如何按字母顺序将NSArray拆分为UITableView部分

Question

我在使用带有节标题的索引表时遇到问题.目前我在右侧有索引,我有正确显示的部分标题,标题只显示该部分内是否有数据.

我遇到的问题是将NSArray分成几部分,这样我就可以正确计算numberOfRowsInSections.目前我有正确数量的部分显示正确的标题,但所有数据都在每个部分,而不是根据名称的第一个字母拆分.

以下是目前的截图:

所有数据都分为每个部分,每行5行.部分(3)的数量是正确的

我的代码如下:

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    return [firstLetterArray objectAtIndex:section];
}

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView
{

    NSMutableSet *mySet = [[NSMutableSet alloc] init];

    BRConnection *connection = nil;
    NSMutableArray *firstNames = [[NSMutableArray alloc] init];
    for (connection in _connections)
    {
        [firstNames addObject:connection.firstName];
    }
    firstNamesArray = firstNames;
    NSLog(@"%@", firstNamesArray);
    for ( NSString *s in firstNames)
    {
        if ([s length] > 0)
            [mySet addObject:[s substringToIndex:1]];
    }

    NSArray *indexArray = [[mySet allObjects] sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];

    firstLetterArray = indexArray;

    return [[UILocalizedIndexedCollation currentCollation] sectionIndexTitles];
}

- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {

    if ([title isEqualToString:@"{search}"])
    {
        [tableView setContentOffset:CGPointMake(0.0, -tableView.contentInset.top)];
        return [[UILocalizedIndexedCollation currentCollation] sectionForSectionIndexTitleAtIndex:index];
    }
    return [[UILocalizedIndexedCollation currentCollation] sectionForSectionIndexTitleAtIndex:index];
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"ConnectionCell"];

    // Display connection in the table cell
    BRConnection *connection = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        connection = [searchResults objectAtIndex:indexPath.row];
    } else {
        connection = [_connections objectAtIndex:indexPath.row];
    }

    cell.textLabel.text = connection.fullName;
    cell.textLabel.font = [UIFont fontWithName:@"TitilliumText25L-400wt" size:18];
    cell.detailTextLabel.text = connection.company;
    cell.detailTextLabel.font = [UIFont fontWithName:@"TitilliumText25L-400wt" size:12];

    return cell;
}


- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    NSUInteger sections = [firstLetterArray count];
    return sections;

}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        return [searchResults count];

    } else {
        return [_connections count];
    }
}

任何帮助将不胜感激,我似乎无法将NSArray conenctions分成一个按字母顺序排列的列表,以获得一个部分中的正确行.在此先感谢大家!

Answer 1

您在哪里以及如何填充_connections？您正在使用该数组来确定每个部分的行数并填充这些行,但是_connections返回整个列表.您需要_connections按字母顺序拆分数据.

比如,也许你可以使用NSMutableArray的NSMutableArray由字母s组数据.由于您似乎已经知道如何按字母顺序排序,现在您只需要识别每个字符串的第一个字符即可正确分组.为此,请尝试:

NSString *currentPrefix;

// Store sortedConnections as a class variable (as you've done with _connections)
// so you can access it to populate your table
sortedConnections = [[NSMutableArray alloc] init];

// Go through each connection (already ordered alphabetically)
for (BRConnection *connection in _connections) {

    // Find the first letter of the current connection
    NSString *firstLetter = [connection.fullName substringToIndex:1];

    // If the last connection's prefix (stored in currentPrefix) is equal
    // to the current first letter, just add the connection to the final
    // array already in sortedConnections
    if ([currentPrefix isEqualToString:firstLetter]) {
        [[sortedConnected lastObject] addObject:connection];
    }

    // Else create a new array in sortedConnections to contain connections starting
    // with this current connection's letter.
    else {
        NSMutableArray *newArray = [[NSMutableArray alloc] initWithObject:connection];
        [sortedConnections addObject:newArray];
    }

    // To mark this latest array's prefix, set currentPrefix to contain firstLetter
    currentPrefix = firstLetter;
}

(即使第一个字母未知,这种方式也会有效.)

然后要获取每个部分的行数,请使用[sortedConnections objectAtIndex:section]而不是_connections:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        return [[sortedSearchResults objectAtIndex:section] count]; // hypothetically
    } else {
        return [[sortedConnections objectAtIndex:section] count];
    }
}

并填充表基本上使用相同的方法[sortedConnections objectAtIndex:indexPath.section]:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"ConnectionCell"];

    // Display connection in the table cell
    BRConnection *connection = nil;
    if (tableView == self.searchDisplayController.searchResultsTableView) {
        connection = [[sortedSearchResults objectAtIndex:indexPath.section] objectAtIndex:indexPath.row]; // hypothetically
    } else {
        connection = [[sortedConnections objectAtIndex:indexPath.section] objectAtIndex:indexPath.row];
    }

    cell.textLabel.text = connection.fullName;
    cell.textLabel.font = [UIFont fontWithName:@"TitilliumText25L-400wt" size:18];
    cell.detailTextLabel.text = connection.company;
    cell.detailTextLabel.font = [UIFont fontWithName:@"TitilliumText25L-400wt" size:12];

    return cell;
}

Answer 2

希望能帮助你,我不知道是否是最好的方法,但它的工作原理=)

NSArray *names = @[@"Ana Carolina", @"Ana carolina", @"Ana luiza", @"leonardo", @"fernanda", @"Leonardo Cavalcante"];

NSMutableSet *firstCharacters = [NSMutableSet setWithCapacity:0];
for( NSString*string in names ){
    [firstCharacters addObject:[[string substringToIndex:1] uppercaseString]];
}
NSArray *allLetters = [[firstCharacters allObjects] sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];
int indexLetter = 0;
NSMutableArray *separeNamesByLetters = [NSMutableArray new];



for (NSString *letter in allLetters) {
    NSMutableDictionary*userBegeinsWith = [NSMutableDictionary new];
    [userBegeinsWith setObject:letter forKey:@"letter"];
    NSMutableArray *groupNameByLetters = [NSMutableArray new];
    NSString *compareLetter1 = [NSString stringWithFormat:@"%@", allLetters[indexLetter]];
    for (NSString*friendName in names) {
        NSString *compareLetter2 = [[friendName substringToIndex:1] uppercaseString];

        if ( [compareLetter1 isEqualToString:compareLetter2] ) {
            [groupNameByLetters addObject:friendName];
        }
    }
    indexLetter++;
    [userBegeinsWith setObject:groupNameByLetters forKey:@"list"];
    [separeNamesByLetters addObject: userBegeinsWith];
}



NSLog(@"%@", separeNamesByLetters);

输出:

 (
        {
        letter = A;
        list =         (
            "ana carolina",
            "Ana carolina",
            "Ana luiza"
        );
    },
        {
        letter = F;
        list =         (
            fernanda
        );
    },
        {
        letter = L;
        list =         (
            leonardo,
            "Leonardo Cavalcante"

        )
    }
)