效果圖如下：

要現實多級目錄，首先要做的是在記憶體構建樹型結構，通過這個樹型結構，當用戶點選了某個有子項的選單，其變會根據樹型結構將menu展開或收起。

下面是“樹”中節點的構造，在這裡並沒有使用CFTree，出於兩點考慮：一是menu的結構一般只需知道其子選單即可，是一個簡單應用；第二是專案內部有對C++不瞭解的童鞋。

#import <Foundation/Foundation.h>
@interface MyItem : NSObject
@property (nonatomic,retain)  NSString * title;
@property (nonatomic) NSInteger level;
@property (nonatomic, retain) NSMutableArray *subItems;
@property (nonatomic) BOOL isSubItemOpen;
@property (nonatomic) BOOL isSubCascadeOpen;
@end
 

選單級聯收起程式碼

#pragma mark -- insert
- (NSArray *)insertMenuIndexPaths:(MyItem *)item
{
    NSArray * arr;
    [treeItemsToInsert removeAllObjects];
    [self insertMenuObject:item];
    arr = [self insertIndexsOfMenuObject:treeItemsToInsert];
    return arr;
}
- (void) insertMenuObject:(MyItem *)item
{
    NSLog(@"%d",[_tableViewData indexOfObject:item]);
    if (item == nil)
    {
        return ;
    }
    
    NSIndexPath *path = [NSIndexPath indexPathForRow:[_tableViewData indexOfObject:item] inSection:0];
    
    MyItem *childItem;
    for (int i = 0; i<[item.subItems count] ; i++) {
        childItem = [item.subItems objectAtIndex:i];
        [_tableViewData insertObject:childItem atIndex:path.row + i +1];
        [treeItemsToInsert addObject:childItem];
        item.isSubItemOpen = YES;
    }
    
    for (int i = 0; i <[item.subItems count]; i ++) {
        childItem = [item.subItems objectAtIndex:i];
        
        if (childItem .isSubCascadeOpen) {
            [self insertMenuObject:childItem];
        }
        
    }
    return ;
    
}
- (NSArray *) insertIndexsOfMenuObject :(NSMutableArray *) array
{
    
    NSMutableArray * mutableArr;
    mutableArr = [NSMutableArray array];
    for (MyItem * item in array) {
        NSIndexPath *path = [NSIndexPath indexPathForRow:[_tableViewData indexOfObject:item] inSection:0];
        [mutableArr addObject:path];
    }
    return mutableArr;
}
 

在tableViewController裡邏輯要儘量簡單，其中在tableView:didSelectRowAtIndexPath裡程式碼如下

    MenuItemCell * cell;
    cell = (MenuItemCell *)[tableView cellForRowAtIndexPath:indexPath];
    if (cell.item.isSubItemOpen)
    {
        //remove
        NSArray * arr;
        arr = [_menuData deleteMenuIndexPaths:cell.item];
        if ([arr count] >0) {
            [tableView deleteRowsAtIndexPaths: arr withRowAnimation:UITableViewRowAnimationBottom];
        }
    }
    else
    {
        //insert
        NSArray * arr;
        arr = [_menuData insertMenuIndexPaths:cell.item];
        if ([arr count] >0) {
            [tableView insertRowsAtIndexPaths:arr withRowAnimation:UITableViewRowAnimationBottom];
        }
    }