iOS TableView : Grouping rows into sections

Question

我在表格 View 中显示一个动态的名字列表，我试图根据名字的第一个字母将它们分成几个部分...

我创建了一个数组，其中包含按字母顺序排列的字母列表

charIndex = [[NSMutableArray alloc] init];

for(int i=0; i<[appDelegate.children count]-1; i++)
{
    // get the person
    Child *aChild = [appDelegate.children objectAtIndex:i];

    // get the first letter of the first name
    NSString *firstLetter = [aChild.firstName substringToIndex:1];

    NSLog(@"first letter: %@", firstLetter);

    // if the index doesn't contain the letter
    if(![charIndex containsObject:firstLetter])
    {
        // then add it to the index
        NSLog(@"adding: %@", firstLetter);
        [charIndex addObject:firstLetter];
    }
}

我已经设置了部分的数量和标题

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // set the number of sections in the table to match the number of first letters
    return [charIndex count];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    // set the section title to the matching letter
    return [charIndex objectAtIndex:section];
}

但是我不知道应该放什么

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

}

Answer 1

您可以添加一个字典来跟踪首字母相同的人数。快速未经测试的代码:

charIndex = [[NSMutableArray alloc] init];
charCount = [[NSMutableDictionary alloc] init];

    for(int i=0; i<[appDelegate.children count]-1; i++)
    {
        // get the person
        Child *aChild = [appDelegate.children objectAtIndex:i];

        // get the first letter of the first name
        NSString *firstLetter = [aChild.firstName substringToIndex:1];

        NSLog(@"first letter: %@", firstLetter);

        // if the index doesn't contain the letter
        if(![charIndex containsObject:firstLetter])
        {
            // then add it to the index
            NSLog(@"adding: %@", firstLetter);
            [charIndex addObject:firstLetter];
            [charCount setObject:[NSNumber numberWithInt:1] forKey:firstLetter];
        }
        [charCount setObject:[NSNumber numberWithInt:[[charCount objectForKey:firstLetter] intValue] + 1] forKey:firstLetter];
    }

然后在:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    [charCount objectForKey:[charIndex objectAtIndex:section]];
}