Develop Reference

unable to update values using shared preferences

I am unable to to show updated values in edit text. I have database on server. I am updating user values using retrofit. On server values updates successfully but when i revisit the profile page it shows the values populated from shared preferences. On login i save values in shared preferences and throughout application uses these values.
The code for saving and retrieving the values is below:
Get and set email address in shared preferences
public void putEmail(String loginorout) {
SharedPreferences.Editor edit = app_prefs.edit();
edit.putString(EMAIL, loginorout);
edit.apply();
}
public String getEmail() {
return app_prefs.getString(EMAIL, "");
}
Retrieve values from shared preferences
accountETSU1.setText(preferenceHelper.getEmail());

It's more simple if you create a object called PreferenceHelper, in that object you create a static string for the name of the email like:
final String emailUser = "emailUser";
With that string you create 2 functions one to write:
public void writeEmail(String : email, Context : context){
SharedPreferences sharedPref = context.getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString(emailUser, email);
editor.commit();
}
The other one to get :
public String getEmail(Context : context){
SharedPreferences sharedPref = context.getPreferences(Context.MODE_PRIVATE);
String email = sharedPref.getString(emailUser, "");
return email;
}
Then call the object in your activity
Context context = this#YourActivity;
accountETSU1.setText(PreferenceHelper.getEmail(context));

How to redirect user based on the user's role to different activities in android

I'm new to android development. I would like to create an app with at least 2 user roles. I want the users to be redirected to different activities after their login. I read that it is possible to do that using firebase, but I would not like to use it in my application, since I already started building the app and used retrofit and shared preferences so far. I also found another question her asking the same question and someone answered that it is possible to do so with sessionManager class.
Their answer was:
"Well, I would like to provide my own answer. I actually used Shared Preferences. Its much simple and could globally use the values we put in it. Below is the code:
1. Create a separate class and name it as you wish(I prefer SessionManager here)
public class SessionManager {
// Shared Preferences
SharedPreferences sharedPrefer;
// Editor for Shared preferences
SharedPreferences.Editor editor;
// Context
Context context;
// Shared Pref mode
int PRIVATE_MODE = 0;
// Shared Pref file name
private static final String PREF_NAME = "MySession";
// SHARED PREF KEYS FOR ALL DATA
// User's UserId
public static final String KEY_USERID = "userId";
// User's categoryId
public static final String KEY_CATID = "catId";
// User's categoryType[Teacher, Student, etc.,]
public static final String KEY_CATTYPE = "categoryType";
// User's batchId[like class or level or batch]
public static final String KEY_BATCHID = "batchId";
// Constructor
public SessionManager(Context context) {
this.context = context;
sharedPrefer = context.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
editor = sharedPrefer.edit();
}
/**
* Call this method on/after login to store the details in session
* */
public void createLoginSession(String userId, String catId, String catTyp, String batchId) {
// Storing userId in pref
editor.putString(KEY_USERID, userId);
// Storing catId in pref
editor.putString(KEY_CATID, catId);
// Storing catType in pref
editor.putString(KEY_CATTYPE, catTyp);
// Storing catType in pref
editor.putString(KEY_BATCHID, batchId);
// commit changes
editor.commit();
}
/**
* Call this method anywhere in the project to Get the stored session data
* */
public HashMap<String, String> getUserDetails() {
HashMap<String, String> user = new HashMap<String, String>();
user.put("userId",sharedPrefer.getString(KEY_USERID, null));
user.put("batchId",sharedPrefer.getString(KEY_BATCHID, null));
user.put("catId", sharedPrefer.getString(KEY_CATID, null));
user.put("catType", sharedPrefer.getString(KEY_CATTYPE, null));
return user;
}
}
2. Calling the above methods on some other classes inside the project:
Storing the data in session
SessionManager session = new SessionManager(getApplicationContext());
session.createLoginSession(userId, categoryId, categoryType, batchId);
Retrieving the data from session
SessionManager session = new SessionManager(getApplicationContext());
HashMap<String, String> user = session.getUserDetails();
String userId = user.get("userId").toString();
String categoryId = user.get("catId").toString();
String categoryType = user.get("catType").toString();
String batchId= user.get("batchId").toString();
" - #sam
I'm a bit confused with this answer. I understand the code, but I'm clueless on how could this be used to redirect the users to different activities. Any help and explanation on how to do so would be highly appreciated!

To set a Shared Preference use this code below:
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("ID_NAME_EXAMPLE","STRING_TO_SAVE");
editor.apply();
To access the Shared Preference use this:
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String name = preferences.getString("ID_NAME_EXAMPLE", "DEFAULT_VALUE_IF_NONE");
So for example you can have a Shared Preference saved as WHICH_ACTIVITY
editor.putString("WHICH_ACTIVITY","one");
editor.apply();
Then accesses it when user signs in as
String name = preferences.getString("WHICH_ACTIVITY", "zero");
if(name.equals("zero")){
startActivity(0);
}
else if(name.equals("one")){
startActivity(1);
}

How to make an android app remember my username?

I made a chat room app which asks the user to enter its username every time i open it. How can i make it remember me? I am using fire-base for the back end.
See Code Here

Create Shared Preference class where first time when user enter his/her username store it.
You can read more about Shared Preference here
The for you as follows
public class SharePref {
public static final String PREF_NAME = "chatroom.shared.pref";
public static final String PREF_KEY = "chatroom.shared.username";
public SharePref() {
}
public void save(Context context, String text) {
SharedPreferences sharePref;
SharedPreferences.Editor editor;
sharePref = context.getSharedPreferences(PREF_NAME,Context.MODE_PRIVATE);
editor = sharePref.edit();
editor.putString(PREF_KEY,text);
editor.apply();
}
public String getData(Context context) {
SharedPreferences sharePref;
String text;
sharePref = context.getSharedPreferences(PREF_NAME,Context.MODE_PRIVATE);
text = sharePref.getString(PREF_KEY,null);
return text;
}
}
Now in your MainActivity you can check if you have already stored the username for user
inside your onCreate()
SharePref sharePref = new SharePref();
String UserName = sharePref.getData(mContext);
if(UserName == null) {
String value = //username value;
SharePref sharePref = new SharePref();
sharePref.save(context,value);
}
else {
// you already have username do your stuff
}
Hope this will help

You can use shared preference. Say you are saving username in String called User. To save username:
SharedPreferences shareit = getSharedPreferences("KEY",Context.MODE_PRIVATE);
SharedPreferences.Editor eddy = shareit.edit();
eddy.putString("AKEY", User);
eddy.commit();
And everytime user login:
SharedPreferences sharedPreferences = getContext().getSharedPreferences("KEY", Context.MODE_PRIVATE);
String getName = sharedPreferences.getString("AKEY", "");
String getName will have the value of your username. The "KEY" and "AKEY" used above are to give special id to different values saved via shared preference.

SharedPreferencec prefs = getSharedPreferences("username",Context.MODE_PRIVATE);
SharedPreference.Editor editor = prefs.edit();
if (!prefs.getString("username",null)
//do the chatting
else {
//show dialog to get username
//now save it in shared preferences
editor.putString("username",username);
editor.commit();
}

How to store and retrieve integer using Android Shared Preferences

I am trying to save an integer value and retrieve the value using a same button using shared preferences.
To be more precise, when i click a button the value should be incremented(i++) and then it should be stored. When i close and open the application, it should retrieve the same value from where i left it. How do i do this?
I am using eclipse.

This works for me
public class OnPreferenceManager {
private SharedPreferences.Editor editor;
private SharedPreferences prefs;
private String startHour = "startHour";
private OnPreferenceManager() {}
private OnPreferenceManager(Context mContext) {
prefs = PreferenceManager.getDefaultSharedPreferences(mContext);
editor = prefs.edit();
}
public static OnPreferenceManager getInstance(Context mContext)
{
OnPreferenceManager _app = null;
if (_app == null)
_app = new OnPreferenceManager(mContext);
return _app;
}
public void setStartHour(int hour){
editor.putInt(startHour, hour);
editor.apply();
}
public int getStartHour(){
int selectionStart = prefs.getInt(startHour, -1);
return selectionStart;
}
}
When you need to set integer just write as below
OnPreferenceManager.getInstance(this).setStartHour(theValueYouWantToStore);
And to retrieve write
OnPreferenceManager.getInstance(this).getStartHour()

You can use shared preferences as below.
//To save integer value
SharedPreferences preference = getSharedPreferences("YOUR_PREF_NAME", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putInt("YOU_KEY",you_int_value);
editor.commit();
//To retrieve integer value
SharedPreferences settings = getSharedPreferences("YOUR_PREF_NAME", 0);
int snowDensity = settings.getInt("YOU_KEY", 0); //0 is the default value

Check this gist https://gist.github.com/john1jan/b8cb536ca51a0b2aa1da4e81566869c4
I have created a Preference Utils class that will handle all the cases.
Its Easy to Use
Storing into preference
PrefUtils.saveToPrefs(getActivity(), PrefKeys.USER_INCOME, income);
Getting from preference
Double income = (Double) PrefUtils.getFromPrefs(getActivity(), PrefKeys.USER_INCOME, new Double(10));

Save just an integer into .txt Android

In my application i have to save just an int variable like "score" or "level" so that the progress of the users doesn't go lost.
I tried to parse from a String but it doesn't work for me.
I also tried:
private int readFromFile() {
Scanner getScore= new Scanner(STORETEXT);
punteggio=getScore.nextInt();
return score;
}
where SCORETEXT has been defined:
private final static String STORETEXT = "score.txt";
If i put into the OnCreate:
int points= readfromFIle();
The app crashes.
1) Can you tell me what's the source code to read a Int?
2)I would like to know how to write it to .txt too, just to be sure the code i am using for writing is correct.

You are right in use SharedPreferences. Your app crashes because of empty string resource.
<string name="scoreNow">HERE MUST BE YOUR STRING VALUE</string>
Name attribute in tag is only an identifier, not a value.
But in fact, you shouldn't use strings in resources as key for some value. String resources are needed for localization. Keys for SharedPreferences and same classes better to be constant fields in class. For example, for your code:
public class Storage {
//...
private static final String SCORE_KEY = "score";
public void saveScore(int score) {
SharedPreferences sharedPref = getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putInt(SCORE_KEY, scoreValue);
editor.apply(); //apply is better than commit in fact
}
public int readScore() {
SharedPreferences sharedPref = getPreferences(Context.MODE_PRIVATE);
int scoreValue = sharedPref.getInt(SCORE_KEY, 0);
return scoreValue;
}
}