iOS基于UITableView实现多层展开与收起

//每个目录的数据结构如下：
@interface OpenTest : NSObject
@property (copy, nonatomic) NSString *title;  //非首层展示的标题
@property (assign, nonatomic) NSInteger level; //决定偏移量大小
@property (copy, nonatomic) NSString *openUrl; //最后一层跳转的规则
@property (copy, nonatomic) NSMutableArray *detailArray; //下一层的数据
@property (assign, nonatomic) BOOL isOpen;    //是否要展开
@property (copy, nonatomic) NSString *imageName; //首层的图片
@end 

#import "OpenTest.h"
@implementation OpenTest
- (instancetype)init {
  self = [super init];
  if (self) {
    [OpenTest mj_setupObjectClassInArray:^NSDictionary *{
      return @{
           @"detailArray" : [OpenTest class]
           };
    }];
  }
  return self;
}
@end

- (void)initData {
_dataArray = [NSMutableArray new];
_resultArray = [NSMutableArray new];

NSMutableArray *secondArray1 = [NSMutableArray new];
NSMutableArray *threeArray1 = [NSMutableArray new];
NSMutableArray *fourArray1 = [NSMutableArray new];

NSArray *FirstTitleArray = @[@"FirstTitle1", @"FirstTitle2", @"FirstTitle3", @"FirstTitle4", @"FirstTitle5", @"FirstTitle6", @"FirstTitle7", @"FirstTitle8", @"FirstTitle9", @"FirstTitle10"];
NSArray *SecondTitleArray = @[@"SecondTitle1", @"SecondTitle2", @"SecondTitle3"];
NSArray *ThreeTitleArray = @[@"ThreeTitle1", @"ThreeTitle2", @"ThreeTitle3", @"ThreeTitle4"];
NSArray *FourTitleArray = @[@"FourTitle1", @"FourTitle2", @"FourTitle3"];
NSArray *imageArray = @[@"scroller1", @"scroller2", @"scroller3", @"scroller4", @"scroller5", @"scroller6", @"scroller7", @"scroller8", @"scroller9", @"scroller10"];

//第四层数据
for (int i = 0; i < FourTitleArray.count; i++) {
  OpenTest *model = [[OpenTest alloc] init];
  model.title = FourTitleArray[i];
  model.level = 3;
  model.isOpen = NO;

  [fourArray1 addObject:model];
}

//第三层数据
for (int i = 0; i < ThreeTitleArray.count; i++) {
  OpenTest *model = [[OpenTest alloc] init];
  model.title = ThreeTitleArray[i];
  model.level = 2;
  model.isOpen = NO;
  model.detailArray = fourArray1;

  [threeArray1 addObject:model];
}

//第二层数据
for (int i = 0; i < SecondTitleArray.count; i++) {
  OpenTest *model = [[OpenTest alloc] init];
  model.title = SecondTitleArray[i];
  model.level = 1;
  model.isOpen = NO;
  model.detailArray = [threeArray1 mutableCopy];

  [secondArray1 addObject:model];
}

//第一层数据
for (int i = 0; i < FirstTitleArray.count; i++) {
  OpenTest *model = [[OpenTest alloc] init];
  model.title = FirstTitleArray[i];
  model.level = 0;
  model.isOpen = NO;
  model.detailArray = [secondArray1 mutableCopy];
  model.imageName = imageArray[i];

  [_dataArray addObject:model];
}

//处理源数据，获得展示数组_resultArray
[self dealWithDataArray:_dataArray];
}

/**
 将源数据数组处理成要展示的一维数组，最开始是展示首层的所有的数据
 @param dataArray 源数据数组
 */
- (void)dealWithDataArray:(NSMutableArray *)dataArray {
for (OpenTest *model in dataArray) {
  [_resultArray addObject:model];

  if (model.isOpen && model.detailArray.count > 0) {
    [self dealWithDataArray:model.detailArray];
  }
}
}

