Android Studio 登录活动模板认证

Question

正如标题所述，我使用的是最新版本的 android studio 登录活动模板，但是我不确定如何正确验证用户，因为目前，只要凭据通过长度验证，任何人都可以登录in. 我计划将来调用数据库，但现在我想知道如何添加占位符凭据

这是登录数据源文件，我假设需要在其中进行身份验证，但是我不确定如何添加它。

package com.example.tkgapp.data;

import com.example.tkgapp.data.model.LoggedInUser;

import java.io.IOException;

/**
 * Class that handles authentication w/ login credentials and retrieves user information.
 */
public class LoginDataSource {

    public Result<LoggedInUser> login(String username, String password) {

        try {
            // TODO: handle loggedInUser authentication

            LoggedInUser fakeUser =
                    new LoggedInUser(
                            java.util.UUID.randomUUID().toString(),
                            "Jane Doe");
            return new Result.Success<>(fakeUser);
        } catch (Exception e) {
            return new Result.Error(new IOException("Error logging in", e));
        }
    }

    public void logout() {
        // TODO: revoke authentication
    }
}

这是主要的 loginviewmodel 文件，它处理所涉及的大多数其他验证

package com.example.tkgapp.ui.login;

import android.util.Patterns;

import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;

import com.example.tkgapp.R;
import com.example.tkgapp.data.LoginRepository;
import com.example.tkgapp.data.Result;
import com.example.tkgapp.data.model.LoggedInUser;

public class LoginViewModel extends ViewModel {

    private MutableLiveData<LoginFormState> loginFormState = new MutableLiveData<>();
    private MutableLiveData<LoginResult> loginResult = new MutableLiveData<>();
    private LoginRepository loginRepository;

    LoginViewModel(LoginRepository loginRepository) {
        this.loginRepository = loginRepository;
    }

    LiveData<LoginFormState> getLoginFormState() {
        return loginFormState;
    }

    LiveData<LoginResult> getLoginResult() {
        return loginResult;
    }

    public void login(String username, String password) {
        // can be launched in a separate asynchronous job
        Result<LoggedInUser> result = loginRepository.login(username, password);

        if (result instanceof Result.Success) {
            LoggedInUser data = ((Result.Success<LoggedInUser>) result).getData();
            loginResult.setValue(new LoginResult(new LoggedInUserView(data.getDisplayName())));
        } else {
            loginResult.setValue(new LoginResult(R.string.login_failed));
        }
    }

    public void loginDataChanged(String username, String password) {
        if (!isUserNameValid(username)) {
            loginFormState.setValue(new LoginFormState(R.string.invalid_username, null));
        } else if (!isPasswordValid(password)) {
            loginFormState.setValue(new LoginFormState(null, R.string.invalid_password));
        } else {
            loginFormState.setValue(new LoginFormState(true));
        }
    }

    // A placeholder username validation check
    private boolean isUserNameValid(String username) {
        if (username == null) {
            return false;
        }
        if (username.contains("@")) {
            return Patterns.EMAIL_ADDRESS.matcher(username).matches();
        } else {
            return username.trim().isEmpty();

        }
    }

    // A placeholder password validation check
    private boolean isPasswordValid(String password) {
        return password != null && password.trim().length() > 5 ;
    }
}