前言

在iOS開發(fā)技術(shù)群里看到，一哥們求助樹狀圖怎么做，并附帶一張圖片。一看到這效果圖，第一反應(yīng)是這不是網(wǎng)頁形式UI嗎？產(chǎn)品是SB？當(dāng)層次過多，手機顯示不下怎么辦？好了，發(fā)牢騷到此結(jié)束。該實現(xiàn)的還是要去實現(xiàn)的，畢竟我們只是碼奴而不是狗產(chǎn)品。
先上一張實現(xiàn)的簡單效果圖：

Simulator Screen Shot 2018年1月22日 下午4.16.28.png

實現(xiàn)思路

1.在UITableView基礎(chǔ)上進(jìn)行封裝，組數(shù)為1，先展示根視圖；
2.難點：數(shù)據(jù)處理，怎么進(jìn)行展開和收縮。
3.展開處理：點擊cell，判斷有無子視圖，有：獲取子視圖數(shù)據(jù)，插入到點擊cell所在row的位置后面，更新數(shù)據(jù)源。插入方法insertRowsAtIndexPaths。無：則不作處理。
4.收縮：點擊cell，判斷該節(jié)點是否已經(jīng)展開，如果以展開，遍歷該節(jié)點下的所有子視圖，獲取所有已展開的數(shù)據(jù)，在原數(shù)據(jù)中刪除獲取的數(shù)據(jù)。并調(diào)用deleteRowsAtIndexPaths方法。

代碼實現(xiàn)

先看一下數(shù)據(jù)格式：

89F5D153-0E1B-4E50-A157-5A7D55FA64A3.png

模型代碼
.h文件

@interface Menu : NSObject

//標(biāo)題
@property (nonatomic, copy) NSString *type;

//子層次的數(shù)據(jù)
@property (nonatomic, copy) NSArray *subType;

//有無展開
@property (nonatomic, assign) BOOL isOpen;

//層次級別
@property (nonatomic, assign) NSInteger level;

+ (id)menuWithDict:(NSDictionary *)dict;

.m文件

@implementation Menu

+ (id)menuWithDict:(NSDictionary *)dict {
    return [[self alloc] initWithDict:dict];
}

- (id)initWithDict:(NSDictionary *)dict {
    if (self = [super init]) {
        [self setValuesForKeysWithDictionary:dict];
    }
    return self;
}

cell視圖

#import <UIKit/UIKit.h>
@class Menu;

@interface MenuCell : UITableViewCell
@property (weak, nonatomic) IBOutlet UIButton *selectBtn;

- (void)refreshUI:(Menu *)menu;

@end

#import "MenuCell.h"
#import "Menu.h"

@interface MenuCell ()

@property (weak, nonatomic) IBOutlet UILabel *type;
//距離左邊間距
@property (weak, nonatomic) IBOutlet NSLayoutConstraint *leftWidth;

@end

@implementation MenuCell

- (void)refreshUI:(Menu *)menu {
    self.type.text = menu.type;
    if (menu.subType.count == 0) {
    //無子視圖，隱藏左邊圖標(biāo)
        self.selectBtn.hidden = YES;
    } else {
        self.selectBtn.hidden = NO;
    }
  //每個層次距離左邊的間距
    self.leftWidth.constant = menu.level * 20 + 8;
}

VC

#import "MenuTableViewController.h"
#import "MenuCell.h"
#import "Menu.h"

@interface MenuTableViewController () <UITableViewDelegate,UITableViewDataSource>
@property (weak, nonatomic) IBOutlet UITableView *menuTableView;
//數(shù)據(jù)源
@property (nonatomic, strong) NSMutableArray *dataSource;
//展開或者收縮 存儲的indexpath
@property (nonatomic, strong) NSMutableArray *deleteOrInsertArray;

@end

@implementation MenuTableViewController

//懶加載數(shù)據(jù)源
- (NSMutableArray *)dataSource {
    if (!_dataSource) {
        _dataSource = [NSMutableArray new];
        NSArray *array = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Property List" ofType:@"plist"]];
        for (NSDictionary *dict in array) {
            Menu *menu = [Menu menuWithDict:dict];
            menu.level = 0;
            [_dataSource addObject:menu];
        }
    }
    return _dataSource;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    self.deleteOrInsertArray = [NSMutableArray array];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return self.dataSource.count;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    return 44;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    MenuCell *cell = [tableView dequeueReusableCellWithIdentifier:@"MenuCell"];
    [cell refreshUI:self.dataSource[indexPath.row]];
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    Menu *menu = self.dataSource[indexPath.row];
    if (menu.subType.count == 0) {
        return;
    } else {
        [self.deleteOrInsertArray removeAllObjects];
        if (menu.isOpen) {
            //收縮操作
            [self deleteRows:menu Row:indexPath.row];
            NSMutableIndexSet *set = [NSMutableIndexSet indexSet];
            for (int i = 0; i < self.deleteOrInsertArray.count; i ++) {
                NSIndexPath *path = self.deleteOrInsertArray[i];
                [set addIndex:path.row];
            }
            [self.dataSource removeObjectsAtIndexes:set];
            [self.menuTableView deleteRowsAtIndexPaths:self.deleteOrInsertArray withRowAnimation:UITableViewRowAnimationNone];
        } else {
            //展開操作
            for (int i = 0 ; i < menu.subType.count; i ++) {
                Menu *model = [Menu menuWithDict:menu.subType[i]];
                model.level = menu.level + 1;
                [self.dataSource insertObject:model atIndex:indexPath.row + i + 1];
                [self.deleteOrInsertArray addObject:[NSIndexPath indexPathForRow:indexPath.row + i + 1 inSection:0]];
                NSLog(@"%@---%ld",model.type,model.level);
            }
            [self.menuTableView insertRowsAtIndexPaths:self.deleteOrInsertArray withRowAnimation:UITableViewRowAnimationNone];
        }
    }
    menu.isOpen = !menu.isOpen;
    MenuCell *cell = (MenuCell *)[tableView cellForRowAtIndexPath:indexPath];
    cell.selectBtn.selected = menu.isOpen;
}

- (void)deleteRows:(Menu *)menu Row:(NSInteger)row {
    for (int i = 0; i < menu.subType.count; i ++) {
        Menu *model = self.dataSource[row + 1 + i];
        NSIndexPath *path = [NSIndexPath indexPathForRow:row + i + 1 inSection:0];
        [self.deleteOrInsertArray addObject:path];
        if (model.subType > 0 && model.isOpen) {
            model.isOpen = NO;
            [self deleteRows:menu Row:row + menu.subType.count - 1];
        }
    }
}

所有代碼都已貼出。