Saving data upon closing app and retrieving that data

Question

I know, there are plenty of questions in regards to saving/retrieving data on here. I was doing find looking things up on my own and really thought I could manage to find m

Answer 1

Serialize an object and pass it around which is more dependable than shared preferences (had lots of trouble with consistency with shared preferences):

public class SharedVariables {

    public static  void writeObject(
            final Context context, String key, S serializableObject) {

        ObjectOutputStream objectOut = null;
        try {
            FileOutputStream fileOut = context.getApplicationContext().openFileOutput(key, Activity.MODE_PRIVATE);
            objectOut = new ObjectOutputStream(fileOut);
            objectOut.writeObject(serializableObject);
            fileOut.getFD().sync();
        } catch (IOException e) {
            Log.e("SharedVariable", e.getMessage(), e);
        } finally {
            if (objectOut != null) {
                try {
                    objectOut.close();
                } catch (IOException e) {
                    Log.e("SharedVariable", e.getMessage(), e);
                }
            }
        }
    }

Then use a class to use:

public class Timestamps implements Serializable {

private float timestampServer;

public float getTimestampServer() {
    return timestampServer;
}

public void setTimestampServer(float timestampServer) {
    this.timestampServer = timestampServer;
}

}

Then wherever you want to write to the variable use:

SharedVariables.writeObject(getApplicationContext(), "Timestamps", timestampsData);