对于这个问题，这是一个非常低效的第一步，我最终将重写它。但希望这会对你有所帮助。
这样做的想法是“保证”在点击“标准”部分索引视图时获得真正的表部分索引。标准的部分索引视图应该有一个用于搜索的放大镜图标，一个用于非字母部分的井号 (#)，以及用于字母部分的字母 A 到 Z。
无论有多少实际部分或它们是由什么组成的，都会呈现此标准视图。
最终，此代码将部分视图索引映射到获取的结果控制器中实际存在的字母部分名称路径，或实际存在的非字母（数字）部分，或表头中的搜索字段。
用户只会偶尔_idxArray在每次触摸节索引时重新创建节索引映射数组（
有很多地方可以开始收紧它：sectionIndexTitleLetters例如，我可以从一开始就将静态字符串全部设为大写。不过，它在 3GS 手机上已经足够快了，所以我最近没有重新审视它。
在标题中：
static NSString *sectionIndexTitleLetters = @"abcdefghijklmnopqrstuvwxyz";
在表视图数据源的实现中：
- (NSArray *) sectionIndexTitlesForTableView:(UITableView *)tv {
if (tv != searchDisplayController.searchResultsTableView) {
NSMutableArray *_indexArray = [NSMutableArray arrayWithCapacity:([sectionIndexTitleLetters length]+2)];
[_indexArray addObject:@"{search}"];
[_indexArray addObject:@"#"];
for (unsigned int _charIdx = 0; _charIdx < [sectionIndexTitleLetters length]; _charIdx++) {
char _indexChar[2] = { toupper([sectionIndexTitleLetters characterAtIndex:_charIdx]), '\0'};
[_indexArray addObject:[NSString stringWithCString:_indexChar encoding:NSUTF8StringEncoding]];
}
return _indexArray;
}
return nil;
}
- (NSInteger) tableView:(UITableView *)tv sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
if (tv != searchDisplayController.searchResultsTableView) {
if (index == 0) {
//
// This is the search bar "section"
//
[currentTableView scrollRectToVisible:[[currentTableView tableHeaderView] bounds] animated:YES];
return -1;
}
else if (index == 1) {
//
// This is the "#" section, which covers non-alphabetic section headers (e.g. digits 0-9)
//
return 0;
}
else {
//
// This is a bit more involved because the section index array may contain indices that do not exist in the
// fetched results controller's sections->name info.
//
// What we are doing here is building a "fake-index" array that will return a real section index regardless of
// whether the section index title being touched exists or not.
//
// The fake array will be of length of the section index title array, and each index will contain an unsigned
// integer from 1 to {numOfRealSections}.
//
// The value this array returns will be "nearest" to the real section that is in the fetched results controller.
//
NSUInteger _alphabeticIndex = index-2;
unsigned int _idxArray[26];
for (unsigned int _initIdx = 0; _initIdx < [sectionIndexTitleLetters length]; _initIdx++) {
_idxArray[_initIdx] = [[fetchedResultsController sections] count] - 1;
}
unsigned int _previousChunkIdx = 0;
NSNumberFormatter *_numberFormatter = [[NSNumberFormatter alloc] init];
NSLocale *_enUSLocale = [[NSLocale alloc] initWithLocaleIdentifier: @"en_US"];
[_numberFormatter setLocale:_enUSLocale];
[_enUSLocale release];
for (unsigned int _sectionIdx = 0; _sectionIdx < [[fetchedResultsController sections] count]; _sectionIdx++) {
NSString *_sectionTitle = [[[fetchedResultsController sections] objectAtIndex:_sectionIdx] name];
if (![_numberFormatter numberFromString:_sectionTitle]) {
// what's the index of the _sectionTitle across sectionIndexTitleLetters?
for (unsigned int _titleCharIdx = 0; _titleCharIdx < [sectionIndexTitleLetters length]; _titleCharIdx++) {
NSString *_titleCharStr = [[sectionIndexTitleLetters substringWithRange:NSMakeRange(_titleCharIdx, 1)] uppercaseString];
if ([_titleCharStr isEqualToString:_sectionTitle]) {
// put a chunk of _sectionIdx into _idxArray
unsigned int _currentChunkIdx;
for (_currentChunkIdx = _previousChunkIdx; _currentChunkIdx < _titleCharIdx; _currentChunkIdx++) {
_idxArray[_currentChunkIdx] = _sectionIdx - 1;
}
_previousChunkIdx = _currentChunkIdx;
break;
}
}
}
}
[_numberFormatter release];
return (NSInteger)_idxArray[_alphabeticIndex];
}
}
return 0;
}