I'm a novice Android developer who are currently trying hard to build a Login Screen.
I need to find the easiest way to store the username and password in 1 class and retrieve it from another class. See Google has provided several ways: http://developer.android.com/guide/topics/data/data-storage.html
which one is the most efficient and easy to code?
thanks!
For Login screen tasks like storing username and password you can use Shared Preferences. Here I had made custom methods for using shared preferences. Call savePreferences() method and put your Key and Value(as savePreferences() is based on XML), similarly call Load with your Key. And lastly don't forgot to call deletePreferences() on LOGOUT.
/**
* Method used to get Shared Preferences */
public SharedPreferences getPreferences()
{
return getSharedPreferences(<PREFRENCE_FILE_NAME>, MODE_PRIVATE);
}
/**
* Method used to save Preferences */
public void savePreferences(String key, String value)
{
SharedPreferences sharedPreferences = getPreferences();
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(key, value);
editor.commit();
}
/**
* Method used to load Preferences */
public String loadPreferences(String key)
{
try {
SharedPreferences sharedPreferences = getPreferences();
String strSavedMemo = sharedPreferences.getString(key, "");
return strSavedMemo;
} catch (NullPointerException nullPointerException)
{
Log.e("Error caused at TelaSketchUtin loadPreferences method",
">======>" + nullPointerException);
return null;
}
}
/**
* Method used to delete Preferences */
public boolean deletePreferences(String key)
{
SharedPreferences.Editor editor=getPreferences().edit();
editor.remove(key).commit();
return false;
}
Define some statics to store the preference file name and the keys you're going to use:
public static final String PREFS_NAME = "MyPrefsFile";
private static final String PREF_USERNAME = "username";
private static final String PREF_PASSWORD = "password";
You'd then save the username and password as follows:
getSharedPreferences(PREFS_NAME,MODE_PRIVATE)
.edit()
.putString(PREF_USERNAME, username)
.putString(PREF_PASSWORD, password)
.commit();
So you would retrieve them like this:
SharedPreferences pref = getSharedPreferences(PREFS_NAME,MODE_PRIVATE);
String username = pref.getString(PREF_USERNAME, null);
String password = pref.getString(PREF_PASSWORD, null);
if (username == null || password == null) {
//Prompt for username and password
}
Alternatively, if you don't want to name a preferences file you can just use the default:
SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(this);
For your purpose both, SQLite Database and SharedPreferences will work. But I would suggest SharedPreferences as they are very easy to use. Some ppl like to create a class to hold variables like this but the benefit of SQLite and SharedPreferences file is that the user login name and password information will be with you even if the app goes in background and gets destroyed. So when the user comes back to your app, you can sign them in again without asking for password. If user explicitly decides to logout, you can simply remove the login information from shared preferences file
The easiest way of retrieving log in information from other activities is using "SharedPreferences". I strongly recommend this method for storage and retrieval of Username and Password. Because you can access this information from anywhere in the application without any complications. The log in information may have to use repeatedly in an application.
Many applications may provide a way to capture user preferences on the settings of a specific application or an activity. For supporting this, Android provides a simple set of APIs.
Preferences are typically name value pairs. They can be stored as “Shared Preferences” across various activities in an application (note currently it cannot be shared across processes). Or it can be something that needs to be stored specific to an activity.
Shared Preferences: The shared preferences can be used by all the components (activities, services etc) off the applications.
Activity handled preferences: These preferences can only be used with in the activity and can not be used by other components of the application.
Shared Preferences:
The shared preferences are managed with the help of the getSharedPreferences method of the Context class. The preferences are stored in a default file(1) or you can specify a file name(2) to be used to refer to the preferences.
(1) Here is how you get the instance when you specify the file name
public static final String PREF_FILE_NAME = "PrefFile";
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
MODE_PRIVATE is the operating mode for the preferences. It is the default mode and means the created file will be accessed by only the calling application. Other two mode supported are MODE_WORLD_READABLE and MODE_WORLD_WRITEABLE. In MODE_WORLD_READABLE other application can read the created file but can not modify it. In case of MODE_WORLD_WRITEABLE other applications also have write permissions for the created file.
(2) The recommended way is to use by the default mode, without specifying the file name:
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
Finally, once you have the preferences instance, here is how you can retrieve the stored values from the preferences:
int storedPreference = preferences.getInt("storedInt", 0);
To store values in the preference file SharedPreference.Editor object has to be used. Editor is the nested interface of the SharedPreference class.
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", storedPreference); // value to store
editor.commit();
Editor also support methods like remove() and clear() to delete the preference value from the file.
Activity Preferences:
The shared preferences can be used by other application components. But if you do not need to share the preferences with other components and want to have activities private preferences. You can do that with the help of getPreferences() method of the activity. The getPreference method uses the getSharedPreferences() method with the name of the activity class for the preference file name.
