Saving byte array using SharedPreferences in java

Saving byte array using SharedPreferences in java

In Android, you can save a byte array using SharedPreferences, but you need to convert the byte array to a Base64-encoded string before saving it, as SharedPreferences only supports primitive data types for storage. Here's how you can save and retrieve a byte array using SharedPreferences:

  1. Convert Byte Array to Base64 String:

    Before saving the byte array, you need to convert it to a Base64-encoded string:

    import android.util.Base64; // Convert a byte array to a Base64-encoded string public String byteArrayToBase64(byte[] byteArray) { return Base64.encodeToString(byteArray, Base64.DEFAULT); } // Convert a Base64-encoded string back to a byte array public byte[] base64ToByteArray(String base64String) { return Base64.decode(base64String, Base64.DEFAULT); }

  2. Save and Retrieve the Base64 String Using SharedPreferences:

    Once you have the Base64-encoded string, you can save and retrieve it using SharedPreferences:

    import android.content.Context; import android.content.SharedPreferences; public class MyPreferences { private static final String PREF_NAME = "MyPreferences"; private static final String KEY_BYTE_ARRAY = "byteArrayKey"; private SharedPreferences sharedPreferences; public MyPreferences(Context context) { sharedPreferences = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE); } // Save a byte array to SharedPreferences public void saveByteArray(byte[] byteArray) { String base64String = byteArrayToBase64(byteArray); SharedPreferences.Editor editor = sharedPreferences.edit(); editor.putString(KEY_BYTE_ARRAY, base64String); editor.apply(); } // Retrieve a byte array from SharedPreferences public byte[] getByteArray() { String base64String = sharedPreferences.getString(KEY_BYTE_ARRAY, null); if (base64String != null) { return base64ToByteArray(base64String); } return null; // If no data is found, return null or an empty byte array as needed } }

  3. Usage Example:

    You can use the MyPreferences class to save and retrieve a byte array as follows:

    // Initialize preferences MyPreferences myPreferences = new MyPreferences(context); // Save a byte array byte[] byteArrayToSave = ...; // Your byte array myPreferences.saveByteArray(byteArrayToSave); // Retrieve the byte array byte[] retrievedByteArray = myPreferences.getByteArray(); // Use the retrieved byte array if (retrievedByteArray != null) { // Do something with the retrieved byte array }

By encoding the byte array as a Base64 string and then storing it in SharedPreferences, you can save and retrieve byte arrays in Android applications.

More Tags

backend libusb-1.0 ply divide-by-zero pull-to-refresh pushsharp picasso sonarlint computation-theory fluent

More Java Questions

More Statistics Calculators

More Retirement Calculators

More Electrochemistry Calculators

More Gardening and crops Calculators