Base 64 encode and decode example code

First:

• Choose an encoding. UTF-8 is generally a good choice; stick to an encoding which will definitely be valid on both sides. It would be rare to use something other than UTF-8 or UTF-16.

Transmitting end:

• Encode the string to bytes (e.g. text.getBytes(encodingName))
• Encode the bytes to base64 using the Base64 class
• Transmit the base64

Receiving end:

• Receive the base64
• Decode the base64 to bytes using the Base64 class
• Decode the bytes to a string (e.g. new String(bytes, encodingName))

So something like:

// Sending side
byte[] data = text.getBytes("UTF-8");
String base64 = Base64.encodeToString(data, Base64.DEFAULT);

// Receiving side
byte[] data = Base64.decode(base64, Base64.DEFAULT);
String text = new String(data, "UTF-8");

Or with StandardCharsets:

// Sending side
byte[] data = text.getBytes(StandardCharsets.UTF_8);
String base64 = Base64.encodeToString(data, Base64.DEFAULT);

// Receiving side
byte[] data = Base64.decode(base64, Base64.DEFAULT);
String text = new String(data, StandardCharsets.UTF_8);

For Kotlin mb better to use this:

fun String.decode(): String {
    return Base64.decode(this, Base64.DEFAULT).toString(charset("UTF-8"))
}

fun String.encode(): String {
    return Base64.encodeToString(this.toByteArray(charset("UTF-8")), Base64.DEFAULT)
}

Example:

Log.d("LOGIN", "TEST")
Log.d("LOGIN", "TEST".encode())
Log.d("LOGIN", "TEST".encode().decode())