Following is the code to get preferences:
SharedPreferences preferences = getPreferences(MODE_PRIVATE);
int storedPreference = preferences.getInt("storedInt", 0);
The code to store values is also same as in case of shared preferences.
SharedPreferences preferences = getPreference(MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putInt("storedInt", storedPreference); // value to store
editor.commit();
You can also use other methods like storing the activity state in database. Note Android also contains a package called android.preference. The package defines classes to implement application preferences UI.
To see some more examples check Android's Data Storage post on developers site.
For more info, check this link:
Making data persistent in android
Related
I have a Sharedpreferences to check if the user has activated the pro section with InAppPurchase and I check it every time Mainactivity is opens, like this:
SharedPreferences s = c.getSharedPreferences("app" , MODE_PRIVATE);
String value = s.getString(key , " ");
Log.i("myapp" , value);
and if some one tries to change the value manually my app warns him .so I tried to test my app's security and changed the value manually with text editor from data/data/com.myapp.package/shared_prefs/ let's say the value was 39m49ur3.I changed it a to 87mjr83.Then I started the app and the value from the logs stil was 39m49ur3 . I closed the app and started it again but no change was seen except when I clear the RAM of my device then start the app , finally then the value I got from the logs is what really is in the shared_prefs folder.
What can I do about this?
Save like this,
SharedPreferences pref = c.getSharedPreferences("app", MODE_PRIVATE);
Editor editor = pref.edit();
editor.putString("myapp", "string value");
editor.commit();
Get Like this,
pref.getString("myapp", null);
//to save String in shared preferences
public void put(String key, String value) {
mSharedPreferences.edit().putString(key, value).apply();
}
//to get value from shared preferences
public String get(String key, String defaultValue) {
return mSharedPreferences.getString(key, defaultValue);
}
Try to use
editor.apply();
Instead of
editor.commit();
Unlike commit(), which writes its preferences out to persistent storage synchronously, apply() commits its changes to the in-memory SharedPreferences immediately but starts an asynchronous commit to disk and you won't be notified of any failures.
I want to know if there is a way to pass all the extras to the new intent.
Is it possible? And is it a good idea?
The reason is that I want to save the login state as a json string, and pass it in between Activities. I don't want to store data with SQLite or anything. Can I bypass all the intent extras to the new intent ?
please consider Shared Preference :
// Declaration
public static String KEY = "SESSION";
public static void saveUserName(String username, Context context) {
Editor editor = context
.getSharedPreferences(KEY, Activity.MODE_PRIVATE).edit();
editor.putString("username", username);
editor.commit();
}
public static String getUserName(Context context) {
SharedPreferences savedSession = context.getSharedPreferences(KEY,
Activity.MODE_PRIVATE);
return savedSession.getString("username", "");
}
You can store the login credentials to preference and retrieve them as well in any of your activity.
SaveUsername("Your text to save", Your_activity.this);
And to retrieve the value
String mUserName = getUserName(YourActivity.this);
It is recommended to have all your preference methods in your utils class to keep the code organized.
You can read more here
yes you can use Shared Preference to save the Login session of user here is handy example of managing session using shared preference http://www.androidhive.info/2012/08/android-session-management-using-shared-preferences/ I used it earlier and suggest you to have a look at it.
Any of the two may help you.
Saving it in the sharedPreference file.
If you want them to be accessable throught the application you can use the applicationClass, like a global singleton.
I want to know if its possible to keep information about an app in a while for example.
I have an app that access this file and get information about the choices that the user have made. For example:
I have a button for many events (event is a model), and i want to know if the user clicked in the button even after the application restarts.
I know that it is possible to keep information about login and password. Is possible to do something like this with other information?
Use Shared Preferences. Like so:
Create these methods for use, or just use the content inside of the methods whenever you want:
public String getPrefValue()
{
SharedPreferences sp = getSharedPreferences("preferenceName", 0);
String str = sp.getString("myStore","TheDefaultValueIfNoValueFoundOfThisKey");
return str;
}
public void writeToPref(String thePreference)
{
SharedPreferences.Editor pref =getSharedPreferences("preferenceName",0).edit();
pref.putString("myStore", thePreference);
pref.commit();
}
You could call them like this:
// when they click the button:
writeToPref("theyClickedTheButton");
if (getPrefValue().equals("theyClickedTheButton"))
{
// they have clicked the button
}
else if (getPrefValue().equals("TheDefaultValueIfNoValueFoundOfThisKey"))
{
// this preference has not been created (have not clicked the button)
}
else
{
// this preference has been created, but they have not clicked the button
}
Explanation of the code:
"preferenceName" is the name of the preference you're referring to and therefore has to be the same every time you access that specific preference. eg: "password", "theirSettings"
"myStore" refers to a specific String stored in that preference and their can be multiple.
eg: you have preference "theirSettings", well then "myStore" could be "soundPrefs", "colourPrefs", "language", etc.
