我正在尝试使用Volley，PHP，MySQL进行登录会话，但我的登录布局无法加载。我不知道发生了什么，在我的logcat中它说“ java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.merylle.themoneyger / com.example.merylle.themoneyger.activity.LoginActivity}：java.lang .ClassCastException：com.example.merylle.themoneyger.activity.LoginActivity无法转换为com.example.merylle.themoneyger.activity.MainActivity“
这是由于“原因：java.lang.ClassCastException：com.example.merylle.themoneyger.activity.LoginActivity无法转换为com.example.merylle.themoneyger.activity.MainActivity”
有人可以帮助我识别我的错误吗？这是我的代码
SessionManager.java
public class SessionManager {
SharedPreferences sharedPreferences;
public SharedPreferences.Editor editor;
public Context context;
int PRIVATE_MODE=0;
private static final String PREF_NAME = "MONEYGER";
private static final String LOGIN = "IS_LOGIN";
public static final String FIRSTNAME = "NAME";
public static final String EMAIL = "EMAIL";
public static final String USERID = "USERID";
public SessionManager(Context context) {
this.context = context;
sharedPreferences = context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
editor = sharedPreferences.edit();
}
public void createSession(String firstname, String email) {
editor.putBoolean(LOGIN, true);
editor.putString(FIRSTNAME, firstname);
editor.putString(EMAIL, email);
/*editor.putString(USERID, userid);*/
editor.apply();
}
public boolean isLoggin(){
return sharedPreferences.getBoolean(LOGIN, false);
}
public void checkLogin() {
if (!this.isLoggin()) {
Intent i = new Intent(context, LoginActivity.class);
context.startActivity(i);
((MainActivity)context).finish();
}
}
public HashMap<String, String> getUserDetail() {
HashMap<String, String> user = new HashMap<>();
user.put(FIRSTNAME, sharedPreferences.getString(FIRSTNAME, null));
user.put(EMAIL, sharedPreferences.getString(EMAIL, null));
/*user.put(USERID, sharedPreferences.getString(USERID, null));*/
return user;
}
public void logout() {
editor.clear();
editor.commit();
Intent i = new Intent(context, LoginActivity.class);
context.startActivity(i);
((MainActivity)context).finish();
}
}
LoginActivity.java
public class LoginActivity extends Activity {
TextView title;
Typeface marcellus;
private EditText emailuser, passworduser;
TextView forgot;
private Button login, register;
private ProgressBar progressBar;
private static String HttpURL = "http://10.0.2.2:63343/TheMoneyger/api/user-login.php?";
SessionManager sessionManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
sessionManager = new SessionManager(this);
sessionManager.checkLogin();
title = (TextView) findViewById(R.id.txtTitle);
marcellus = Typeface.createFromAsset(getAssets(), "marcellus.ttf");
title.setTypeface(marcellus);
emailuser = (EditText) findViewById(R.id.txtEmail);
passworduser = (EditText) findViewById(R.id.txtPassword);
login = (Button) findViewById(R.id.btnLogin);
forgot = (TextView) findViewById(R.id.txtForgotPW);
register = (Button) findViewById(R.id.btnRegister);
progressBar = (ProgressBar)findViewById(R.id.progressBar3);
login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String mEmail = emailuser.getText().toString().trim();
String mPass = passworduser.getText().toString().trim();
if(!mEmail.isEmpty() || !mPass.isEmpty()) {
Login(mEmail, mPass);
}
else {
emailuser.setError("Please insert email");
passworduser.setError("Please insert password");
}
}
});
register.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent registration = new Intent(LoginActivity.this, RegistrationActivity.class);
startActivity(registration);
}
});
forgot.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent forgot = new Intent(LoginActivity.this, ForgotPassword.class);
startActivity(forgot);
}
});
}
private void Login(final String emailuser, final String passworduser) {
progressBar.setVisibility(View.VISIBLE);
login.setVisibility(View.GONE);
StringRequest stringRequest = new StringRequest(Request.Method.POST, HttpURL,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
try {
JSONObject jsonObject = new JSONObject(response);
String success = jsonObject.getString("success");
JSONArray jsonArray = jsonObject.getJSONArray("login");
if (success.equals("1")) {
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject object = jsonArray.getJSONObject(i);
String firstname = object.getString("firstname").trim();
String email = object.getString("email").trim();
String id = object.getString("userid").trim();
sessionManager.createSession(firstname, email);
Intent intent = new Intent(LoginActivity.this, MainActivity.class);
intent.putExtra("firstname", firstname);
intent.putExtra("email", email);
startActivity(intent);
finish();
}
}
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(LoginActivity.this, "Something went wrong.. " + e.toString(), Toast.LENGTH_SHORT).show();
login.setVisibility(View.VISIBLE);
progressBar.setVisibility(View.GONE);
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(LoginActivity.this, "Something went wrong.. " + error.toString(), Toast.LENGTH_SHORT).show();
login.setVisibility(View.VISIBLE);
progressBar.setVisibility(View.GONE);
}
}) {
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String, String> params = new HashMap<>();
params.put("email", emailuser);
params.put("password", passworduser);
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(stringRequest);
}
}
Home2.java
public class Home2 extends Fragment {
private TextView profileName, profileEmail;
CardView cv1, cv2, cv3, cv4, cv5, cv6;
SessionManager sessionManager;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_home, container, false);
sessionManager = new SessionManager(getActivity().getApplicationContext());
sessionManager.checkLogin();
cv1 = (CardView)view.findViewById(R.id.cv1); //settings
cv2 = (CardView)view.findViewById(R.id.cv2); //profile
cv3 = (CardView)view.findViewById(R.id.cv3); //expenses summary
cv4 = (CardView)view.findViewById(R.id.cv4); //budget summary
cv5 = (CardView)view.findViewById(R.id.cv5); //report
cv6 = (CardView)view.findViewById(R.id.cv6); //logout
profileName = (TextView)view.findViewById(R.id.txtProfileName); //display profilename
profileEmail = (TextView)view.findViewById(R.id.txtProfileEmail); //display profileemail
HashMap<String, String> user = sessionManager.getUserDetail();
String mName = user.get(sessionManager.FIRSTNAME);
String mEmail = user.get(sessionManager.EMAIL);
profileName.setText(mName);
profileEmail.setText(mEmail);
return view;
}
}
user-login.php
<?php
if ($_SERVER['REQUEST_METHOD']=='POST') {
$email = $_POST['email'];
$password = $_POST['password'];
require_once 'config.php';
$sql = "SELECT * FROM users WHERE email='$username'";
$response = mysqli_query($db, $sql);
$result = array();
$result['login'] = array();
if ( mysqli_num_rows($response) === 1 ) {
$row = mysqli_fetch_assoc($response);
if ( password_verify($password, $row['password']) ) {
$index['firstname'] = $row['firstname'];
$index['email'] = $row['email'];
array_push($result['login'], $index);
$result['success'] = "1";
$result['message'] = "success";
echo json_encode($result);
mysqli_close($db);
} else {
$result['success'] = "0";
$result['message'] = "error";
echo json_encode($result);
mysqli_close($db);
}
}
}
?>
答案 0 :(得分：0)
您已使用sessionManager的上下文初始化LoginActivity：
sessionManager = new SessionManager(this);
，然后在SessionManager类中，您可以使用以下代码：
((MainActivity)context).finish();
这将引发错误。
您无法将LoginActivity的上下文转换为MainActivity。
更改为此：
((LoginActivity)context).finish();
毕竟是LoginActivity，您想结束吗？