In the official site of Android, for getPreference() method, it is said that :
Retrieve a SharedPreferences object for accessing preferences that are
private to this activity.
And here(How do I get the SharedPreferences from a PreferenceActivity in Android?) it is said that :
These preferences can only be used within the particular activity and
can not be used by other components of the application.
However, in url http://skillgun.com/android/basics/interview-questions-and-answers/paper/25 5th question,
it is said that it is not guaranteed to be protected as it will be
stored with the name of Activity.
I am confused whether other components of an application(such as activity,service etc.) can access the shared preference created by getPreference() method. is a shared preference created by calling getPreference() method accessible only for an activity for all circumstances?
Basically if you use shared preferences you will be able to read and write the preference from any part of your app. But other apps will not be able to access this information.
The statement regarding not being protected refers to the fact that rooted users (and apps) can read this files from the phone internal storage. So avoid at any cost saving sensitive user information in Shared Preferences. Ex. Dont store userNames, Passwords, personal details, etc.
Use shared preferences for simple things you wish to store Ex. If developing a contacts app you can store whether the user likes to read his contacts firstName LastName or LastName FirstName.
This kind of data is very short and not compromising.
If you require to store sensitive information always encrypt the data first.
Related
If an application has saved data using SharedPreference like this:
SharedPreferences.Editor preferencesEditor = getDefaultSharedPreferences.edit();
preferencesEditor.putInt("count", mValue);
preferencesEditor.apply();
can an other application have access to these data after reboot like this for example:
SharedPreferences sharedPref = getDefaultSharedPreferences();
int value = sharedPref.getInt("count",0);
And if it is not posssible, how is possible from an application to store variable so that other application have access to it?
Yes it is possible, but both apps need to be signed by the same certificates among other things, check this answer for details.
An application can also share and access data from a public content provider and this is usually the recommended way of sharing data among different applications.
You can also have a shared file in storage that both apps can read and write.
I need to use few variables frequently but I want know that which one will give fast response SQLite Database or Shared Preferences ?
Shared Preferences:
What it is?
Shared Preferences is an API from Android SDK to store and retrieve application preferences. Shared Preferences are simply sets of data values that stored persistently. Persistently which mean data you stored in the Shared Preferences are still exist even if you stop the application or turn off the device. SharedPreferences available at the Activity level or shared across all Activity in application package.
When to use Shared Preferences?
o You can use SharedPreferences to save any primitive data: booleans, floats, ints, longs, and strings. This data will persist across user sessions (even if your application is killed).
o Think of a situation where you want to save a small value (Login Credential) that would be referred later sometime when user launches the application. Then shared preference comes into action
How to Use?
SharedPreferences sh_Pref = getSharedPreferences("Login Credentials", MODE_PRIVATE);
Editor toEdit = sh_Pref.edit();
toEdit.putString("Username", "Name");
toEdit.putString("Password", " Password");
toEdit.commit();
SQLite Database:
Android provides several ways to store user and app data. SQLite is one way of storing user data. SQLite is a very light weight database which comes with Android OS.
How to use ?
To use SQLite in Android, a java class should be created as a sub class of SQLiteOpenHelper. This class will act as a database controller which will have the methods to perform the CRUD operations. This custom java class should override the methods named onCreate() and onUpgrade().
onCreate() method will be called for the first time when the Android application is run. First the database instance should be created using the method like getReadableDatabase() or getWritableDatabase() based on the type of access required. Android supports this method by providing in-built methods. For that, SQLiteDatabase class should be used.
What is the purpose of SharedPreferences in Android?
Why it is used ?
Where it want to be use?
Shared preferences is used to save any primitive data: booleans, floats, ints, longs, and strings. This data will persist across user sessions (even if your application is killed).
for more visit here
reference earlier answered
You can read the developer android site about SharedPreference to save light data till your application exists into user's device. It will remain saved even after existing your application.
Storage in android with SharedPreference
SharedPreference in android
Hope it will help you..!!!