Note: you can do this with boolean, integer, etc.
All you have to do is change the String storing and reading to boolean, or whatever type you want.
You can use SharedPreference to save your data in Android.
To write your information
SharedPreferences preferences = getSharedPreferences("PREF", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("user_Id",userid.getText().toString());
editor.putString("user_Password",password.getText().toString());
editor.commit();
To read above information
SharedPreferences prfs = getSharedPreferences("PREF", Context.MODE_PRIVATE);
String username = prfs.getString("user_Id", "");
In iOS NSUserDefaults is used to do the same
//For saving
NSUserDefaults *defaults=[NSUserDefaults standardUserDefaults];
[defaults setObject:your_username forKey:#"user_Id"];
[defaults synchronize];
//For retrieving
NSString *username = [defaults objectForKey:#"user_Id"];
Hope it helps.
i am creating login in my app. User type his info i send it to web service to check and get his ID. Now i need to save it somewhere in my app that i could check if he had login.
So where this info should be saved ? I know that every app have it's settings so there should be this info ? Maybe someone could give me more info what and how this is doing.
Thanks.
I found this post:
What is the most appropriate way to store user settings in Android application
I believe my question was duplicate. But it would be nice if you have something to share more.
First of all save user info like uname & password in SharedPreferences with this code.
SharedPreferences settings = getSharedPreferences("UserInfo", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putString("Username",txtUname.getText().toString());
editor.putString("Password",txtPWD.getText().toString());
editor.commit();
and then get SharedPreferences from below code
SharedPreferences settings = getSharedPreferences("UserInfo", 0);
txtUname.setText(settings.getString("Username", "").toString());
txtPWD.setText(settings.getString("Password", "").toString());
Answer is Use Application Class or Shared Preferences
I assume you can easily search for the Example of Application Class, SharedPreferences and SQLite Database
So I am mentioning Where Do I Use Which Options
Application Class
When I got anything(var , array , list , objects) to store just only for the LifeTime of the Application..and As it got close (for Android Force Close) I use Application Class.
SharedPreferences
I use this when I got some short information like id,token,username,flags and I want to store that as long as the application rest in the Device..and need to use those information everytime I start the Application..
SQLite Database
When there is a bulk data in Record format (Row - Column) I used it to store in database so it becomes easy to store , retrive and manipulate.
You can use SharedPreferences for this.
Some codes from references (taken from documentation):
public class Calc extends Activity {
public static final String PREFS_NAME = "MyPrefsFile";
#Override
protected void onCreate(Bundle state){
super.onCreate(state);
. . .
// Restore preferences
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
boolean silent = settings.getBoolean("silentMode", false);
setSilent(silent);
}
#Override
protected void onStop(){
super.onStop();
// We need an Editor object to make preference changes.
// All objects are from android.context.Context
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
SharedPreferences.Editor editor = settings.edit();
editor.putBoolean("silentMode", mSilentMode);
// Commit the edits!
editor.commit();
}
}
if user clear the application data from setting -> application manager -> your application -> clear data
then all data saved in shared preferences will get removed
I have an Android application in which I have my preferences in an XML file, which works fine. I now want to set one of the preferences using code instead of displaying the entire preference screen, how would I go about doing this?
I assume by preferences you are referring to your application's preferences and not Android phone settings.
To store preferences between runs of you application you need to do the following
Create a SharedPreferences object
SharedPreferences settings = getSharedPreferences(String n, MODE_PRIVATE);
String n identifies your preferences and the second argument is the mode they'll be accessed
Instantiate an Editor object
SharedPreferences.Editor editor = settings.edit();
Note: do not try settings.editor.edit(), this will not make a persistent object and the code below will not work
Write your preferences to the buffer
editor.put...(String, value)
There are numerous put function, putString, putBoolean, etc. The String is the key ("version", "good run") and the value is the value ("1.5.2", true)
Flush the buffer
editor.commit();
This actually writes you put to the preferences. If your app crashes before this line then the preferences will not be written. There is also a documented bug: commit() is supposed to return a boolean indicating success or failure. Last I checked it always returned false.
These preferences will by stored on the phone and will only be accessible to your application.
More documentation is here
I tried this but didn't work:
SharedPreferences settings = getSharedPreferences(String n, MODE_PRIVATE);
Try this instead:
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this);
You can save something in the sharedpreferences by using below code
public static void save(String valueKey, String value) {
SharedPreferences prefs = PreferenceManager
.getDefaultSharedPreferences(context);
SharedPreferences.Editor edit = prefs.edit();
edit.putString(valueKey, value);
edit.commit();
}
To read preferences:
public static String read(String valueKey, String valueDefault) {
SharedPreferences prefs = PreferenceManager
.getDefaultSharedPreferences(context);
return prefs.getString(valueKey, valueDefault);
}