在MVVM 中，view 和 view controller正式联系在一起，我们把它们视为一个组件
view 和 view controller 都不能直接引用model，而是引用视图模型（viewModel）
viewModel 是一个放置用户输入验证逻辑，视图显示逻辑，发起网络请求和其他代码的地方
view 引用viewModel ，但反过来不行（即不要在viewModel中引入#import UIKit.h，任何视图本身的引用都不应该放在viewModel中）（PS：基本要求，必须满足）
viewModel 引用model，但反过来不行
本文里用MVVM模式，以及RAC双向数据绑定，来讲解“未读消息”的标记这个小栗子（小红点的隐藏与显示）。效果图
思路讲解：
viewModel 绑定整个视图，通过viewModel获得列表model后，创建cellModel（cell的viewModel），每个cell绑定cellModel，cell根据cellModel变化而变化
结构：
image.png
上代码
viewController：viewWillAppear都去获取第一条消息的ID
@interface TJMMineViewController ()
@property (weak, nonatomic) IBOutlet UITableView *tableView;
@property (nonatomic, strong) TJMMineHeader *mineHeader;
@property (strong, nonatomic) IBOutlet TJMMineViewModel *viewModel;
@end
@implementation TJMMineViewController
#pragma mark - view life cycle
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
[self configViews];
[self configTableview];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[_viewModel getSignalMessage];//viewWillAppear都去获取第一条消息的ID
}
#pragma mark - configViews
- (void)configViews {
[self setTitle:@"我 的" fontSize:18 colorHexValue:0x73d7ff];
[self setRightNaviItemWithImageName:@"mine_setting" orTitle:nil titleColorHexValue:0 fontSize:0];
}
- (void)configTableview {
self.tableView.tableHeaderView = self.mineHeader;
[_tableView registerNib:[UINib nibWithNibName:@"TJMMineCell" bundle:nil] forCellReuseIdentifier:cMineCell];
}
#pragma mark - UITableViewDelegate, UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return self.viewModel.dataSource.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
TJMMineCell *cell = [tableView dequeueReusableCellWithIdentifier:cMineCell forIndexPath:indexPath];
cell.cellModel = self.viewModel.dataSource[indexPath.row];//绑定cellModel
return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return self.viewModel.rowHeight;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[TJMUnloginView showWithLoginResult:^{
TJMMineCellModel *cellModel = self.viewModel.dataSource[indexPath.row];
[self performSegueWithIdentifier:cellModel.segueId sender:nil];
}];
}
model.h
@interface TJMMineModel : NSObject
@property (nonatomic, copy) NSString *imageName;
@property (nonatomic, copy) NSString *title;
@property (nonatomic, copy) NSString *segueId;
@property (nonatomic, assign) BOOL isMessageItem;//如果不是消息那一行则为NO
@end
viewModel.h
@interface TJMMineViewModel : TJMListBaseViewModel
@property (nonatomic, assign) CGFloat rowHeight;
/**获取消息列表的第一条数据，并对比*/
- (void)getSignalMessage;
@end
viewModel.m
1.得到model array 后，用RAC map 方法 将 [model] 转换为包含model的[cellModel]
NSArray *mapArr = [[array.rac_sequence map:^id _Nullable(id _Nullable value) {
TJMMineCellModel *cellModel = [[TJMMineCellModel alloc]init];
cellModel.model = value;
return cellModel;
}] array];
2.获取消息列表的第一条数据，与本地数据对比，如果不一样则表示有新消息，想cellModel的 isExitUnreadMsg 属性 标记为YES，反之标记为NO。（此时cell 已绑定了 cellModel 所以 isExitUnreadMsg 变化 cell 也会跟着变化）
NSString *unreadId = [[NSUserDefaults standardUserDefaults] stringForKey:kUnreadMessageId];
TJMMessageModel *model = [TJMMessageModel mj_objectWithKeyValues:successObj[@"data"]];
TJMMessageRecordModel *record = model.records.firstObject;
if (!unreadId) {
[[NSUserDefaults standardUserDefaults] setObject:record.ID forKey:kUnreadMessageId];
} else {
TJMMineCellModel *msgCellModel = self.dataSource[2];
if (![unreadId isEqualToString:record.ID]) {
msgCellModel.isExitUnreadMsg = YES;
} else {
msgCellModel.isExitUnreadMsg = NO;
}
}
完整代码
- (id)init {
if (self = [super init]) {
//获取Model
