UITableViewCellAccessibilityElement 发布在选项卡切换时崩溃

Posted 2023-03-05

【中文标题】UITableViewCellAccessibilityElement 发布在选项卡切换时崩溃

【英文标题】：UITableViewCellAccessibilityElement release Crashes on Tab Switching

【发布时间】：2012-10-18 13:14:33

【问题描述】：

我正在为 ios（5 以上）开发一个选项卡式应用程序。 在 3 个选项卡中的 2 个选项卡之间进行几次切换后，我的应用程序在模拟器中遇到崩溃，这两个选项卡都包含表（以及其他一些 - 这里可能不相关的东西）。以下是单元格创建的重要部分和错误代码。

崩溃发生在（每次不同的）更改次数之后，并且总是在访问选项卡 2 时发生。

注意我正在使用 ARC。

* UPDATE* 该问题仅出现在 iOS 6 上。以前的版本不受影响。它可能依赖于一些被调用的线程代码，如下所示：

if (!self.progressBackground) 
        self.progressBackground = [[UIView alloc]initWithFrame:CGRectMake(100, 260, 120, 120)];
        [self.progressBackground setBackgroundColor:[UIColor blackColor]];
        [[self.progressBackground layer]setCornerRadius:15];
        UILabel *progressText = [[UILabel alloc]initWithFrame:CGRectMake(0, 80, 120, 30)];
        UIFont *fontName = [UIFont fontWithName:@"Helvetica" size:14.0];
        [progressText setFont:fontName];
        [progressText setText:@"Updating Tags"];
        [progressText setTextColor:[UIColor whiteColor]];
        [progressText setTextAlignment:UITextAlignmentCenter];
        [progressText setBackgroundColor:[UIColor clearColor]];
        [self.progressBackground addSubview:progressText];
        [self.progressBackground setAlpha:.6];                   
    
    if (!self.progressView) 
        self.progressView = [[UIActivityIndicatorView alloc]initWithFrame:self.progressBackground.frame];
        [self.progressView setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhiteLarge];
    
    [self.view addSubview:self.progressBackground];
    [self.view addSubview:self.progressView];
    [self.progressView  startAnimating];

    [NSThread detachNewThreadSelector:@selector(initializeCategoriesArray) toTarget:self withObject:nil]; 

'initializeCategoriesArray' 方法看起来像这样：

-(void)initializeCategoriesArray

if (!self.categoryArchive) 
    self.categoryArchive = [[NSMutableArray alloc]init];
 

//set the right month' expenses
self.currentMonthExpenses = (NSMutableArray*)[self.dataHandler fetchAllExpensesForMonth:[NSNumber numberWithInteger:self.currentMonthNumber ]];


// check if expenses exist at all

if (self.currentMonthExpenses.count == 0) 
    [self.categoryArchive removeAllObjects];
    [self.categoriesTable reloadData];
    [self.progressView performSelectorOnMainThread:@selector(stopAnimating) withObject:nil waitUntilDone:YES];
    [self.progressView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
    [self.progressBackground performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
    return;




// sort out month Expenses
NSMutableArray *dayTypeExpenses = [[NSMutableArray alloc]init];
for (Expense *exp in self.currentMonthExpenses) 
    if (exp.expenseType.boolValue == NO) 
        [dayTypeExpenses addObject:exp];
    



// check if dayExpenses exist
if (dayTypeExpenses.count == 0) 
    [self.categoryArchive removeAllObjects];
    [self.categoriesTable reloadData];
    [self.progressView performSelectorOnMainThread:@selector(stopAnimating) withObject:nil waitUntilDone:YES];
    [self.progressView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
    [self.progressBackground performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
    return;


// create Dictionary holding all DayExpenses under their STRING AS KEY
NSMutableDictionary *tempDict = [[NSMutableDictionary alloc]init];
for (Expense *exp in dayTypeExpenses) 

    NSMutableArray *temp = [tempDict objectForKey:exp.name];
    if (temp == nil) 
        NSMutableArray *tempArray = [[NSMutableArray alloc]init];
        [tempDict setValue:tempArray forKey:exp.name];
    
    [[tempDict objectForKey:exp.name]addObject:exp];


// create temporary (unsorted) array of Categories
NSMutableArray *tempCatArray = [[NSMutableArray alloc]init];
for (NSMutableArray *expArray in [tempDict allValues]) 
    double totValue = 0;
    NSInteger count = 0;
    double average = 0;
    CGFloat percentage = 0;
    for (Expense* exp in expArray) 
        count++;
        totValue = totValue+exp.value.doubleValue;
    
    average = totValue/count;
    percentage = totValue/self.spentCurrentMonth;
    Category *newCategory = [[Category alloc]init];
    [newCategory setTotalValue:totValue];
    [newCategory setName:[[expArray objectAtIndex:0]name]];
    [newCategory setNumberOfExpenses:count];
    [newCategory setAverageValue:average];
    [newCategory setPercentOfBudgetInFloat:fabs(percentage)];

    [tempCatArray addObject:newCategory];


// sort tempArray
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc]initWithKey:@"totalValue" ascending:YES];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];
self.categoryArchive = [[tempCatArray sortedArrayUsingDescriptors:sortDescriptors]mutableCopy];

// find normfactor


CGFloat normFactor = fabs(1.0/[[self.categoryArchive objectAtIndex:0] percentOfBudgetInFloat]);

for (Category *cat in self.categoryArchive) 
    if (cat.name.length == 0) 
        cat.name = @"Uncategorized";
    
    if (cat.percentOfBudgetInFloat >= 1) 
        cat.percentOfBudgetInFloat = 1;
    
    cat.percentOfBudgetInFloat = cat.percentOfBudgetInFloat*normFactor;



// reload
[self.categoriesTable reloadData];

[self.progressView performSelectorOnMainThread:@selector(stopAnimating) withObject:nil waitUntilDone:YES];
[self.progressView performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];
[self.progressBackground performSelectorOnMainThread:@selector(removeFromSuperview) withObject:nil waitUntilDone:YES];

标签 1：

TableView, each cell contains 2 labels 1 button

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
static NSString *CellIdentifier = @"dayCell";    
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell == nil) 
    UIFont *subjectFont = [UIFont fontWithName:@"Helvetica" size:14.0];
    UIFont *valueFont = [UIFont fontWithName:@"Helvetica-Bold" size:14.0];

    cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
    [cell.textLabel removeFromSuperview];


    // Cell Look
    UIImageView *backgroundImg = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"cell" ]];
    [cell setBackgroundView:backgroundImg];

    // Subjectlabel
    UILabel *subjectLabel = [[UILabel alloc]initWithFrame:CGRectMake(30, 15, 160, 20)];
    //...

    // ValueLabel
    UILabel *valueLabel = [[UILabel alloc]initWithFrame:CGRectMake(160, 15, 90, 20)];
    //...


    // Deletion Button
    UIButton *delButton = [[UIButton alloc]initWithFrame:CGRectMake(255, 0, 50, 50)];
    [delButton setBackgroundColor:[UIColor clearColor]];
    [delButton setImage:[UIImage imageNamed:@"delButt" ] forState:UIControlStateNormal ];
    delButton.tag = 1002;
    [cell addSubview:delButton];

//...

UIButton *delButton = (UIButton*)[cell viewWithTag:1002];
[delButton addTarget:self action:@selector(deleteRow:) forControlEvents:UIControlEventTouchUpInside];

//...
return cell;

标签 2：

TableView, each cell contains 2 labels, 1 rectangular UIView

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
static NSString *CellIdentifier = @"thisMonthCell";


UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

if (cell == nil) 
    UIFont *subjectFont = [UIFont fontWithName:@"Helvetica" size:14.0];
    UIFont *valueFont = [UIFont fontWithName:@"Helvetica-Bold" size:16.0];

    cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier];
    [cell.textLabel removeFromSuperview];

    // BarGraph for this Cell
    UIView *barProgress = [[UIView alloc]initWithFrame:CGRectMake(20, 1, 1, 37)];
    [barProgress setBackgroundColor:[self goldBarColor]];
    [barProgress setAlpha:.5];
    barProgress.tag = 1000;
    [cell addSubview:barProgress];





Category *cellCategory = [self.categoryArchive objectAtIndex:indexPath.row];

UIView *progressBar = (UIView *)[cell viewWithTag:1000];
[progressBar setFrame:CGRectMake(progressBar.frame.origin.x, progressBar.frame.origin.y, cellCategory.percentOfBudgetInFloat*280, progressBar.frame.size.height)];

//...


return cell;

---

崩溃时的错误代码如下：

2012-10-18 14:57:13.218 DailyBudget[4714:c07] * -[UITableViewCellAccessibilityElement release]：消息发送到已释放实例 0x7571630 dlopen（/Applications/Xcode.app/Contents/PlugIns/DebuggerFoundation.ideplugin/Contents/Resources/DebuggerIntrospectionSupport.dylib，0x00000002） dyld：加载：/Applications/Xcode.app/Contents/PlugIns/DebuggerFoundation.ideplugin/Contents/Resources/DebuggerIntrospectionSupport.dylib

---

问题仅出现在模拟器中，而不出现在真实设备上（均为 iOS 6.0）

任何想法可能是什么问题？

【参考方案1】：

编辑：

实际问题是从主线程更新 UI。阅读 cmets 了解详情。

--- 原始答案---

我建议您使用自定义单元格，而不是尝试以编程方式更改内置的 Apple tableviewcell。文档有一些很好的例子来说明如何做到这一点。如果你有故事板，那真的很容易。

我的猜测是你弄乱了 tableview 单元格的对象（文本标签 -- 附件视图连接）中的预期保留计数发生了一些事情，并且 arc 没有捕捉到你的 removeFromSuperview 魔法。

【讨论】：

这不是问题所在。似乎遗留线程代码使它跳跃。我删除了背景线程并现在在主线程中进行计算 - 奖励仍然存在，因为我真的不知道为什么这是一个问题；）

所有 ui 代码都需要在主线程上完成。对不起，我错过了。

只有一行 [_tableView reloadData]，所以这是唯一的问题？

应该是。打开 XCode，打开文档并粘贴这个 threads and your user interface 这个小简介应该比我能更好地解释它。 :-)

【参考方案2】：

UIKit 可能会尝试发布一些它内部预计不需要发布的东西。尝试在这两个实现中注释掉 [cell.textLabel removeFromSuperview]; 并将其替换为 cell.textLabel.hidden = YES ，这很可能会阻止这次崩溃。

【讨论】：

感谢输入，遗憾的是这并没有解决问题:(