This is in my main activity class, I can pass and retrieve data in my other class through shared preferences but I cant clear the shared preferences in my other class. Also tell me how to check that my shared preferences are cleared.
SharedPreferences sharedPreferences;
public static final String MyPREFERENCES = "MyPrefs" ;
public static final String Name = "userKey";
public static final String Pass = "passKey";
sharedPreferences=getApplicationContext().getSharedPreferences(MyPREFERENCES,MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString(Name,userName);
editor.putString(Pass,password);
editor.commit();
this is in my other class
SharedPreferences sharedPreferences;
sharedPreferences=getApplicationContext().getSharedPreferences(SignUPActivity.MyPREFERENCES, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.clear();
editor.apply();
editor.commit();
Hi if you want just pass value from one Activity to Another or One Fragment to other than I suggest you to use INTENT to pass data
Look at this example how to pass -http://startandroid.ru/en/lessons/241-lesson-28-extras-passing-data-using-intent.html
Also -https://stackoverflow.com/a/30166602/4741746
sharedPreferences is used when data used for all activity which is permanatly stored in application you also can clear data
Remove given String from shearedPrefrance
public static void removeFromSharedPreferences(Context mContext, String key) {
if (mContext != null) {
SharedPreferences mSharedPreferences = mContext.getSharedPreferences(Constants.SHARED_PREFERENCES_NAME, 0);
if (mSharedPreferences != null)
mSharedPreferences.edit().remove(key).commit();
}
}
Remove All value from SharedPrefrance
public static void removeSharedPreferences(Context mContext) {
if (mContext != null) {
SharedPreferences preferences = mContext.getSharedPreferences("PREFERENCE", 0);
SharedPreferences.Editor editor = preferences.edit();
editor.clear();
editor.commit();
}
}
And why your code is not working is you have to passs Context.MODE_PRIVATE insted MODE_PRIVATE jsut confirm both should have same value
Put this code in both the classes
SharedPreferences app_preferences = PreferenceManager
.getDefaultSharedPreferences(context);
Possible Reason is you are not using the same preferences.
In your first activity you are using:
sharedPreferences = getApplicationContext()
.getSharedPreferences(MyPREFERENCES,MODE_PRIVATE);
And in the other activity you should also use it.
Try to read these
http://developer.android.com/reference/android/app/Activity.html
also from the docs
Retrieve a SharedPreferences object for accessing preferences that are
private to this activity. This simply calls the underlying
getSharedPreferences(String, int) method by passing in this activity's
class name as the preferences name.
Related
My app have mainactivity
User must set a password and it saved in shared prefence like this
settings = getSharedPreferences("NAME", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putString("password", edpassstr);
editor.apply();
I can get this preference in another activity successfully
But I can't get it in the fragment
This is the code used to restore value from shared preference
settings = getActivity().getSharedPreferences("NAME", 0);
String passs = settings.getString("password", "");
The string passs is ="" inside fragment. Why?
How to get the string from shared preference in a fragment?
where are you calling getActivity() in your fragment? Because it will return null when it gets called before the fragment's onAttach method. In your fragment, try overriding the onAttach method, since it gets context as a parameter like so:
#Override
public void onAttach(#NonNull Context context) {
super.onAttach(context);
SharedPreferences settings = context.getSharedPreferences("NAME", 0);
}
If you want to use the shared preferences across the application. You should use applicationcontext instead of lifecycle owners (activity or fragments) context.
applicationcontext.getSharedPreferences(name, mode)
Declare as a global variable
SharedPreferences prefs;
SharedPreferences.Editor editor;
in onCreate() method declare as
prefs = getSharedPreferences("data", MODE_PRIVATE);
editor = getSharedPreferences("data", MODE_PRIVATE).edit();
editor.putString("password", "xyz_password");
editor.apply();
You can get the value from shared preference using this way
prefs.getString(key,default Value);
prefs.getString("password", "Any value if you not get any value");
It's so easy I hope it's helpful to you...!
I know this has been asked before, but i can't seem to figure it out
i am trying to get my preferences by this:
SharedPreferences preferences = this.getActivity().getSharedPreferences("storedName", Context.MODE_PRIVATE);
String loginemail = preferences.getString("storedName", "");
but this doesn't seem to work, i have multiple sharedPreferences which i need to get in my fragment what is the correct way to do it?
As getDefaulSharedPreferences(this) doesn't work.
i store my prefs like so:
savePreferences("shareUniqePass", uniqePassIds.getText().toString());
savePreferences("storedName", inputEmail.getText().toString());
savePreferences("Storedpass", inputPassword.getText().toString());
private void savePreferences(String key, boolean value){
SharedPreferences sharedPreferences = PreferenceManager
.getDefaultSharedPreferences(this);
Editor checkbox = sharedPreferences.edit();
checkbox.putBoolean(key, value);
checkbox.commit();
}
private void savePreferences(String key, String value){
SharedPreferences sharedPreferences = PreferenceManager
.getDefaultSharedPreferences(this);
Editor names = sharedPreferences.edit();
names.putString(key, value);
names.commit();
}
Instead of getting it from getSharedPreferences use the getDefaultSharedPreferences.
As getDefaulSharedPreferences(this) doesn't work.
You used getDefaultSharedPreferences for saving the data and therefore you must use getDefaultSharedPreferences to get the data that was saved.
this mean the instance of your fragment instead use the getActivity() to get the instance of context from your activity.
sample:
String loginemail = PreferenceManager.getDefaultSharedPreferences(getActivity()).getString(PREF_USER_NAME, "");;
You need to make sure that your saving and loading the data from the same shared preferences. If you're only accessing it from the one activity / fragment, you should use getDefaulSharedPreferences(this).
If, however, you're going to use it from several different activities / fragments, you should use:
private void savePreferences(String key, boolean value){
SharedPreferences prefs = getActivity().getSharedPreferences("storedName", Context.MODE_PRIVATE);
Editor checkbox = sharedPreferences.edit();
checkbox.putBoolean(key, value);
checkbox.commit();
}
I am new to android..and I'm developing an application using Json. I want to pass a string value from my main activity to another class without starting the activity class. I heard there is some way using shared preferences. I just tried.. but didn't worked..i got null point exception.. here is my code...
confirm = check.AuthenticateUser(name, passwd);
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = preferences.edit();
editor.putString("Name",confirm);
editor.commit();
here is the place i want to send the value of "confirm" (string variable)
and below code shows where i want to get that preference..actually that class named "ShortList".
here is the code where i trying to get the value
public class ShortList extends Activity {
//ArrayList<HashMap<String, String>> arl;
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String cargivr = preferences.getString("Name","");
please some one help me..
public static String CREDENTIALS_FILENAME = "com.myapp.credentials";
public static String PIN = "pin";
public static void writeCredentials(Context c,String pin) {
SharedPreferences credentialsPref = c.getSharedPreferences(CREDENTIALS_FILENAME, 0);
SharedPreferences.Editor editor = credentialsPref.edit();
editor.putString(PIN, pin);
editor.commit();
}
public static String readCredentials(Context c,String pin) {
SharedPreferences credentialsPref = c.getSharedPreferences(CREDENTIALS_FILENAME, 0);
SharedPreferences.Editor editor = credentialsPref.edit();
return credentialsPref.getString(PIN, "default value");
}
MainActivity.java
SharedPreferences pref = getApplicationContext().getSharedPreferences("New",Context.MODE_PRIVATE);
Editor edit = pref.edit();
edit.putString("SomeKey", "SomeValue");
edit.commit();
SecondActivity.java
SharedPreferences prefs = getApplicationContext().getSharedPreferences("New",Context.MODE_PRIVATE);
String value = prefs.getString("SomeKey","DefaultValue");
Also make sure that you have added the second activity details in your android manifest file -
<activity
android:name="com.example.projectName.SecondActivity"
android:parentActivityName="com.example.sharedpref.MainActivity">
</activity>
public class ShortList extends Activity {
//ArrayList<HashMap<String, String>> arl;
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String cargivr = preferences.getString("Name","");
Here it seems you're initializing member variables.
You cannot use an Activity as a Context until onCreate() in the activity lifecycle. Member variable initialization is too early and will usually lead to NPE in getBaseContext().
Move the initialization of preferences and cargivr to onCreate() or later.
