Develop Reference

How to check if clear cache was done by user in 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.

Android One-time Login screen using SharedPreferences

I am Wondering about One-time screens... I know, I should use something like SharedPreferences or stuff like that.
If someone has a simple solution for one-time login screen. And a little example.
My login contains: weight, name , height, age and gender (spinner)

You can take a look at Android User info and Sign in :
https://developer.android.com/training/sign-in/index.html
Or you can use login with Facebook API.
Otherwise, I would use Shared prefs.
Create a shared prefs file
SharedPreferences sharedPreferences = getPreferences(Context.MODE_PRIVATE);
This will create a private file for the current activity. You can use MODE_WORLD_READABLE and MODE_WORLD_WRITABLE if it fits your needs.
You can also provide a file name as the first parameter if needed :
SharedPreferences sharedPreferences = getPreferences("com.example.stackoverflow.myfile", Context.MODE_PRIVATE);
Write a shared pref
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("USERNAME", "test");
editor.commit();
You can put any primitive type : int, string, boolean, etc.
It is a key/value set. the key string "USERNAME" will then have a value of "test".
Read shared pref
String username = sharedPreferences.getString("USERNAME", "NO NAME");
The second parameter is a default value to use if the key "USERNAME" didn't get any value.

How to deal with multi accout login in android?

I have several apps which use the same accout.
The question is when i had more than one apps installed in my phone,how can i login without type username and password if one of the app had logged in.

See below reference code which is having app1 & app2, so using shared preferences suppose you can store username & password in app1 & you can using it in another app2. Here I'm shwing how to access username, you can expand it as per your requirement.
Okay! using this code in Application 1 ( with package name is "com.sharedpref1" ) to store data with Shared Preferences.
SharedPreferences prefs = getSharedPreferences("demopref",
Context.MODE_WORLD_READABLE);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("username", strShareValue);
editor.commit();
And using this code in Application 2 to get data from Shared Preferences in Application 1. We can get it because we use MODE_WORLD_READABLE in application 1:
try {
con = createPackageContext("com.sharedpref1", 0);
SharedPreferences pref = con.getSharedPreferences(
"demopref", Context.MODE_PRIVATE);
String data = pref.getString("username", "No Value");
displaySharedValue.setText(data);
} catch (NameNotFoundException e) {
Log.e("Not data shared", e.toString());
}

I think, you could use Database for storing username and password, and share the database among your multiple apps, settings some field like is_logged_in with boolean value 1 when user is loggedin. On app launch, access the database, check for the field is_logged_in and display appropriate logged in view.

How to retrieve name from Edittext for further manipulation?

i have almost completed my game and now i wish to do something with the scores and name so i want to have a high score list...
The problem is that i cannot retrieve the name when i m trying to draw the name using alphabet bitmaps what i have preprared!!!
now the problem occurs when i m tryin to use the getSharedpreferences and m not able to copy the name anywhere in the whole project so that when in the activity of showing the high score i can draw it!!!
is there a simple way to do it please suggest!!!!
thank you!!!

The best way to store a value which will be available all around your application is, as you said, the SharedPreferences.
To store your name user you can do this:
SharedPreferences mPrefs = getSharedPreferences("MyPreferences", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = mPrefs.edit();
editor.putString("username", "your name");
editor.commit();
To retrieve your username you can do this:
SharedPreferences mPrefs = getSharedPreferences("MyPreferences", Context.MODE_PRIVATE);
String username = mPrefs.getString("username", "");

In android how to search that sharedpreference contains some value or not?

In android how to search that sharedpreference contains some value or not?
Actually I m making application which takes password and confirm password as fields.when user start app for first time he must enter both password and confirm password. But i want when user restart that app he must ask to enter only password.
For that i store password in sharedPreferences but now how do i know that their is already password exists in sharedPreferences or not?
so that if their is no password in sharedPreferences i can show the activity which contains both password and confirm password to enter AND if there exists password then i wl show activity that contains only password to enter.
If Anyone have idea then please help me.I m tring from many days but still not getting the output.

You can check it by using the contains method on your SharedPreferences instance:
boolean hasPassword = preference.contains("passwordKey");
API Docs:
public abstract boolean contains (String key)
Since: API Level 1
Checks whether the preferences contains a preference.
Parameters
key The name of the preference to check.
Returns
Returns true if the preference exists in the preferences, otherwise false.

for saving data...
SharedPreferences settings = getSharedPreferences("YourKey", 0);
SharedPreferences.Editor editor = settings.edit();
editor.putString("password", passwordValue);
// Don't forget to commit your edits!!!
editor.commit();
for retrieving...
SharedPreferences settings =this.getSharedPreferences("YourKey", 0);
String userData = settings.getString("password", "0");
if((userData.equals("0"))){
//password has not been saved...
}
else{
//password is already there...
}

fist check if passwort is set:
boolean password_exists = !settings.getString("password","").equals("");
then hide or show the field for the second password
second_passwort_edittext.setVisibility(password_exists ? View.GONE:View.VISIBLE);
After entering the password you can change the behaviour with password_exists (compare the passwords and set them if false, compare with given stored password if true)

I think that you could just validate if you have received something by getting the password value from your shared preferences
if(preferences.getInt("storedPass", 0) != null) {
//Do Stuff
}