关键词：递归 多级菜单 复选

目标：

1.显示多级菜单，默认显示一级.

2.可以通过点击有子级的行展开菜单

3.通过复选框，改变选中状态。状态有全选、半选、未选中

4.可以扩展获取当前所选的条目集合

menu.gif

实现过程：

数据处理

1.首先根Datasource进行数据处理

2.生成一个handler:MultilevelDataHandler 将数据处理逻辑在handle处理，将数据处理隔离

MultilevelDataHandler *dataHandler = [MultilevelDataHandler sharedHandler];

[dataHandler setLevelKeys:@[@"second_category", @"knowledge"]]; //由于源数据中每层数据可能采用不同的key，所有我把每层的key依次添加到数组里面，以便数据转化

[dataHandler setReDataSource:dataSource]; // 将源数据交给handle处理

3.建立一个数据模型，需要用一些属性记录层级关系。最后我用了一个字典来记录原始的数据信息。

//

// MultilevelMenuModel.h

// MultilevelMenuWithCheckbox

Created by hyt on 2017/10/31.

// Copyright © 2017年 hyt. All rights reserved.

//#importtypedef NS_ENUM (NSInteger, MMSelectState){

selectNone,

selectHalf,

selectAll

};

@interface MultilevelMenuModel : NSObject

@property (nonatomic, assign) NSInteger MMLevel;

@property (nonatomic, assign) NSInteger MMIndex;

//@property (nonatomic, assign) NSInteger MMSuperIndex;

@property (nonatomic, strong) NSMutableArray *locationArray;

@property (nonatomic, strong) NSArray *MMSubArray;

@property (nonatomic, assign) MMSelectState MMSelectState;

@property (nonatomic, assign) BOOL MMIsOpen;

@property (nonatomic, strong) NSDictionary *dataDict; // original data

@end

这里是Demo的数据Json

json数据：

[{

"id": "",

"name": "",

"type": "",

"second_category": [{

"id": "",

"name": "",

"type": "",

"knowledge": [{

"id": "",

"name": "",

"type": ""

}]

}]

}]

4.将jsonDictionary转化成数据模型的时候，把层级关系也一并赋值。

由于数据层级数量的不确定性，这里用递归的方式把每层的数据结构都放到其父类的subArray当中。

- (MultilevelMenuModel *)getModelByDict:(NSDictionary *)dict

modelLevel:(NSInteger)level

modelIndex:(NSInteger)index

superIndex:(NSInteger)superIndex

locationArray:(NSMutableArray *)loactionArray{

MultilevelMenuModel *levelModel = [[MultilevelMenuModel alloc] init];

levelModel.MMLevel = level;

levelModel.MMIndex = index++;

// levelModel.MMSuperIndex = superIndex;

levelModel.dataDict = [NSDictionary dictionaryWithDictionary:dict];

levelModel.locationArray = [NSMutableArray arrayWithArray:loactionArray];

[levelModel.locationArray addObject:[NSNumber numberWithInteger:superIndex]];

if ([self checkModelHasSubArray:levelModel]) {

[self setModelSubArray:levelModel];

}

return levelModel;

}

- (void)setModelSubArray:(MultilevelMenuModel *)model {

NSString *key = [self getSubKeyByModel:model];

NSArray *subDictArray = model.dataDict[key];

model.MMSubArray = [self getModelArrayFromDictArray:subDictArray

modelLevel:model.MMLevel + 1

superIndex:model.MMIndex

locationArray:model.locationArray];

}

- (NSArray *)getModelArrayFromDictArray:(NSArray *)dictArray

modelLevel:(NSInteger)level

superIndex:(NSInteger)superIndex

locationArray:(NSMutableArray *)locationArray{

NSMutableArray *deArray = [NSMutableArray array];

NSInteger index = 0;

for (NSDictionary *dict in dictArray) {

MultilevelMenuModel *levelModel = [self getModelByDict:dict

modelLevel:level

modelIndex:index++

superIndex:superIndex

locationArray:locationArray];

[deArray addObject:levelModel];

}

return [NSArray arrayWithArray:deArray];

}

5.建一个新的数组用来存储要在tableView上展示的数据模型，按照父类子类，父类子类的顺序排列。我这里默认是把第一级全部关闭展示的

6.实现菜单展开关闭功能

根据点击的model的isOpen属性来判断是否展开。

展开时是把subArray中的子级添加到showData当中去，需注意判断子级当前的状态是否是已展开的，如果是的话需要递归调用展开方法。

关闭时是把subArray中的子级从showData中删除，也用递归的方法把子类的子类也一并删除。

删除子级的时候不影响子级的展开状态。

- (void)addSubModelToShowByModel:(MultilevelMenuModel *)superModel {

NSInteger superIndex = [self.showData indexOfObject:superModel]; //

for (MultilevelMenuModel *subModel in [[superModel.MMSubArray reverseObjectEnumerator] allObjects]) {

if (![self.showData containsObject:subModel]) {

[self.showData insertObject:subModel atIndex:superIndex + 1];

}

if (subModel.MMIsOpen == YES && subModel.MMSubArray.count > 0 ) {

[self addSubModelToShowByModel:subModel];

}

}

superModel.MMIsOpen = YES;

}

- (void)removeSubModelFromShowByModel:(MultilevelMenuModel *)superModel

closeIt:(BOOL)close{

if (superModel.MMSubArray.count == 0) {

return;

}

for (MultilevelMenuModel *subModel in superModel.MMSubArray) {

[self removeSubModelFromShowByModel:subModel closeIt:!subModel.MMIsOpen];

[self.showData removeObject:subModel];

}

superModel.MMIsOpen = !close;

}

7.实现复选框功能

用三个方法分别实现复修改选框的三种状态

每个方法中，都需要考虑当前model的状态改变对其父级与子级的影响

用model的subArray找到其子级，用locationArray记录的坐标找到其父类

父级和子级的状态改变也会影响到他们的父级和子级，所有用递归的方式修改状态

- (void)setModelToBeStateNone:(MultilevelMenuModel *)model {

// make current model unselected

model.MMSelectState = selectNone;

// make sublevel unselected

if (model.MMSubArray.count > 0) {

for (MultilevelMenuModel *subModel in model.MMSubArray) {

if (subModel.MMSelectState != selectNone) {

[self setModelToBeStateNone:subModel];

}

}

}

//make super model unselected

MultilevelMenuModel *supModel = [self findSuperModelBySubModel:model];

if (supModel == nil) {

return;

}

if ([self checkSubModeHasStateAll:supModel]) {

[self setModelToBeStateHalf:supModel];

} else if ([self checkSubModelHasSelected:supModel]) {

[self setModelToBeStateHalf:supModel];

} else {

supModel.MMSelectState = selectNone;

}

}

- (void)setModelToBeStateHalf:(MultilevelMenuModel *)model {

// make current model selected

model.MMSelectState = selectHalf;

//make super model half-selected

MultilevelMenuModel *supModel = [self findSuperModelBySubModel:model];

if (supModel == nil) {

return;

}

[self setModelToBeStateHalf:supModel];

}

- (void)setModelToBeStateAll:(MultilevelMenuModel *)model {

// make current model selected

model.MMSelectState = selectAll;

// make sublevel selected

if (model.MMSubArray.count > 0) {

for (MultilevelMenuModel *subModel in model.MMSubArray) {

if (subModel.MMSelectState != selectAll) {

[self setModelToBeStateAll:subModel];

}

}

}

//make super model selected

MultilevelMenuModel *supModel = [self findSuperModelBySubModel:model];

if (supModel == nil) {

return;

}

if ([self checkSubModelsBeStateAll:supModel]) {

[self setModelToBeStateAll:supModel];

} else {

[self setModelToBeStateHalf:supModel];

}

}

根据locationArray里记录的每一层父级的序号，找到当前model的父级

- (MultilevelMenuModel *)findSuperModelBySubModel:(MultilevelMenuModel *)subModel {

NSArray *location = subModel.locationArray;

if (location.count == 0) {

return nil;

}

MultilevelMenuModel *resultModel;

NSArray *dataSource = self.modelArray;

int i = 1;

while (i < location.count) {

int index = [location[i] intValue];

resultModel = dataSource[index];

dataSource = resultModel.MMSubArray;

i++;

}

return resultModel;

}

小结

由于层级数量的不确定性，所以多次使用到了递归的方式。要注意递归的结束条件，必须陷入死循环当中。

附上本文的Demo