iOS 开发 排序问题 （好友列表，按字母排序）

iOS 开发 排序问题 （好友列表，按字母排序）

一、预备工作
①好友数据模型展示
FriendModel

@property(nonatomic,copy)NSString *photo;@property(nonatomic,copy)NSString *userName;@property(nonatomic,copy)NSString *userId;@property(nonatomic,copy)NSString *phoneNO;

我们用userName的首字母排序；
② 存放model的数组 dataSource
③存放所有首字母的数组 lettersArray
④存放首字母对应字典， nameDic 字典中内容为该字母下的model数组

二、 下面是排序方法

- (void)handleLettersArray{    NSMutableDictionary *tempDic = [[NSMutableDictionary alloc]init];    for(FriendModel *friends  in dataSource)//①、②    {        HanyuPinyinOutputFormat *formatter =  [[HanyuPinyinOutputFormat alloc] init];        formatter.caseType = CaseTypeLowercase;        formatter.vCharType = VCharTypeWithV;        formatter.toneType = ToneTypeWithoutTone;        NSString *outputPinyin=[PinyinHelper toHanyuPinyinStringWithNSString:friends.userName withHanyuPinyinOutputFormat:formatter withNSString:@""];        NSLog(@"%@",[[outputPinyin substringToIndex:1] uppercaseString]);        [tempDic setObject:friends forKey:[[outputPinyin substringToIndex:1] uppercaseString]];    }    self.lettersArray = tempDic.allKeys;//③    for (NSString *letter in self.lettersArray) {        NSLog(@"letter==%@",letter);        NSMutableArray *tempArry = [[NSMutableArray alloc] init];        for (NSInteger i = 0; i<dataSource.count; i++) {            FriendModel *friends = dataSource[i];            NSLog(@"name = %@",friends.userName);            HanyuPinyinOutputFormat *formatter =  [[HanyuPinyinOutputFormat alloc] init];            formatter.caseType = CaseTypeUppercase;            formatter.vCharType = VCharTypeWithV;            formatter.toneType = ToneTypeWithoutTone;            NSString *outputPinyin=[PinyinHelper toHanyuPinyinStringWithNSString:friends.userName withHanyuPinyinOutputFormat:formatter withNSString:@""];            NSLog(@"%@",[[outputPinyin substringToIndex:1] uppercaseString]);            if ([letter isEqualToString:[[outputPinyin substringToIndex:1] uppercaseString]]) {                [tempArry addObject:friends];            }        }        [self.nameDic setObject:tempArry forKey:letter];// ④//        NSLog(@"tempArry==%@",tempArry);    }    self.lettersArray = tempDic.allKeys;//    NSLog(@"%@",self.lettersArray);    NSComparator cmptr = ^(id obj1, id obj2){        if ([obj1 characterAtIndex:0] > [obj2 characterAtIndex:0]) {            return (NSComparisonResult)NSOrderedDescending;        }        if ([obj1 characterAtIndex:0] < [obj2 characterAtIndex:0]) {            return (NSComparisonResult)NSOrderedAscending;        }        return (NSComparisonResult)NSOrderedSame;    };    self.lettersArray = [[NSMutableArray alloc]initWithArray:[self.lettersArray sortedArrayUsingComparator:cmptr]];    NSLog(@"%@",self.lettersArray);}

三、用法
做tableView时，用letterArray确定分组数，取出key，用key从nameDic中取出该组的model。