iOS错误"请求无效部分的矩形"是什么意思？

Question

谷歌没有发现此错误消息的帖子.我在iOS 5中尝试更新UITableView.虽然确切的代码有点折磨,但这正是我对表和具有表数据的NSMutableArray所做的.调用是通过performSelectorOnMainThread调用从主线程进行的,如下面的代码片段所示.NSMutableArray节是一个数组数组,每个数组表示一个节,其中这些辅助数组是NSStrings,其中包含表中显示的文本.

从主线程:

[table performSelectorOnMainThread: @selector(beginUpdates) withObject: nil waitUntilDone: YES];

从另一个performSelectorOnMainThread调用的主代码:

// Make sure the requested section exists.
if (sections == nil)
    sections = [[NSMutableArray alloc] init];
while (section >= [sections count]) {
    NSMutableArray *newArray = [[NSMutableArray alloc] init];
    [sections addObject: newArray];

    [table insertSections: [NSIndexSet indexSetWithIndex: [sections count]] 
                                        withRowAnimation: UITableViewRowAnimationNone];
}

// Insert the new row in the section.
NSMutableArray *rowArray = [sections objectAtIndex: section];
if (row > [rowArray count])
    row = [rowArray count];
[rowArray insertObject: cellString atIndex: row];

[table insertRowsAtIndexPaths: [NSArray arrayWithObject: [NSIndexPath indexPathForRow: row inSection: section]]
             withRowAnimation: UITableViewRowAnimationNone];

在上面的代码完成后调用:

[table performSelectorOnMainThread: @selector(endUpdates) withObject: nil waitUntilDone: YES];

此调用endUpdates时发生错误.确切的错误消息是:

2012-01-04 14:28:10.951 myApp[2183:fb03] *** Assertion failure in -[UITableViewRowData rectForSection:], /SourceCache/UIKit_Sim/UIKit-1912.3/UITableViewRowData.m:1449
2012-01-04 14:28:10.953 myApp[2183:fb03] *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'request for rect of invalid section (1)'
*** First throw call stack:
(0x1833052 0x1d94d0a 0x17dba78 0x11472db 0x99c832 0xa1b93b 0xa1b886 0xa1b451 0xa28134 0x8458e1 0x842602 0x84d211 0x84d23f 0x1834e72 0x10d69ef 0x180797f 0x176ab73 0x176a454 0x1769db4 0x1769ccb 0x33b6879 0x33b693e 0x7bea9b 0x1fad 0x1f25)
terminate called throwing an exception

这个错误意味着什么,我需要改变什么以避免它？

Answer 1

看起来您的代码正在尝试使用表中不存在的部分.

由于NSArrays是零索引的,因此索引值count将超出数组的范围.在indexSetWithIndex:此处使用时,您应该从计数中减去一个:

[table insertSections: [NSIndexSet indexSetWithIndex: [sections count]-1] 
                                    withRowAnimation: UITableViewRowAnimationNone];