/**
 在指定位置插入要展示的数据
 @param dataArray 数据数组
 @param row    需要插入的数组下标
 */
- (void)addObjectWithDataArray:(NSMutableArray *)dataArray row:(NSInteger)row {
for (int i = 0; i < dataArray.count; i++) {
  OpenTest *model = dataArray[i];
  model.isOpen = NO;
  [_resultArray insertObject:model atIndex:row];
  row += 1;
}
}

/**
 删除要收起的数据
 @param dataArray 数据
 @param count   统计删除数据的个数
 @return 删除数据的个数
 */
- (CGFloat)deleteObjectWithDataArray:(NSMutableArray *)dataArray count:(NSInteger)count {
for (OpenTest *model in dataArray) {
  count += 1;

  if (model.isOpen && model.detailArray.count > 0) {
    count = [self deleteObjectWithDataArray:model.detailArray count:count];
  }

  model.isOpen = NO;

  [_resultArray removeObject:model];
}

return count;
}

/**
 与点击同一层的数据比较，然后删除要收起的数据和插入要展开的数据
 @param model 点击的cell对应的model
 @param row  点击的在tableview的indexPath.row,也对应_resultArray的下标
 */
- (void)compareSameLevelWithModel:(OpenTest *)model row:(NSInteger)row {
NSInteger count = 0;
NSInteger index = 0;  //需要收起的起始位置
//如果直接用_resultArray，在for循环为完成之前，_resultArray会发生改变，使程序崩溃。
NSMutableArray *copyArray = [_resultArray mutableCopy];

for (int i = 0; i < copyArray.count; i++) {
  OpenTest *openModel = copyArray[i];
  if (openModel.level == model.level) {
    //同一个层次的比较
    if (openModel.isOpen) {
      //删除openModel所有的下一层
      count = [self deleteObjectWithDataArray:openModel.detailArray count:count];
      index = i;
      openModel.isOpen = NO;
      break;
    }
  }
}

//插入的位置在删除的位置的后面，则需要减去删除的数量。
if (row > index && row > count) {
  row -= count;
}

[self addObjectWithDataArray:model.detailArray row:row + 1];
}

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];

  if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"Cell"];
    cell.selectionStyle = UITableViewCellSelectionStyleNone;

    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(15, 0, UI_SCREEN_WIDTH / 2, 32)];
    label.font = [UIFont systemFontOfSize:14];
    label.tag = LabelTag;

    [cell.contentView addSubview:label];
  }

  for (UIView *view in cell.contentView.subviews) {
    if (view.tag == LabelTag) {
      ((UILabel *)view).text = model.title;
      ((UILabel *)view).frame = CGRectMake(15 + (model.level - 1) * SpaceWidth , 0, UI_SCREEN_WIDTH / 2, 32);
    }
  }

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSInteger row = indexPath.row;
OpenTest *model = _resultArray[row];

if (model.isOpen) {
  //原来是展开的，现在要收起,则删除model.detailArray存储的数据
  [self deleteObjectWithDataArray:model.detailArray count:0];
}
else {
  if (model.detailArray.count > 0) {
    //原来是收起的，现在要展开，则需要将同层次展开的收起，然后再展开
    [self compareSameLevelWithModel:model row:row];
  }
  else {
    //点击的是最后一层数据，跳转到别的界面
    NSLog(@"最后一层");
  }
}

model.isOpen = !model.isOpen;

//滑动到屏幕顶部
for (int i = 0; i < _resultArray.count; i++) {
  OpenTest *openModel = _resultArray[i];

  if (openModel.isOpen && openModel.level == 0) {
    //将点击的cell滑动到屏幕顶部
    NSIndexPath *selectedPath = [NSIndexPath indexPathForRow:i inSection:0];
    [tableView scrollToRowAtIndexPath:selectedPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
  }
}

[tableView reloadData];
}