Odd output from file

Question

I have an issue with the input I am getting from reading a file.

The file is made in another activity and is very simple:

ArrayList stuff = new ArrayList();
stuff.add("1,2,3");

try{
String saveFile = "saveGamesTest1.csv";
FileOutputStream saveGames = openFileOutput(saveFile, getApplicationContext().MODE_APPEND);    

ObjectOutputStream save = new ObjectOutputStream(saveGames);

save.writeObject(stuff);    
save.close(); }

In the other activity it's being read via

try {
            FileInputStream fileIn=openFileInput("saveGamesTest1.csv");
            InputStreamReader InputRead = new InputStreamReader(fileIn);

            Scanner s = new Scanner(InputRead).useDelimiter(",");
            System.out.println(s.next());
            System.out.println(s.next());
            System.out.println(s.next());

        }

I was expecting (and hoping) to get a result back like

1
2
3

However, the result I'm getting is this:

/storage/emulated/0/Android/data/ys.test/files/saveGamesTest1.csv����sr��java.util.ArrayListx����a���I��sizexp������w������t��1
2
3x

What am I doing wrong?
.

EDIT
I tried Serializable as suggested below, like follow:

public class Save implements java.io.Serializable {
        public String name;
        public String address;
        public transient int SSN;
        public int number;

    }


    public void save(){

        Save e = new Save();
        e.name = "Reyan Ali";
        e.address = "Phokka Kuan, Ambehta Peer";
        e.SSN = 11122333;
        e.number = 101;

        try {
            String saveFile = "save.ser";
            FileOutputStream saveGames = openFileOutput(saveFile, getApplicationContext().MODE_APPEND);
            ObjectOutputStream out = new ObjectOutputStream(saveGames);
            out.writeObject(e);
            out.close();
            saveGames.close();
            System.out.printf("Serialized data is saved in save.csv");
        }
        catch(IOException i) {
            i.printStackTrace();
            out.println("Save exception gepakt");
        }
    }  

However, out.writeObject(e); gives an error saying that this isn't Serializable

Answer 1

You are not storing object as csv but as serialize java object you have to read as an object not as a csv file

take a look here https://www.tutorialspoint.com/java/java_serialization.htm at Serializing an Object part

You have to use

FileInputStream in = null;
ObjectInputStream ois = null;
ArrayList stuff2 = null;
try {
    in = openFileInput("saveGamesTest1.csv");
    ois = new ObjectInputStream(in);
    stuff2 = (ArrayList) ois.readObject();
} catch(IOException e) {...}
catch(ClassNotFoundException c) {...}
finally {
    if (ois != null) {
        ois.close();
    }
    if (in != null) {
        in.close();
    }
}

If you want a csv file you have to build it for instance by iterate over your array and write one by one the value in your file and adding the separator or follow this How to serialize object to CSV file?

EDIT : An elegant way in Java 7 to serialize an object (here a list like in your example) and deserialize :

public class Main {

public static void main(String[] args) {
    List<Integer> lists = new ArrayList<>();
    List<Integer> readList = null;
    String filename = "save.dat";
    lists.add(1);
    lists.add(2);
    lists.add(3);

    //serialize
    try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(filename))) {
        oos.writeObject(lists);
    } catch (IOException e) {
        e.printStackTrace();
    }
    //don't need to close because ObjectOutputStream implement AutoCloseable interface

    //deserialize
    try (ObjectInputStream oos = new ObjectInputStream(new FileInputStream(filename))) {
        readList = (List<Integer>) oos.readObject();
    } catch (IOException | ClassNotFoundException e) {
        e.printStackTrace();
    }
    //don't need to close because ObjectInputStream implement AutoCloseable interface


    //test
    if(!lists.equals(readList)) {
        System.err.println("error list saved is not the same as the one read");
    }
}

}