iphone - 使 UITableView 可按索引滚动

Question

我正在尝试创建一个 UITableView 索引以更快地滚动大型 UITableView，我在右侧显示了索引，但是当我尝试使用它滚动时, 它不起作用..

我想知道我是否遗漏了什么，所以我想知道是否还有其他事情我必须做，或者类似的事情。

#pragma - TableView Index Scrolling

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

    if(searching)
        return nil;

    NSMutableArray *tempArray = [[NSMutableArray alloc] init];
    [tempArray addObject:@"A"];
    [tempArray addObject:@"B"];
    [tempArray addObject:@"C"];
    [tempArray addObject:@"D"];
    [tempArray addObject:@"E"];
    [tempArray addObject:@"F"];
    [tempArray addObject:@"G"];
    [tempArray addObject:@"H"];
    [tempArray addObject:@"I"];
    [tempArray addObject:@"J"];
    [tempArray addObject:@"K"];
    [tempArray addObject:@"L"];
    [tempArray addObject:@"M"];
    [tempArray addObject:@"N"];
    [tempArray addObject:@"O"];
    [tempArray addObject:@"P"];
    [tempArray addObject:@"Q"];
    [tempArray addObject:@"R"];
    [tempArray addObject:@"S"];
    [tempArray addObject:@"T"];
    [tempArray addObject:@"U"];
    [tempArray addObject:@"V"];
    [tempArray addObject:@"W"];
    [tempArray addObject:@"Y"];
    [tempArray addObject:@"X"];
    [tempArray addObject:@"Z"];

    return tempArray;
}

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

    if(searching)
        return -1;

    return index % 2;
}

Answer 1

你可以用这个

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

它告诉表格哪个部分对应于部分标题/索引(例如“B”，1))

此方法用于返回与标题对应的部分。但是您想根据这些标题滚动单个部分的行。所以请按照以下步骤操作:

1. 创建全局数组意味着在.h文件中声明它

   NSMutableArray *alphabetsArray;
   NSMutableArray *dataArray; //--This contain your cell value i.e. Honda,Mazda--//
   

2. 在 viewDidLoad 方法中定义它，如下所示，然后从 UITableView 方法返回它..

   alphabetsArray = [[NSMutableArray alloc] init];
   [alphabetsArray addObject:@"A"];
   [alphabetsArray addObject:@"B"];
   [alphabetsArray addObject:@"C"];
   [alphabetsArray addObject:@"D"];
   [alphabetsArray addObject:@"E"];
   [alphabetsArray addObject:@"F"];
   [alphabetsArray addObject:@"G"];
   [alphabetsArray addObject:@"H"];
   [alphabetsArray addObject:@"I"];
   [alphabetsArray addObject:@"J"];
   [alphabetsArray addObject:@"K"];
   [alphabetsArray addObject:@"L"];
   [alphabetsArray addObject:@"M"];
   [alphabetsArray addObject:@"N"];
   [alphabetsArray addObject:@"O"];
   [alphabetsArray addObject:@"P"];
   [alphabetsArray addObject:@"Q"];
   [alphabetsArray addObject:@"R"];
   [alphabetsArray addObject:@"S"];
   [alphabetsArray addObject:@"T"];
   [alphabetsArray addObject:@"U"];
   [alphabetsArray addObject:@"V"];
   [alphabetsArray addObject:@"W"];
   [alphabetsArray addObject:@"Y"];
   [alphabetsArray addObject:@"X"];
   [alphabetsArray addObject:@"Z"];
   

   [Note: You can also create alphabetsArray with dynamic contains according to your dataArray. For this follow How we can create dynamic section index titles array at below]

3. 现在使用上面提到的方法获取标题

   - (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
       return alphabetsArray;
   }
   

4. 编写滚动 UITableView 的逻辑

   - (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
       for (int i = 0; i< [dataArray count]; i++) {
           // Here you return the name i.e. Honda,Mazda 
           // and match the title for first letter of name
           // and move to that row corresponding to that indexpath as below
           NSString *letterString = [[dataArray objectAtIndex:i] substringToIndex:1];
           if ([letterString isEqualToString:title]) {
               [tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];
               break;
           }
       }
       return -1;
   }
   

****我们如何创建动态章节索引标题数组****

1. 让我们假设 dataArray 是这样的

   [@"Honda",@"Maruti",@"Mazda",@"Toyota",.....]  
   

2. 如下创建动态章节索引标题数组的方法

   - (void)createAlphabetArray;
   

3. 如下实现createAlphabetArray方法

   #pragma mark - Create Alphabet Array
   - (void)createAlphabetArray {
       NSMutableArray *tempFirstLetterArray = [[NSMutableArray alloc] init];
       for (int i = 0; i < [dataArray count]; i++) {
           NSString *letterString = [[dataArray objectAtIndex:i] substringToIndex:1];
           if (![tempFirstLetterArray containsObject:letterString]) {
               [tempFirstLetterArray addObject:letterString];
           }
       }
       alphabetsArray = tempFirstLetterArray;
       [tempFirstLetterArray release];
   }
   

4. 现在只要你想改变 alphabetsArray 包含的任何地方就可以调用它

   [self createAlphabetArray]; 
   

现在您可以根据您的 dataArray 内容动态创建动态章节索引标题数组。