我們這里首先用一個(gè)簡(jiǎn)單的登錄頁面來說明一下MVVM構(gòu)架疲吸，之后再用一個(gè)網(wǎng)絡(luò)請(qǐng)求深入一下MVVM
- 1， 如果不使用MVVM構(gòu)架狮惜，把所有的東西都寫在控制器中高诺，比較臃腫，如下：
- (void)viewDidLoad {
[super viewDidLoad];
//1,登錄按鈕可否點(diǎn)擊的業(yè)務(wù)邏輯
RACSignal *combineSignal = [RACSignal combineLatest:@[_account.rac_textSignal, _pwd.rac_textSignal] reduce:^id(NSString *account, NSString *pwd){
return @(account.length && pwd.length);
}];
/*
[combineSignal subscribeNext:^(id x) {
_login.enabled = [x boolValue];
}];
*/
RAC(_login,enabled) = combineSignal;
//2,把點(diǎn)擊登錄按鈕邏輯抽離出來
RACCommand *loginCommand = [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {
NSLog(@"在這里請(qǐng)求數(shù)據(jù)---%@----%@",_account.text ,_pwd.text);
return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"把請(qǐng)求到的數(shù)據(jù)發(fā)送出去--在外面進(jìn)行調(diào)用"];
[subscriber sendCompleted];//這一步表示信息發(fā)送完成碾篡，之后調(diào)用會(huì)重新開始并發(fā)送信息虱而，如果沒有這一句，下一次就不會(huì)發(fā)送消息出去
return nil;
}];
}];
[loginCommand.executionSignals.switchToLatest subscribeNext:^(id x) {
NSLog(@"在外部拿到的數(shù)據(jù)-------%@", x);
}];
//3, 監(jiān)聽登錄按鈕點(diǎn)擊,執(zhí)行命令的業(yè)務(wù)邏輯即可
[[_login rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(id x) {
NSLog(@"點(diǎn)擊了登錄按鈕");
//點(diǎn)擊的時(shí)候進(jìn)行command的調(diào)用
[loginCommand execute:nil];
}];
}
- 2开泽，使用VMMV進(jìn)行構(gòu)架
- 控制器中代碼只需要如下：
-(LoginViewModel *)loginVM{
if(_loginVM == nil){
_loginVM = [[LoginViewModel alloc] init];
}
return _loginVM;
}
- (void)viewDidLoad {
[super viewDidLoad];
// mvvm
RAC(self.loginVM, account) = _account.rac_textSignal;
RAC(self.loginVM, pwd) = _pwd.rac_textSignal;
RAC(self.login, enabled) = _loginVM.loginEnableSignal;
[[_login rac_signalForControlEvents:UIControlEventTouchUpInside] subscribeNext:^(id x) {
NSLog(@"點(diǎn)擊了登錄按鈕");
[_loginVM.loginCommand execute:nil];
}];
[_loginVM.loginCommand.executionSignals.switchToLatest subscribeNext:^(id x) {
NSLog(@"%@",x);
}];
}
- 其余代碼都抽取到VM中了：
- (instancetype)init{
if (self = [super init]) {
//1,登錄按鈕屬性
//RACObserve是觀察者宏牡拇， 一旦被觀察內(nèi)容發(fā)生變化就發(fā)出信號(hào)
_loginEnableSignal = [RACSignal combineLatest:@[RACObserve(self, account), RACObserve(self, pwd)] reduce:^id(NSString *account, NSString *pwd){
return @(account.length && pwd.length);
}];
//2,登錄按鈕事件
_loginCommand = [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {
NSLog(@"在這里請(qǐng)求數(shù)據(jù)---%@----%@",self.account, self.pwd);
return [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
[subscriber sendNext:@"把請(qǐng)求到的數(shù)據(jù)發(fā)送出去--在外面進(jìn)行調(diào)用"];
[subscriber sendCompleted];//這一步表示信息發(fā)送完成，之后調(diào)用會(huì)重新開始并發(fā)送信息穆律，如果沒有這一句诅迷，下一次就不會(huì)發(fā)送消息出去
return nil;
}];
}];
}
return self;
}
3, 使用MVVM處理網(wǎng)絡(luò)登錄邏輯
首先控制器中只需要如下代碼：
//如果想要在外面拿到數(shù)據(jù)，需要先訂閱
[self.requestVM.requestCommand.executionSignals.switchToLatest subscribeNext:^(id x) {
NSLog(@"----%@",x);
}];
[self.requestVM.requestCommand execute:nil];
- 其他邏輯代碼都放在VM中众旗，需要注意的是，在存放邏輯代碼的時(shí)候趟畏，為了把請(qǐng)求到的數(shù)據(jù)傳遞出去贡歧，需要把請(qǐng)求代碼放在信號(hào)中，通過訂閱者發(fā)送出去赋秀，然后在命令中把信號(hào)返回就可以了利朵。
- (RACCommand *)requestCommand{
if (_requestCommand == nil) {
_requestCommand = [[RACCommand alloc] initWithSignalBlock:^RACSignal *(id input) {
NSLog(@"請(qǐng)求網(wǎng)絡(luò)數(shù)據(jù)");
RACSignal *signal = [RACSignal createSignal:^RACDisposable *(id<RACSubscriber> subscriber) {
AFHTTPSessionManager *manager = [AFHTTPSessionManager manager];
[manager GET:@"https://api.douban.com/v2/book/search" parameters:@{@"q":@"美女"} progress:^(NSProgress * _Nonnull downloadProgress) {
} success:^(NSURLSessionDataTask * _Nonnull task, id _Nullable responseObject) {
NSLog(@"zhangdanfeng");
[subscriber sendNext:responseObject];
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
}];
return nil;
}];
return signal;
}];
}
return _requestCommand;
}
