How to save app data to smartphone?

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To not depend on internet connection, it is possible to save on mobile data related to the app?
For example, when opening for the first time select the language and in the next uses of the app it is not necessary to ask the language, but to search straight from the data that was saved.

java android

  • What kind of data do you want to store?

  • @ramaral would be small data, I edited the question

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2 answers

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In Android development there are several ways to persist the data of an application. One of them is Sharedpreferences, which you can use when you have a small collection of value-keys that you’d like to save (as the android documentation itself says).

Follows the main ways to use Sharedpreferences:

Creating the Sharedpreferences

SharedPreferences pref = getApplicationContext().getSharedPreferences("MinhasPreferencias", MODE_PRIVATE); 
Editor editor = pref.edit();

Storing data as a value key

editor.putBoolean("key_name1", true);           // salvando um boolean - true/false
editor.putInt("key_name2", "int value");        // salvando um integer
editor.putFloat("key_name3", "float value");    // salvando um float
editor.putLong("key_name4", "long value");      // salvando um long
editor.putString("key_name5", "string value");  // salvando uma string

// salva as mudanças no SharedPreferences
editor.apply();

Returning values from Sharedpreferences

// Se o valor da chave não existir, então retornará o segundo parametro
// Você pode armazenar esse retorno em uma variável 
//    Ex: String nome = pref.getString("nome", null);

pref.getBoolean("key_name1", true);         // retornando boolean
pref.getInt("key_name2", 0);             // retornando Integer
pref.getFloat("key_name3", null);           // retornando Float
pref.getLong("key_name4", null);            // retornando Long
pref.getString("key_name5", null);          // retornando String

Deleting unique values Sharedpreferences

editor.remove("key_name3"); // vai deletar a chave key_name3
editor.remove("key_name4"); // vai deletar a chave key_name4

// salva as mudanças no SharedPreferences
editor.apply();

Deleting all information from Sharedpreferences

 editor.clear();
 editor.apply();

One detail: You can save the changes using the method apply() and commit(), differentiating that the apply() is asynchronous.

Here are some links that might be useful:

Developer.Android - Sharedpreferences

Using the Sharedpreferences

Response based on this other answer

Creating Settings Files

  • 2

    Avoid using the.commit() editor as it saves immediately. The.apple() editor will manage the background save by not locking the app processing.

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  • 2

    Could you improve your answer a little bit, so it’s not based purely on a link? Add the save types that exist and how each one behaves?

  • My concern is where to save and if the user will be able to delete this file, I mean if you clear "cache"/"app data" it will be removed? You will have access to the file via usb?

  • Yes of course, I posted quickly because I do it to store games score.

  • Sorry to post another kkk link Felipe Avelar, more has a solution, a stack question : http://stackoverflow.com/questions/10962344/how-to-save-data-in-an-android-app

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