NSArray *array = [TJMMineModel mj_objectArrayWithFile:[[NSBundle mainBundle] pathForResource:@"TJMMineModel" ofType:@"plist"]];
NSArray *mapArr = [[array.rac_sequence map:^id _Nullable(id _Nullable value) {
TJMMineCellModel *cellModel = [[TJMMineCellModel alloc]init];
cellModel.model = value;
return cellModel;
}] array];
self.dataSource = [NSMutableArray arrayWithArray:mapArr];
}
return self;
}
#pragma mark - lazy loading
- (CGFloat)rowHeight {
if (!_rowHeight) {
self.rowHeight = 70.f * TJMHeightRatio;
}
return _rowHeight;
}
- (void)getSignalMessage {
TJMTokenModel *tokenModel = [TJMSandBoxManager getTokenModel];
if (tokenModel) {
NSString *unreadId = [[NSUserDefaults standardUserDefaults] stringForKey:kUnreadMessageId];
NSDictionary *parameters = @{@"currentPage" : @1,
@"pageSize" : @1,
@"customerId" : tokenModel.userId
};
[TJMNetworkingManager GET:TJMApiBasicAddress(TJMGetMessage) isNeedToken:YES parameters:parameters progress:nil success:^(id successObj, NSString *msg) {
TJMMessageModel *model = [TJMMessageModel mj_objectWithKeyValues:successObj[@"data"]];
TJMMessageRecordModel *record = model.records.firstObject;
if (!unreadId) {
[[NSUserDefaults standardUserDefaults] setObject:record.ID forKey:kUnreadMessageId];
} else {
TJMMineCellModel *msgCellModel = self.dataSource[2];
if (![unreadId isEqualToString:record.ID]) {
msgCellModel.isExitUnreadMsg = YES;
} else {
msgCellModel.isExitUnreadMsg = NO;
}
}
} failure:^(NSInteger code, NSString *failString) {
}];
}
}
cell.h
@interface TJMMineCell : UITableViewCell
@property (weak, nonatomic) IBOutlet UIImageView *iconImageView;
@property (weak, nonatomic) IBOutlet TJMLabel *titleLabel;
@property (weak, nonatomic) IBOutlet UIView *dotView;
@property (nonatomic, strong) TJMMineCellModel *cellModel;
@end
cell.m
这里只说明消息那个小红点的绑定，
先看combineLatestWith:reduce: 方法，绑定两个信号，判断状态返回一个新的信号；
所以dotView 的隐藏与否，取决于这个signal 是否满足，“reduce”后的判断条件（即这个cell既要是“我的消息”---->isMessageItem == YES，且还要有未读消息isExitUnreadMsg == YES，才会显示小红点）
if (isMessageItem.boolValue) {
if (isExitUnreadMsg.boolValue) {
return @0;
} else {
return @1;
}
} else {
return @1;
}
完整代码
- (void)setCellModel:(TJMMineCellModel *)cellModel {
if ([cellModel isEqual:_cellModel]) return;
_cellModel = cellModel;
RAC(_iconImageView, image) = RACObserve(cellModel, image);
RAC(_titleLabel, text) = RACObserve(cellModel, title);
RAC(_dotView, hidden) = [RACSignal combineLatest:@[RACObserve(cellModel, isMessageItem), RACObserve(cellModel, isExitUnreadMsg)] reduce:^id (NSNumber *isMessageItem, NSNumber *isExitUnreadMsg){
if (isMessageItem.boolValue) {
if (isExitUnreadMsg.boolValue) {
return @0;
} else {
return @1;
}
} else {
return @1;
}
}];
}
cellModel.h
@interface TJMMineCellModel : TJMBaseViewModel
@property (nonatomic, strong) TJMMineModel *model;
@property (nonatomic, copy) NSString *imageName;
@property (nonatomic, copy) NSString *title;
@property (nonatomic, copy) NSString *segueId;
@property (nonatomic, assign) BOOL isMessageItem;
@property (nonatomic, assign) BOOL isExitUnreadMsg;
@property (nonatomic, strong) UIImage *image;
@end
cellModel.m 就是绑定model
- (void)setModel:(TJMMineModel *)model {
if ([model isEqual:_model]) return;
_model = model;
RAC(self, title) = RACObserve(_model, title);
RAC(self, isMessageItem) = RACObserve(_model, isMessageItem);
@weakify(self);
[RACObserve(_model, imageName) subscribeNext:^(NSString * _Nullable x) {
@strongify(self);
self.image = [UIImage imageNamed:x];
}];
RAC(self, segueId) = RACObserve(_model, segueId);
}