先看效果

ZZFoldCell.gif

源碼

https://github.com/guoxuzan/ZZFoldCell

原理分析

圖中的行政區(qū)域是樹形結(jié)構(gòu)蔓肯，但UITableView的Cell是隊列形式小压，展開與折疊效果靠UITableView的Cell插入刪除實現(xiàn)战授。

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    [tableView beginUpdates];
    if (//要展開) {
        //子節(jié)點成為兄弟節(jié)點
        
        //insertRows
        [tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];
    }else {//要折疊
        //兄弟節(jié)點變回子節(jié)點
        
        //deleteRows
        [tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];
    }
    [tableView endUpdates];
}

樹的操作靠Model配合data實現(xiàn)

@interface ZZFoldCellModel : NSObject

@property(nonatomic,copy) NSString *text;//cell展示內(nèi)容
@property(nonatomic,copy) NSString *level;//節(jié)點級別
//...

@property(nonatomic,assign) NSUInteger belowCount;//子節(jié)點已經(jīng)轉(zhuǎn)為兄弟節(jié)點的個數(shù)
@property(nullable,nonatomic) ZZFoldCellModel *supermodel;//父節(jié)點
@property(nonatomic,strong) NSMutableArray<__kindof ZZFoldCellModel *> *submodels;//子節(jié)點

+ (instancetype)modelWithDic:(NSDictionary *)dic;//初始化
- (NSArray *)open;//返回并刪除子節(jié)點
- (void)closeWithSubmodels:(NSArray *)submodels;//插入子節(jié)點

@end

具體實現(xiàn)

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    ZZFoldCellModel *didSelectFoldCellModel = self.data[indexPath.row];
    
    [tableView beginUpdates];
    if (didSelectFoldCellModel.belowCount == 0) {
        
        //Data
        NSArray *submodels = [didSelectFoldCellModel open];
        NSIndexSet *indexes = [NSIndexSet indexSetWithIndexesInRange:((NSRange){indexPath.row + 1,submodels.count})];
        [self.data insertObjects:submodels atIndexes:indexes];
        
        //Rows
        NSMutableArray *indexPaths = [NSMutableArray new];
        for (int i = 0; i < submodels.count; i++) {
            NSIndexPath *insertIndexPath = [NSIndexPath indexPathForRow:(indexPath.row + 1 + i) inSection:indexPath.section];
            [indexPaths addObject:insertIndexPath];
        }
        [tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];
        
    }else {
        
        //Data
        NSArray *submodels = [self.data subarrayWithRange:((NSRange){indexPath.row + 1,didSelectFoldCellModel.belowCount})];
        [didSelectFoldCellModel closeWithSubmodels:submodels];
        [self.data removeObjectsInArray:submodels];
        
        //Rows
        NSMutableArray *indexPaths = [NSMutableArray new];
        for (int i = 0; i < submodels.count; i++) {
            NSIndexPath *insertIndexPath = [NSIndexPath indexPathForRow:(indexPath.row + 1 + i) inSection:indexPath.section];
            [indexPaths addObject:insertIndexPath];
        }
        [tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];
    }
    [tableView endUpdates];
}