Question

我正在尝试对我的Facebook好友列表进行排序，以实现索引表视图，就像在Facebook Messenger中找到的那样。

我最初尝试使用UILocalizedIndexedCollation，但我被困在“collationStringSelector”上，因为我的dataSource数组是id<"FBGraphUser">个对象，因此我没有可用于选择器的属性。关于如何实现这一点的任何想法（它不必使用这种方法，我对任何事情都开放！）？

-(NSArray *)partitionObjects:(NSArray *)array collationStringSelector:(SEL)selector {
    UILocalizedIndexedCollation *collation = [UILocalizedIndexedCollation currentCollation];

    NSInteger sectionCount = [[collation sectionTitles] count]; // section count is take from sectionTitles and not sectionIndexTitles
    NSMutableArray *unsortedSections = [NSMutableArray arrayWithCapacity:sectionCount];

    // create an array to hold the data for each section
    for (int i = 0; i < sectionCount; i++) {
        [unsortedSections addObject:[NSMutableArray array]];
    }

    // put each object into a section
    for (id object in array) {
        NSInteger index = [collation sectionForObject:object collationStringSelector:selector];
        [[unsortedSections objectAtIndex:index] addObject:object];
    }

    NSMutableArray *sections = [NSMutableArray arrayWithCapacity:sectionCount];

    // sort each section
    for (NSMutableArray *section in unsortedSections) {
        [sections addObject:[collation sortedArrayFromArray:section collationStringSelector:selector]];
    }

    return sections;
}

Answer 1

这是我前段时间创建的UITableViewController的子类，用于制作索引表视图。我使用它作为控制台的基类，其表视图出现在屏幕上，因此它是一个可重用的类，可以完成创建表的艰苦工作。您可以按原样使用它，但我没有尝试使它太普遍。我传入一个简单的自定义对象数组（我的对象只有名字和姓氏），这个类创建了部分和索引。所以这是代码，

.h

@interface RDIndexedTableController : UITableViewController

@property (strong,nonatomic) NSArray *inputArray;
@property (strong,nonatomic) NSString *sectionKey;
@property (strong,nonatomic) NSString *secondarySortKey;
@property (nonatomic, retain) NSMutableArray *sectionsArray;
@property (nonatomic, retain) UILocalizedIndexedCollation *collation;

-(void)convertArray:(NSArray *)input usingSectionKey:(NSString *)key secondarySortKey:(NSString *)sorter;
@end

.m

@interface RDIndexedTableController ()
@property (strong,nonatomic) NSMutableArray *firstLetterArray;
@end

@implementation RDIndexedTableController


-(void)convertArray:(NSArray *)input usingSectionKey:(NSString *)key secondarySortKey:(NSString *)sorter {
    self.inputArray = input;
    self.sectionKey = key;
    self.secondarySortKey = sorter;
    [self configureSections];
}


- (void)configureSections {

    self.collation = [UILocalizedIndexedCollation currentCollation];
    NSInteger sectionTitlesCount = [[self.collation sectionTitles] count];
    NSMutableArray *newSectionsArray = [[NSMutableArray alloc] initWithCapacity:sectionTitlesCount];

    for (int index = 0; index < sectionTitlesCount; index++) {
        NSMutableArray *array = [[NSMutableArray alloc] init];
        [newSectionsArray addObject:array];
    }

    for (id obj in self.inputArray) {
        NSInteger sectionNumber = [self.collation.sectionTitles indexOfObject:[[obj valueForKey:self.sectionKey] substringToIndex:1]];

        NSMutableArray *sectionForObjects = [newSectionsArray objectAtIndex:sectionNumber];
        [sectionForObjects addObject:obj];
    }

    for (int index = 0; index < sectionTitlesCount; index++) {

        NSMutableArray *objectArrayForSection = [newSectionsArray objectAtIndex:index];
        NSArray *firstSortedObjectArrayForSection = [self.collation sortedArrayFromArray:objectArrayForSection collationStringSelector:NSSelectorFromString(self.secondarySortKey)];
        NSArray *sortedObjectArrayForSection = [self.collation sortedArrayFromArray:firstSortedObjectArrayForSection collationStringSelector:NSSelectorFromString(self.sectionKey)];
        [newSectionsArray replaceObjectAtIndex:index withObject:sortedObjectArrayForSection];
    }
    self.sectionsArray = newSectionsArray;
}



- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return self.collation.sectionTitles.count;
}



- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    NSArray *objectsInSection = [self.sectionsArray objectAtIndex:section];
    return objectsInSection.count;
}



- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    return self.collation.sectionTitles[section];
}


-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
    if ([[self.sectionsArray objectAtIndex:section] count] == 0) {
        return 0;
    }else{
        return 30;
    }
}



- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
    return @[@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z"];
}



- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
    return [self.collation sectionForSectionIndexTitleAtIndex:index];
}

在应用程序中显示的表格视图控制器中，我只需要这么少量的代码来填充表格，

 -(void)viewDidLoad {
    [super viewDidLoad];
    [self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:@"Cell"];
    NSMutableArray *mut = [NSMutableArray new];
    // create the Person objects and add them to the array here

    [self convertArray:mut usingSectionKey:@"lastName" secondarySortKey:@"firstName"];
    [self.tableView reloadData];
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    NSString *first = [self.sectionsArray[indexPath.section][indexPath.row] valueForKey:@"firstName"];
    NSString *last = [self.sectionsArray[indexPath.section][indexPath.row] valueForKey:@"lastName"];
    cell.textLabel.text = [NSString stringWithFormat:@"%@ %@",first,last];
    return cell;
}

Facebook好友的索引表视图

1 个答案: