When unit testing shared preference, is the value get refresh every test?
public static void putString(Context context, String key, String val) {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor = prefs.edit();
editor.putString(key, val);
editor.apply();
}
Once you run your function it will save the val under the key which will be saved for every other instance. If you want to be absolutely be sure of this, you can read the value using another function (and maybe a different instance) usingPreferenceManager.getDefaultSharedPreferences(context.getString(key, "default"));
Alternatively, like many have said, you can manually check the default SharedPreferences file located in /data/data/YOUR_PACKAGE_NAME/shared_prefs/YOUR_PACKAGE_NAME_preferences.xml inside your app data folder, on the device you are testing on.
The shared preference does not get cleared until you clear the editor. Make sure when you are testing the screen again, the editor is not getting cleared. Only then the preference may get cleared out.
To access the shared.xml folder, you can follow this link
How can I view the shared preferences file using Android Studio?
Related
How can I make data available through my whole android app?
For instance, I want to display a user picture in the toolbar in every screen. Also, the name of the user is displayed in the navigation drawer in every screen.
Is a singleton the right approach for this? Or are other techniques better?
I have been googling a lot, but i can't find a good approach for my use case so far.
To use shared preferences:
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = preferences.edit();
to save in shared preferences:
editor.putString("tag", "save me please");
editor.apply();
to retrieve from shared preferences:
String s = preferences.getString("tag", "default_value");
Notes:
You can make your tags as string constants to make sure you are always using the same value.
If you use the editor for multiple values, always remember to add editor.apply() in the end, to actually apply your changes.
If you want the editor to write the changes synchronously, use editor.commit() instead. You can save any type of variable in the shared preferences, just use the appropriate method (instead of putString use putInt, putLong, etc - same with the getSring). More on Shared Preferences in the API here
I am trying an application where I am using Shared Preference. When I delete the preference file from data/data/com.your.package.name/shared_prefs/mySharedPref.xml manually using Android monitor, still the app is able to read the preference values.
I am assuming that some how the value is retained in main memory of the phone. Am I correct & what is the viable solution to clear shared preferences totally leaving no traces. But one thing I want to clear preference only if the file is wiped. For this I need to check presence of file, Any other approach rather than checking with File class ?
I think this code must work
public static void clearAllPreference(Context context){
SharedPreferences prefs = context.getSharedPreferences(PREF_FILE, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.clear();
editor.commit();
}
To remove specific values: SharedPreferences.Editor.remove() followed by a commit()
To remove them all SharedPreferences.Editor.clear() followed by a commit()
You use remove() to remove specific preferences, you use clear() to remove them all.
Checkout official documentation on SharedPreferences.Editor.
In my application,there are some application specific settings, which should be available to me , next time when my application starts up.
In other words i want the data to be available across the sessions of an application cycle.
Can this be achieved without using database(sqlite).
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 file, that can be either a custom one (1) or the default file (2).
(1) Here is how you get the instance when you want to 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.
You should use shared preferences:
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
prefs.edit().putString("my_pref", "my_value").commit();
And to retrieve it:
String value = prefs.getString("my_pref", "default Value");
These preferences are persistent, and are also integrated with the preference activities.
(I'm Coming from a C# background writing iPhone apps with MonoTouch)
I have a simple app that needs to save button color. I have this code in a Settings class that is a singleton.
Is this the way it 'should' be done? I usually like having a single Setting instance that is accessed around the app in my C# iPhone apps.
private static Bundle bundle = new Bundle();
public static int getButtonColor() {
return bundle.getInt("buttonColor", RED_BUTTON) ;
}
public static void setButtonColor(int SettingButtonColor) {
bundle.putInt("buttonColor", SettingButtonColor);
}
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 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 = PreferencesManager.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.
You probably want to look at setting SharedPreferences
i am trying to store the user preference of whether the checkbox is clicked or not in an Activity , but when i shutdown and restart the app, i don't get the desired result . i.e if the user had checked the checkbox then on restarting i am not getting it as checked.
here's what i have tried:
public void onCreate()
{
....
checkbox=(CheckBox)findViewById(R.id.checkbox);
// storing the user preference
SharedPreferences sharedpref = getSharedPreferences(MYPREF,Activity.MODE_PRIVATE); //here MYPREF is the name of the file storing the preference
SharedPreferences.Editor e = sharedpref.edit();
e.putBoolean("checkboxvalue", checkbox.isChecked());
e.commit();
//retrieving the preference set
SharedPreferences mysharedpref = getSharedPreferences(TextSpeaker.MYPREF,Activity.MODE_PRIVATE);
checked=mysharedpref.getBoolean("checkboxvalue", false);
if(checked)checkbox.setChecked(true);
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 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 = PreferencesManager.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.
You are working with two separate preference data files, in all likelihood, since it would appear that you have two different components (e.g., activities).
Try switching to using getDefaultSharedPreferences() (available on PreferenceManager) instead of getSharedPreferences(), and see if that helps.
Hi Pranay if you created before your preference with the same name in other activity or app you will have problems reading the same preference change to MODE_WORLD_READABLE
getSharedPreferences(MYPREF,Activity.MODE_WORLD_READABLE);
or
getSharedPreferences(MYPREF,1);