How to check if clear cache was done by user in android? - android

The app I am developing should know if the user/android* has cleared cache or clear data , so that I logout the user. How to do this? How to find out if user has cleared cache?
Can the android OS clear the cache of an app by itself (without human intervention)?

Use SharedPreference to store value in Application cache
SharedPreference prefs = getSharedPreferences("UserInfo", 0);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("username", username);
editor.putString("password", password);
editor.commit();
when App started Retrieve data from SharedPreference
SharedPreference prefs = getSharedPreferences("UserInfo", 0);
String username = prefs.getString("username","");
String password = prefs.getString("password","");
if cache is cleared SharedPreference also cleared.so you have to make a condition like if username and password empty means not enter Application.

Related

How secure Shared Preferences data in my application from Security Auditor

How to secure SharedPreferences data in my application?.
I use 2 step for this but in Security Audit hacker are able to hack my data.
1 Step-
SharedPreferences sharedPreferences = context.getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("key", value);
editor.commit();
2 Step- Use SecureSharePreferences
SecurePreferences securePrefs = new SecurePreferences(context, "key", "my_user_prefs.xml");
SharedPreferences.Editor editor =securePrefs.edit();
editor.putString(key, value);
editor.commit();
Any other method to handle this.
After read some Answer I update my code with encrypt data but problem still exist.Security auditor still getting application sharedpreference.file from app memory.
SharedPreferences sharedPreferences = context.getSharedPreferences(context.getPackageName(), Context.MODE_PRIVATE);
String keyEncript = EncriptionDecriptionUtils.encriptionOfData(key).toString().trim().replaceAll("\r\n", "");
String value = sharedPreferences.getString(keyEncript, "").trim().replaceAll("\r\n", "");
String valuedecript = EncriptionDecriptionUtils.decriptionOfData(value).toString().trim().replaceAll("\r\n", "");
return valuedecript;
You can encrypt & decrypt the shared preferences data using AES algorithm.If you open shared preferences explicitly you will get encrypted information only.For your reference look into this Securing SharedPreferences Data using AES algorithm
On a rooted phone, it can access the shared preferences for your app. Also, on any phone the user can delete all the data that it's stored in shared preferences by clearing the cache in the application manager. A safe way to store data would be to encrypted it with AES and save it in a text file in the root folder of your app.

How do I save the progress already made in an app?

I'm doing a quiz where the user unlocked the levels, but when he closes the app all progress is lost, and he has to redo everything again. How can I fix this and make the user's progress automatically saved? Or with it by clicking a button, I do not know
You can save it in SharedPreferences and check the value of it every time application is opened.
To save value:
SharedPreferences sp = getSharedPreferences("YourFileName", Context.MODE_PRIVATE); //YourFileName= Any file name you give it
SharedPreferences.Editor editor = sp.edit();
editor.putString("levels", your_level_value); //levels=key at which data is stored, your_level_value=No. of levels completed
editor.apply();
To retrieve value:
SharedPreferences sp = getSharedPreferences("YourFileName", Context.MODE_PRIVATE); //YourFileName= Any file name you give it
String levelCompleted = sp.getString("levels", "0"); //levels=key at which no. of levels is saved.

android cordova sharedpreference deleting during force close

We are facing an issue with android SharedPreferences in our application. Our application is a cordova application. We are storing few data in the SharedPreferences. For example, storing userid, last visited page html contents, few json values.
Following are code samples for managing sharedpreferences (get/set/remove).
//get
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(cordova.getActivity());
Object obj = sharedPrefs.getAll().get(key);
//remove
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(cordova.getActivity());
if (sharedPrefs.contains(key)) {
Editor editor = sharedPrefs.edit();
editor.remove(key);
}
//store
SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(cordova.getActivity());
Editor editor = sharedPrefs.edit();
editor.putString(key, value);
editor.commit();
The storing retrieving deleting everything working fine. The problem we are facing is, the data is not persisting in a consistent manner.
For example, user opens the app and then he force close the app, again takes the app. All data in the sharedpreference is persists. But when he force close 2nd time and come back to the app once again, then the data from the sharedpreference is deleted. I could not find any log in the logcat also. Any help will be much appreciated.

renew facebook access token in android

What is the best way to renew facebook SDK's access token in an Android app?
So far what I've been doing in each splash screen, is to invoke the facebook SDK and to get the access token (if changed or stayed the same, I dont care) and I pass it on to my server.
Is there a less dirty way to accomplish this?
Thanks!
when You first time login then store access token in Sharedprefrence which store value still apk is uninstalled so next time u can get value from shared prefrence
// Create object of SharedPreferences.
SharedPreferences sharedPref= getSharedPreferences("mypref", 0);
//now get Editor
SharedPreferences.Editor editor= sharedPref.edit();
//put your value
editor.putString("accestoken", strName);
//commits your edits
editor.commit();
get value
SharedPreferences sharedPref= getSharedPreferences("mypref", 0);
String access_token=sharedPref.getString("accestoken",null);
if(accesstoken!=null || !accesstoken.equal())
{
}

storing password using shared preference in android

I am using shared preference to store password but when ever my application starts it again ask preference value .i want once i have entered the preference password it should be fixed it should ask me again and again.
Where you want save your password use below code -
Editor editor = getSharedPreferences("password", 0).edit();
editor.putString("password", "your password");
editor.commit();
And where you like to get it back put below code there -
SharedPreferences pref = getSharedPreferences("password", 1);
String password = pref.getString("password", "");
If still its not working, Put your code out here.

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