Using shared preferences between unity and native android sdk

Question

I am working on an app using native android sdk development. However I have a co-worker who is working on Unity.

I would like to create an activity A that would does some work and then call another activity B.

My coworker is creating Activity B screen using Unity.

Both activities will be using shared preferences (reading and writing to it)

Is there way that this can be accomplished?

Thank you so much

Answer 1

You'd need to write a plugin for Android to get this to work. While the official doc is great to get started, here's some sample code you can use after you've gone through it.

I won't go into details about how to create the plugin, because that's pretty well documented on the Unity website (link given by nexx)

In the below example, I've just written a couple of methods. You can modify them to accept and return other data types, or better make them generic.

Native Android Code

public static final String PREFS_NAME = "MyPrefsFile";

public void setPreferenceString (String prefKey, String prefValue) {
    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
    SharedPreferences.Editor editor = settings.edit();
    editor.putString(prefKey, prefValue);
    editor.commit();

}

public String getPreferenceString (String prefKey) {
    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
    String playerName = settings.getString(prefKey, "");
    return playerName;
}

Now, on Unity C# side, your plugin will have code like this

    AndroidJavaObject AJO = null;

public void SetPreferenceString (string prefKey, string prefValue) {
    if(AJO == null)
        AJO = new AndroidJavaObject("com.yourcompany.productname.activity", new object[0]);

    AJO.Call("setPreferenceString", new object[] { prefKey, prefValue } );
}

public string GetPreferenceString (string prefKey) {
    if(AJO == null)
        AJO = new AndroidJavaObject("com.yourcompany.productname.activity", new object[0]);

    if(AJO == null)
        return string.Empty;
    return AJO.Call<string>("getPreferenceString", new object[] { prefKey } );
}

Usage in Unity

//Setting a player's name to be "John Doe"
void Start () {
    SetPreferenceString("playerName", "John Doe");
}

//Get the stored player's name
string GetPlayerName () {
    return GetPreferenceString("playerName");
}

This is by no means the best way of writing the plugin. It should, however give you a fair idea how to handle SharedPrefs.

Obviously, ensure that both of you are using the same preferences!