Question

我正在尝试创建一个共享的用户数据提供程序：

import {Injectable} from '@angular/core';


@Injectable()

export class User {

  public name: string;
  public email: string;
  public password: string;
  public birthday: string;
  public settings: Settings;
  public loggedIn: boolean;

  constructor({
                name = null, email = null, password = null, birthday = null,
                settings = new Settings(),loggedIn = false
              }: {
    name?: string; email?: string; password?: string; birthday?: string;
     settings?: Settings; loggedIn?: boolean;
  } = {}) {

    this.name = name;
    this.email = email;
    this.password = password;
    this.birthday = birthday;
    this.settings = settings;
    this.loggedIn = loggedIn;
  }

  /**
   * @returns {number} the user's age.
   */
  get age(): number {
    let age = Math.abs(Date.now() - new Date(this.birthday).getTime());
    return Math.floor(age * 3.16887646E-11);
  }

}

@Injectable()
export class Settings {
  notificationSettings: NotificationSettings;
  preferencesSettings: PreferencesSettings;

  constructor({
                notificationSettings = new NotificationSettings(),
                preferencesSettings = new PreferencesSettings()
              }: {
    notificationSettings?: NotificationSettings;
    preferencesSettings?: PreferencesSettings;
  } = {}) {

    this.notificationSettings = notificationSettings;
    this.preferencesSettings = preferencesSettings;
  }
}

@Injectable()
export class NotificationSettings {
  // TODO
}

@Injectable()
export class PreferencesSettings {
  // TODO
}

在应用程序组件中，我声明了提供程序，以便使用户全局可用。

当我尝试构建项目时，出现Can't resolve all parameters for User: (?)错误。

问题出现是因为User构造函数中的设置，但我很难在逻辑中找到错误。

Answer 1

我不确定确切的情况，但您的代码问题是您需要知道一件事是共享服务，另一件事是将在该服务中使用的模型（也可能在某些其他服务中使用）。

模型不应该是可注射的，它们只是类。只有服务应该。因此，在您的情况下，我们可以从创建应用的模型开始，然后我们可以添加AccountService来保存用户的实例。

我已经更改了用作模型的类的名称，以避免混淆（我认为如果名称以-Model结尾，则更容易知道某些东西是模型）

import { Injectable } from '@angular/core';

export class NotificationSettingsModel {
  // TODO
}

export class PreferencesSettingsModel {
  // TODO
}

export class SettingsModel {
  public notificationSettings: NotificationSettingsModel;
  public preferencesSettings: PreferencesSettingsModel;

  constructor() {
    this.notificationSettings = new NotificationSettingsModel();
    this.preferencesSettings = new PreferencesSettingsModel();
  }
}

export class UserModel {
    public name: string;
    public email: string;
    public password: string;
    public birthday: string;
    public settings: SettingsModel;

    constructor() {
        this.name = null;
        this.email = null;
        this.password = null;
        this.birthday = null;
        this.settings = new SettingsModel();
    }

    /**
    * @returns {number} the user's age.
    */
    get age(): number {
        let age = Math.abs(Date.now() - new Date(this.birthday).getTime());
        return Math.floor(age * 3.16887646E-11);
    }
}


@Injectable()
export class AccountService {

    public currentUser: UserModel = null;
    constructor() {}

    public isLoggedIn(): boolean {
        return this.currentUser !== null;
    }

}

在此之后，您需要在主应用模块（或共享模块）中添加AccountService。例如，您可以将其添加到app.module.ts文件中：

@NgModule({
  declarations: [...],
  imports: [...],
  bootstrap: [IonicApp],
  entryComponents: [...],
  providers: [AccountService] // <- Here!
})
export class AppModule { }

然后在你的页面中，只需注入并使用它：

// imports...

@Component({...})
export class HomePage{

    constructor(public accountService: AccountService) {}

    public someMethod(): void {
      // You can access the properties
      // this.accountService.currentUser;

      // And also the methods: 
      // this.accountService.isLoggedIn();
    }

}

无法解析用户的所有参数

1 个答案: