问题
Can anybody tell me how to maintain session for a user login. For example when the user sign- in to an application they have to be signed in unless the user logouts or uninstall the application similar to gmail in android.
回答1:
Make one class for your SharedPreferences
public class Session {
private SharedPreferences prefs;
public Session(Context cntx) {
// TODO Auto-generated constructor stub
prefs = PreferenceManager.getDefaultSharedPreferences(cntx);
}
public void setusename(String usename) {
prefs.edit().putString("usename", usename).commit();
}
public String getusename() {
String usename = prefs.getString("usename","");
return usename;
}
}
Now after making this class when you want to use it, use like this: make object of this class like
private Session session;//global variable
session = new Session(cntx); //in oncreate
//and now we set sharedpreference then use this like
session.setusename("USERNAME");
now whenever you want to get the username then same work is to be done for session object and call this
session.getusename();
Do same for password
回答2:
You can achieve this by using AccountManager.
Code Sample
// method to add account..
private void addAccount(String username, String password) {
AccountManager accnt_manager = AccountManager
.get(getApplicationContext());
Account[] accounts = accnt_manager
.getAccountsByType(getString(R.string.account_type)); // account name identifier.
if (accounts.length > 0) {
return;
}
final Account account = new Account(username,
getString(R.string.account_type));
accnt_manager.addAccountExplicitly(account, password, null);
final Intent intent = new Intent();
intent.putExtra(AccountManager.KEY_ACCOUNT_NAME, username);
intent.putExtra(AccountManager.KEY_PASSWORD, password);
intent.putExtra(AccountManager.KEY_ACCOUNT_TYPE,
getString(R.string.account_type));
// intent.putExtra(AccountManager.KEY_AUTH_TOKEN_LABEL,
// PARAM_AUTHTOKEN_TYPE);
intent.putExtra(AccountManager.KEY_AUTHTOKEN, "token");
this.setAccountAuthenticatorResult(intent.getExtras());
this.setResult(RESULT_OK, intent);
this.finish();
}
// method to retrieve account.
private boolean validateAccount() {
AccountManagerCallback<Bundle> callback = new AccountManagerCallback<Bundle>() {
@Override
public void run(AccountManagerFuture<Bundle> arg0) {
Log.e("calback", "msg");
try {
Bundle b = arg0.getResult();
if (b.getBoolean(AccountManager.KEY_ACCOUNT_MANAGER_RESPONSE)) {
//User account exists!!..
}
} catch (OperationCanceledException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (AuthenticatorException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
AccountManager accnt_manager = AccountManager
.get(getApplicationContext());
Account[] accounts = accnt_manager
.getAccountsByType(getString(R.string.account_type));
if (accounts.length <= 0) {
return false;
} else {
loginNameVal = accounts[0].name;
loginPswdVal = accnt_manager.getPassword(accounts[0]);
return true;
}
}
回答3:
You can use a boolean value in the SharedPreferences.
Load it before login to check if login is needed.
Save it after login.
回答4:
I have one simple way rather than maintain a session.
i.e. Just store one boolean variable with your username and password. by default set value equal to false.
After first successful login make its value to true.
Then just check its value on your Mainactivity, if it is true then jump to next activity otherwise jump to login activity.
回答5:
Use following code.
SessionManager.java
public class SessionManager {
// Shared Preferences
SharedPreferences pref;
// Editor for Shared preferences
Editor editor;
// Context
Context _context;
// Shared pref mode
int PRIVATE_MODE = 0;
// Sharedpref file name
private static final String PREF_NAME = "Pref";
// All Shared Preferences Keys
private static final String IS_LOGIN = "IsLoggedIn";
// User name (make variable public to access from outside)
public static final String KEY_NAME = "name";
// Email address (make variable public to access from outside)
public static final String KEY_EMAIL = "email";
// Constructor
public SessionManager(Context context){
this._context = context;
pref = _context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
editor = pref.edit();
}
/**
* Create login session
* */
public void createLoginSession(String name, String email){
// Storing login value as TRUE
editor.putBoolean(IS_LOGIN, true);
// Storing name in pref
editor.putString(KEY_NAME, name);
// Storing email in pref
editor.putString(KEY_EMAIL, email);
// commit changes
editor.commit();
}
/**
* Check login method wil check user login status
* If false it will redirect user to login page
* Else won't do anything
* */
public void checkLogin(){
// Check login status
if(!this.isLoggedIn()){
// user is not logged in redirect him to Login Activity
Intent i = new Intent(_context, LoginActivity.class);
// Closing all the Activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
// Add new Flag to start new Activity
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
// Staring Login Activity
_context.startActivity(i);
}
}
/**
* Get stored session data
* */
public HashMap<String, String> getUserDetails(){
HashMap<String, String> user = new HashMap<String, String>();
// user name
user.put(KEY_NAME, pref.getString(KEY_NAME, null));
// user email id
user.put(KEY_EMAIL, pref.getString(KEY_EMAIL, null));
// return user
return user;
}
/**
* Clear session details
* */
public void logoutUser(){
// Clearing all data from Shared Preferences
editor.clear();
editor.commit();
// After logout redirect user to Loing Activity
Intent i = new Intent(_context, LoginActivity.class);
// Closing all the Activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
// Add new Flag to start new Activity
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
// Staring Login Activity
_context.startActivity(i);
}
/**
* Quick check for login
* **/
// Get Login State
public boolean isLoggedIn(){
return pref.getBoolean(IS_LOGIN, false);
}
}
And in MainActivity do like the following.
public class MainActivity extends Activity {
// Email, password edittext
EditText txtUsername, txtPassword;
// login button
Button btnLogin;
// Alert Dialog Manager
AlertDialogManager alert = new AlertDialogManager();
// Session Manager Class
SessionManager session;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
// Session Manager
session = new SessionManager(getApplicationContext());
// Email, Password input text
txtUsername = (EditText) findViewById(R.id.txtUsername);
txtPassword = (EditText) findViewById(R.id.txtPassword);
Toast.makeText(getApplicationContext(), "User Login Status: " + session.isLoggedIn(), Toast.LENGTH_LONG).show();
// Login button
btnLogin = (Button) findViewById(R.id.btnLogin);
// Login button click event
btnLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// Get username, password from EditText
String username = txtUsername.getText().toString();
String password = txtPassword.getText().toString();
// Check if username, password is filled
if(username.trim().length() > 0 && password.trim().length() > 0){
// For testing puspose username, password is checked with sample data
// username = test
// password = test
if(username.equals("test") && password.equals("test")){
// Creating user login session
// For testing i am stroing name, email as follow
// Use user real data
session.createLoginSession("ABC", "abc@gmail.com");
// Staring MainActivity
Intent i = new Intent(getApplicationContext(), MainActivity.class);
startActivity(i);
finish();
}else{
// username / password doesn't match
alert.showAlertDialog(LoginActivity.this, "Login failed..", "Username/Password is incorrect", false);
}
}else{
// user didn't entered username or password
// Show alert asking him to enter the details
alert.showAlertDialog(LoginActivity.this, "Login failed..", "Please enter username and password", false);
}
}
});
}
}
回答6:
Use SharedPreferences. Code to save a value to sharedpreferences:
SharedPreferences sp=getSharedPreferences("key", Context.MODE_PRIVATE);
SharedPreferences.Editor ed=sp.edit();
ed.putInt("value", your_value);
ed.commit();
Code to get value from sharedpreferences:
SharedPreferences sp=getSharedPreferences("key", Context.MODE_PRIVATE);
int value = sp.getInt("value", default_value);
You can check login and logout by using this value.
回答7:
You can obtain that behaivour in a few different ways, the one I prefer is setting a flag in the shared prefs. whe a user logs in an check it when the app is started if you get the default value the user is not loggend, else you should have your flag (i use the user name) set and avoid the log-in section.
回答8:
save the user data in shared preferences till the user logs out. once user logs out clear the data from shared preferences.
回答9:
public class Session {
private SharedPreferences prefs;
public Session(Context cntx) {
// TODO Auto-generated constructor stub
prefs = PreferenceManager.getDefaultSharedPreferences(cntx);
editor = prefs.edit();
}
public void setusename(String usename) {
editor.putString("usename", usename).commit();
}
public String getusename() {
String usename = prefs.getString("usename","");
return usename;
}
}
回答10:
Source Code
https://drive.google.com/open?id=0BzBKpZ4nzNzUcUZxeHo0UnJ5UHc
Fetch Previous Login ID in android
**After Login save Email ID is SharedPreferences**
emaidId = et_Email.getText().toString().trim();
SharedPreferences ss = getSharedPreferences("loginSession_key", 0);
Set<String> hs = ss.getStringSet("set", new HashSet<String>());
hs.add(emaidId);
SharedPreferences.Editor edit = ss.edit();
edit.clear();
edit.putStringSet("set", hs);
edit.commit();
===================onCreate()====================
===================AutoCompleteTextView set Adapter===================
**Fetch PRevious Login Email id in email EditText**
SharedPreferences sss = getSharedPreferences("loginSession_key", 0); // todo loginSession_key key name ALWAYS SAME
Log.i("chauster", "2.set = " + sss.getStringSet("set", new HashSet<String>()));
Log.e("Session", "Value->" + sss.getStringSet("set", new HashSet<String()));
ArrayList<String> al = new ArrayList<>();
al.addAll(sss.getStringSet("set", new HashSet<String>()));
//Creating the instance of ArrayAdapter containing list of language names
ArrayAdapter<String> adapter = new ArrayAdapter<String>
(this, android.R.layout.select_dialog_item, al);
//Getting the instance of AutoCompleteTextView
et_Email.setThreshold(1);//will start working from first character
et_Email.setAdapter(adapter);//setting the adapter data into the
回答11:
Using this class will help you to store all types of sessions
public class Session {
private SharedPreferences prefs;
public Session(Context cntx) {
// TODO Auto-generated constructor stub
prefs = PreferenceManager.getDefaultSharedPreferences(cntx);
}
public void set(String key,String value) {
prefs.edit().putString(key, value).commit();
}
public String get(String key) {
String value = prefs.getString(key,"");
return value;
}
}
来源：https://stackoverflow.com/questions/20678669/how-to-maintain-session-in-android