运行应用程序后的android studio错误

Question

当我运行应用程序并登录时，用户数据没有出现在仪表板中，修改代码后出现此错误

错误：SessionHandler 类中的方法 loginUser 不能应用于给定类型； 必需：字符串，字符串，字符串 找到：字符串，字符串 原因：实际参数列表和形式参数列表的长度不同

我该如何解决这个错误？

登录行为类

package com.androidigniter.loginandregistration;

import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;

import org.json.JSONException;
import org.json.JSONObject;

public class LoginActivity extends AppCompatActivity {
    private static final String KEY_STATUS = "status";
    private static final String KEY_MESSAGE = "message";
    private static final String KEY_FULL_NAME = "full_name";
    private static final String KEY_USERNAME = "username";
    private static final String KEY_PASSWORD = "password";
    private static final String KEY_EMPTY = "";
    private EditText etUsername;
    private EditText etPassword;
    private String username;
    private String password;
    private ProgressDialog pDialog;
    private String login_url = "http://192.168.1.102/member/login.php";
    private SessionHandler session;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        session = new SessionHandler(getApplicationContext());

        if(session.isLoggedIn()){
            loadDashboard();
        }
        setContentView(R.layout.activity_login);

        etUsername = findViewById(R.id.etLoginUsername);
        etPassword = findViewById(R.id.etLoginPassword);

        Button register = findViewById(R.id.btnLoginRegister);
        Button login = findViewById(R.id.btnLogin);

        //Launch Registration screen when Register Button is clicked
        register.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(LoginActivity.this, RegisterActivity.class);
                startActivity(i);
                finish();
            }
        });

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Retrieve the data entered in the edit texts
                username = etUsername.getText().toString().toLowerCase().trim();
                password = etPassword.getText().toString().trim();
                if (validateInputs()) {
                    login();
                }
            }
        });
    }

    /**
     * Launch Dashboard Activity on Successful Login
     */
    private void loadDashboard() {
        Intent i = new Intent(getApplicationContext(), DashboardActivity.class);
        startActivity(i);
        finish();

    }

    /**
     * Display Progress bar while Logging in
     */

    private void displayLoader() {
        pDialog = new ProgressDialog(LoginActivity.this);
        pDialog.setMessage("Logging In.. Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();

    }

    private void login() {
        displayLoader();
        JSONObject request = new JSONObject();
        try {
            //Populate the request parameters
            request.put(KEY_USERNAME, username);
            request.put(KEY_PASSWORD, password);

        } catch (JSONException e) {
            e.printStackTrace();
        }
        JsonObjectRequest jsArrayRequest = new JsonObjectRequest
                (Request.Method.POST, login_url, request, new Response.Listener<JSONObject>() {
                    @Override
                    public void onResponse(JSONObject response) {
                        pDialog.dismiss();
                        try {
                            //Check if user got logged in successfully

                            if (response.getInt(KEY_STATUS) == 0) {
                                session.loginUser(username,response.getString(KEY_FULL_NAME));
                                loadDashboard();

                            }else{
                                Toast.makeText(getApplicationContext(),
                                        response.getString(KEY_MESSAGE), Toast.LENGTH_SHORT).show();

                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                }, new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        pDialog.dismiss();

                        //Display error message whenever an error occurs
                        Toast.makeText(getApplicationContext(),
                                error.getMessage(), Toast.LENGTH_SHORT).show();

                    }
                });

        // Access the RequestQueue through your singleton class.
        MySingleton.getInstance(this).addToRequestQueue(jsArrayRequest);
    }

    /**
     * Validates inputs and shows error if any
     * @return
     */
    private boolean validateInputs() {
        if(KEY_EMPTY.equals(username)){
            etUsername.setError("Username cannot be empty");
            etUsername.requestFocus();
            return false;
        }
        if(KEY_EMPTY.equals(password)){
            etPassword.setError("Password cannot be empty");
            etPassword.requestFocus();
            return false;
        }
        return true;
    }
}

