關鍵詞：遞歸 多級菜單 復選
目標：
1.顯示多級菜單，默認顯示一級.
2.可以通過點擊有子級的行展開菜單
3.通過復選框，改變選中狀態。狀態有全選、半選、未選中
4.可以擴展獲取當前所選的條目集合
menu.gif
實現過程：
數據處理
1.首先根Datasource進行數據處理
2.生成一個handler:MultilevelDataHandler 將數據處理邏輯在handle處理，將數據處理隔離
MultilevelDataHandler *dataHandler = [MultilevelDataHandler sharedHandler];
[dataHandler setLevelKeys:@[@"second_category", @"knowledge"]]; //由于源數據中每層數據可能采用不同的key，所有我把每層的key依次添加到數組里面，以便數據轉化
[dataHandler setReDataSource:dataSource]; // 將源數據交給handle處理
3.建立一個數據模型，需要用一些屬性記錄層級關系。最后我用了一個字典來記錄原始的數據信息。
//
// 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
這里是Demo的數據Json
json數據：
[{
"id": "",
"name": "",
"type": "",
"second_category": [{
"id": "",
"name": "",
"type": "",
"knowledge": [{
"id": "",
"name": "",
"type": ""
}]
}]
}]
4.將jsonDictionary轉化成數據模型的時候，把層級關系也一并賦值。
由于數據層級數量的不確定性，這里用遞歸的方式把每層的數據結構都放到其父類的subArray當中。
- (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.建一個新的數組用來存儲要在tableView上展示的數據模型，按照父類子類，父類子類的順序排列。我這里默認是把第一級全部關閉展示的
6.實現菜單展開關閉功能
根據點擊的model的isOpen屬性來判斷是否展開。
展開時是把subArray中的子級添加到showData當中去，需注意判斷子級當前的狀態是否是已展開的，如果是的話需要遞歸調用展開方法。
關閉時是把subArray中的子級從showData中刪除，也用遞歸的方法把子類的子類也一并刪除。
刪除子級的時候不影響子級的展開狀態。
- (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.實現復選框功能
用三個方法分別實現復修改選框的三種狀態
每個方法中，都需要考慮當前model的狀態改變對其父級與子級的影響
用model的subArray找到其子級，用locationArray記錄的坐標找到其父類
父級和子級的狀態改變也會影響到他們的父級和子級，所有用遞歸的方式修改狀態
- (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];
}
}
根據locationArray里記錄的每一層父級的序號，找到當前model的父級
- (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;
}
小結
由于層級數量的不確定性，所以多次使用到了遞歸的方式。要注意遞歸的結束條件，必須陷入死循環當中。