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(ShortList.this);
String cargivr = preferences.getString("Name","");
I have SharedPreferences in main activity like this :
public class MainActivity extends SherlockFragmentActivity {
public void showUserSettings() {
SharedPreferences sharedPrefs = PreferenceManager
.getDefaultSharedPreferences(getApplicationContext());
Editor editor= sharedPrefs.edit();
editor.putString("userFormat", sharedPrefs.getString("example_list", "2"));
editor.commit();
}
now I wanna get value from SharedPreferences but in bellow class :
public class ReadFormatSharePerf extends Activity {
private DecimalFormat df;
public String finalFormat(String finalFormat) {
SharedPreferences sharedPrefs = PreferenceManager
.getDefaultSharedPreferences(getApplicationContext());
String customFormat = sharedPrefs.getString("userFormat", "#.##");
df = new DecimalFormat(customFormat);
String result = df.format(finalFormat);
return result;
}
I called above activity like this code :
public class Angles {
...
...
ReadFormatSharePerf my= new ReadFormatSharePerf();
result=my.finalFormat(String.valueOf(finalValue));
}
I caught error :
10-16 15:57:24.035: E/AndroidRuntime(10792): java.lang.NullPointerException
atandroid.content.ContextWrapper.getApplicationContext(ContextWrapper.java:101)
how I can do it ?
You should not be instantiating your Activity objects with new. Instead, either make the class not inherit from Activity, or instantiate it via Intent.
The NPE comes from trying to use an Activity as a Context before its onCreate() i.e. in a constructor or a member variable initializer. If you're using the Intent-based instantation, move the code that requires a Context to onCreate() or later in the activity lifecycle. If you make the class not an Activity, pass in a Context reference from caller.
Instead, do:
SharedPreferences sharedPrefs = PreferenceManager
.getDefaultSharedPreferences(this);
This code snippet will help you and Shared Preference KEY values must be same
Saving the values
SharedPreferences preferences = getSharedPreferences("MY_SHARED_PREF",0);
SharedPreferences.Editor editor = preferences.edit();
editor.putInt(String.valueOf(key), value);//store int values, can use string,arrays,etc
editor.commit();
Try to use this
Load the saved values
SharedPreferences getProgramPrefs = this.getSharedPreferences(
"MY_SHARED_PREF", MODE_WORLD_READABLE);
int Index = getProgramPrefs.getInt(String.valueOf(key), -1);
Problem: Activity B ALWAYS return false, however, if I check the same KEY inside activity A, the result is true. Why is this? I have checked the KEY, it is exactly the same in both activities.
Edit: Thank you all for your help, however after implementing your suggestions, I still have had no luck. Here is what I have now:
ActivityA, extends Activity Implements OnGesturePerformedListener
//How methods are called...
read(getApplicationContext(),"fav", posName);
write(getApplicationContext(), "fav", posName, false);
...
public Boolean read(Context context, String name, String key) {
SharedPreferences sP = context.getSharedPreferences(name, MODE_PRIVATE);
Boolean b = sP.getBoolean(key, false);
return b;
}
public void write(Context context, String name, String key, boolean value) {
SharedPreferences sP = context.getSharedPreferences(name, MODE_PRIVATE);
SharedPreferences.Editor editor = sP.edit();
editor.putBoolean(key, value);
editor.commit();
}
ActivityB, extends FragmentActivity, sub class:
public static class SectionFragment extends Fragment
Inside onActivityCreated()
SharedPreferences sP = getActivity().getSharedPreferences("fav", MODE_PRIVATE);
Boolean b = sP.getBoolean(posName, false);
Results = b always equals false
Any Ideas?
Use getSharedPreferences`:
public void write(Context context, String key, boolean value) {
SharedPreferences sharedPreferences = context.getSharedPreferences(
NAME_SHAREDPREFERENCES, MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putBoolean(key, value);
editor.commit();
}
public Boolean read(Context context, String key) {
SharedPreferences sharedPreferences = context.getSharedPreferences(
NAME_SHAREDPREFERENCES, MODE_PRIVATE);
Boolean b = sharedPreferences.getBoolean(key, false);
return b;
}
From the Android docs:
Activity persistent state is managed with the method getPreferences(int), allowing you to retrieve and modify a set of name/value pairs associated with the activity. To use preferences that are shared across multiple application components (activities, receivers, services, providers), you can use the underlying Context.getSharedPreferences() method to retrieve a preferences object stored under a specific name.
(http://developer.android.com/reference/android/app/Activity.html)
So basically you need to use Context.getSharedPreferences() to share preferences across multiple activities.
You can adopt the following approach to get same sharedPreference everywhere:
SharedPreference mPrefs = PreferenceManager.getDefaultSharedPreference(getApplicationContext());
SharedPreference.Editor mEditor = mPrefs.edit();
I hope it was useful.