会话处理类

package com.androidigniter.loginandregistration;

import android.content.Context;
import android.content.SharedPreferences;

import java.util.Date;

/**
 * Created by AndroidIgniter on 23 Mar 2019 020.
 */

public class SessionHandler {
    private static final String PREF_NAME = "UserSession";
    private static final String KEY_USERNAME = "username";
    private static final String KEY_EXPIRES = "expires";
    private static final String KEY_FULL_NAME = "full_name";
    private static final String KEY_CARD_ID = "cardid";
    private static final String KEY_EMPTY = "";
    private Context mContext;
    private SharedPreferences.Editor mEditor;
    private SharedPreferences mPreferences;

    public SessionHandler(Context mContext) {
        this.mContext = mContext;
        mPreferences = mContext.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
        this.mEditor = mPreferences.edit();
    }

    /**
     * Logs in the user by saving user details and setting session
     *
     * @param username
     * @param fullName
     * @param cardid
     */
    public void loginUser(String username, String fullName , String cardid) {
        mEditor.putString(KEY_USERNAME, username);
        mEditor.putString(KEY_FULL_NAME, fullName);
        mEditor.putString(KEY_CARD_ID, cardid);
        Date date = new Date();

        //Set user session for next 7 days
        long millis = date.getTime() + (7 * 24 * 60 * 60 * 1000);
        mEditor.putLong(KEY_EXPIRES, millis);
        mEditor.commit();
    }

    /**
     * Checks whether user is logged in
     *
     * @return
     */
    public boolean isLoggedIn() {
        Date currentDate = new Date();

        long millis = mPreferences.getLong(KEY_EXPIRES, 0);

        /* If shared preferences does not have a value
         then user is not logged in
         */
        if (millis == 0) {
            return false;
        }
        Date expiryDate = new Date(millis);

        /* Check if session is expired by comparing
        current date and Session expiry date
        */
        return currentDate.before(expiryDate);
    }

    /**
     * Fetches and returns user details
     *
     * @return user details
     */
    public User getUserDetails() {
        //Check if user is logged in first
        if (!isLoggedIn()) {
            return null;
        }
        User user = new User();
        user.setUsername(mPreferences.getString(KEY_USERNAME, KEY_EMPTY));
        user.setFullName(mPreferences.getString(KEY_FULL_NAME, KEY_EMPTY));
        user.setCardId(mPreferences.getString(KEY_CARD_ID, KEY_EMPTY));
        user.setSessionExpiryDate(new Date(mPreferences.getLong(KEY_EXPIRES, 0)));

        return user;
    }

    /**
     * Logs out user by clearing the session
     */
    public void logoutUser(){
        mEditor.clear();
        mEditor.commit();
    }

}

用户类

package com.androidigniter.loginandregistration;

import java.util.Date;

/**
 * Created by AndroidIgniter on 23 Mar 2019 020.
 */

public class User {
    String username;
    String fullName;
    String cardid;

    Date sessionExpiryDate;

    public void setUsername(String username) {
        this.username = username;
    }

    public void setFullName(String fullName) {
        this.fullName = fullName;
    }

    public void setCardId(String cardid) {
        this.cardid = cardid;
    }

    public void setSessionExpiryDate(Date sessionExpiryDate) {
        this.sessionExpiryDate = sessionExpiryDate;
    }

    public String getUsername() {
        return username;
    }

    public String getFullName() {
        return fullName;
    }
    public String getCardId() {
        return cardid;
    }
    public Date getSessionExpiryDate() {
        return sessionExpiryDate;
    }
}

Answer 1

你对loginUser的定义是：

public void loginUser(String username, String fullName , String cardid) 

然而，当您致电 loginUser 时：

session.loginUser(username,response.getString(KEY_FULL_NAME));

您使用 2 个String 参数调用它。您需要提供另一个参数 cardid 或将函数定义更改为只需要 2 个参数，如下所示：

public void loginUser(String username, String fullName)