SharedPreferences is used to permanently store preferences in key:value pair
SharedPreferences is accessible by all the Activity(ies) of an app. Other app cannot directly access the content of shared_prefs
App stores its data/preferences in the SharedPreferences.
E.g. Say in a game u can store ur score, game level, user name, no of kill, etc in the preferences; so that it is accessible all throughout the game; yet by that particular game only.
Game "Gold Miner 2" does it. It is only one example.
Svox tts save ANDROID_ID in preferences file;
You need to keep in mind that if u delete the app, all SharedPreferences will be deleted (/data/data//shared_prefs);
I want to write a content provider for an app that exposes some data sored in the app's shared preferences. Is it possible to do that?
Why do you want to to do that ? Normally Preferences are secret data which should be only available to source app.
Incase you want to do that, you can read other's app preferences by obtaining the context of source application
Context otherAppsContext = createPackageContext("other.application.package", mode);
Also you should understand that you can’t get all preferences. When you will receive results you will see that PRIVATE and WORLD_WRITABLE aren’t available.
I know this topic has been discussed before on Stack Overflow. But there are still some things that are not clear when I read previous posts about it. So here they are:
I know that we use shared preference for small datasets and sqlite for large data manipulation, so if we just want to save a username and password should we use shared preferences?
Won't shared preferences be lost when user uninstalls the app? For example I download an app called abc and save my username and password. Then I uninstall this app from one phone and try to access it from other phone using the same username and password. Will this be saved using shared preferences or the data be lost?
What are the main reason we use one over the other beside large and small datasets?
You can think of the difference between shared preferences and an SQLite database in terms of data size but that isn't entirely accurate. A better way to think of it is in terms of the structure of the data you want to store.
Shared preferences can only store key-value pairings whilst an SQLite database is much more flexible. So shared preferences are particularly useful for storing user preferences, e.g. should the app display notifications etc. Whilst an SQLite database is useful for just about anything.
Both data sources are local but something you should be aware of is the ability to backup your application data to cloud storage that is linked to the user's Google account. This makes it much easier for your users to change devices and for their applications to easily transfer to the new device. For more info take a look here.
In the situation you described about you will lose the user name and password in both situations. The data is stored on the phone, when you uninstall the application, the data that some with it will also be lost. The user will have to re-enter this information.
You can save the user name and pass in either the shared Preferences or a DB, that is personal preference. Just make sure you lock either down, i.e. don't share the DB or Shared Preferences that you keep this information in.
As for the difference... shared Preferences should hold well... shared Preferences... here is an example:
If I create an option to change the background color, I will store all available options in a DB that can be loaded into a adapter view for the user to choose from. But I will store the color that they have selected in the Shared Preferences. This way when the application load I can get the Shared Preference value of the background color that should be used.
SharedPreferences is used for just that, storing user preferences shared application-wide. You can use it, for example, to store a user's username, or perhaps some options he or she has configured in your app in which you want to remember.
SQLite is a relational database. It's used to store your application's data, not preferences or configuration information.
Both are stored locally on the device.
1.SharedPreferences stores only Boolean, int, float, long, String five kinds of simple data types, such as can not be conditional query. So, whether SharedPreferences data storage operation is how simple it can only be a supplement of storage, but can not completely replace other data such as the SQLite database is stored.
2.SharedPreferences based on the XML file to store key-value key used to store configuration information(mainly user preference for your application).
3.Sharedprefrece just like cookies in web which store some basic information at client side.
both store their data locally, so uninstalling the app will delete both. other than that, SharedPreferences is easier to program, and you're right about the data amounts.
In general, shared preferences should be used if you want to allow your user to directly manipulate certain data fields. Shared preferences are basically user preferences; if you would like the user to reconfigure the app to behave in different ways, you should expose that functionality as a shared preference. On the other hand, the SQLite database should be used if you want to limit the visibility of the data to just the application, if you want a stronger guarantee that the data be persistent, and if you want the application to behave independently of what is stored in the database. Of course, you can use both in one application.
Shared preferences and the database are part of local data that the application stores. If you uninstall the application, both of the data stores will be removed.