroundFrame];
[self.view sendSubviewToBack:backgroundView];


saveButton.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
saveButton.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;
saveButton.titleLabel.textAlignment = UITextAlignmentCenter;
saveButton.titleLabel.lineBreakMode = UILineBreakModeCharacterWrap;

[saveButton setTitle:NSLocalizedStringFromTable(@"Save Animation Label",@"ScreenEditor",@"Save Animation Label") forState:UIControlStateNormal];    
[saveButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
saveButton.titleLabel.font = [UIFont boldSystemFontOfSize:17];

UIImage *newImage = [[UIImage imageNamed:@"BlueButtonSmall.png"] stretchableImageWithLeftCapWidth:12.0 topCapHeight:0.0];
[saveButton setBackgroundImage:newImage forState:UIControlStateNormal];

UIImage *newPressedImage = [[UIImage imageNamed:@"BlueButtonSmallPressed.png"] stretchableImageWithLeftCapWidth:12.0 topCapHeight:0.0];
[saveButton setBackgroundImage:newPressedImage forState:UIControlStateHighlighted];


    // in case the parent view draws with a custom color or gradient, use a transparent color
saveButton.backgroundColor = [UIColor clearColor];


if (UIAppDelegate.ioMainViewController.currentDeployment.readOnlyMode == NO) {                // Only setup for the long press if the deployment is editable..
    instructionLabel.text = NSLocalizedStringFromTable(@"Animation Details Instructions", @"ScreenEditor", @"");

} else {
    instructionLabel.text = NSLocalizedStringFromTable(@"Locked Message", @"Configuration",@"");
}

IoCDElementAnimation * currentAnimation = UIAppDelegate.ioMainViewController.currentElementAnimation;

if (currentAnimation) {
    newAnimation = currentAnimation;
    selectedSysCDAnimation =  currentAnimation.sysAnimation;  
    selectedIoCDTag = currentAnimation.tag;
    animationSaved = YES;

} else {
    selectedSysCDAnimation  = nil;
    selectedIoCDTag = nil;
    animationSaved = NO;
}

UINib *animCellNib = [UINib nibWithNibName:@"IoUISEAnimationDetailListingCell" bundle:nil];

[animationDetailsTableView registerNib:animCellNib forCellReuseIdentifier:@"AnimationDetailListingCell"];

    //  set our TableView Background to clear so we can see our new background
[animationDetailsTableView setBackgroundView:nil];
[animationDetailsTableView setBackgroundColor:[UIColor clearColor]];

[self refreshContents:nil];

[self setupOrientation:[[UIApplication sharedApplication] statusBarOrientation]];
[self.view setNeedsLayout];
}

在此方法中，dequeueReusableCellWithIdentifier: 返回 nil。无法找到 AnimationDetailListingCell 标识符，因为 viewDidLoad 中的 registerNib 代码尚未运行。看起来所有的 viewDidLoad 都应该在初始化 tableview 之前运行，对吧？

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
if (IoUIDebug & IoUIDebugSelectorNames) {
    NSLog(@"%@ - %@", [self description], NSStringFromSelector(_cmd) );
}
UITableViewCell *cell;

cell = [animationDetailsTableView dequeueReusableCellWithIdentifier:@"AnimationDetailListingCell"];
// cell at this point in nil!

[self configureCell:cell atIndexPath:indexPath];

return cell;
}

Answer 1

我有同样的错误。我认为这是因为调整某些按钮属性意味着需要设置 View (显然是懒惰创建的)，这意味着表需要准备好，但还没有，可能是因为它的数据源尚未连接或者其他的东西。尝试在 viewDidLoad 方法中将按钮调整移至稍后；这对我有用。