Only the last item added in ArrayList shows

Question

I am new to programming in general and am trying to add items to an ArrayList I created. I am then trying to display the ArrayList in an Android TextView to confirm the contents of the ArrayList. The simplified code is as follows:

 public TextView textView1;
 public ArrayList<String> namesArray = new ArrayList<>();
 public static final String DEFAULT= "N/A";

 public void contactsArray() {
    loadArrayButton = (Button) findViewById((R.id.loadArrayButton));
    loadArrayButton.setOnClickListener(new View.OnClickListener() {
        @Override

        public void onClick(View view) {
              SharedPreferences sharedPreferences = getSharedPreferences("MyData", Context.MODE_PRIVATE);
              int howMany = sharedPreferences.getAll().size();

              for (int i = 1; i < howMany; i ++) {
                  String name = sharedPreferences.getString("name" + i, DEFAULT);
                  namesArray.add(sharedPreferences.getString("name" + i, DEFAULT));
            }

I know the shared preferences are correctly saved because if I retrieve them individually they come up how I would expect them. When I display the contents of the ArrayList only the last item added to my ArrayList shows. The remaining code is as follows:

String listRepresentation = "";
for (String name : namesArray)
if ("".equals(listRepresentation))
    listRepresentation  = name; else
    listRepresentation  = ", " + name;
textView1.setText(listRepresentation );

Again the only thing that comes up is the last name added on in the for loop. Any help would be appreciated- Thanks!

Answer 1

In your loop to display the result you overwrite the string at every index.

Use += to fix the issue:

 String listRepresentation = "";
 for (String name : namesArray) {
     if ("".equals(listRepresentation)) {
          listRepresentation += name;
      } else {
          listRepresentation += ", " + name;
      }
 }
 textView1.setText(listRepresentation );

The operator += is equal to listRepresentation = listRepresentation + ...;

Answer 2

What you have missed that is:

You have just set the value listRepresentation but not added it in sequentially.

Solution:

You can use this code instead of your last portion code

String listRepresentation = "";
String showData = "";
for (String name : namesArray) {
    if ("".equals(listRepresentation)) {
        listRepresentation  = name;
    } else {
        listRepresentation  = ", " + name;
    }
showData = showData + listRepresentation;
}
textView1.setText(showData);

Answer 3

Please use StringBuilder instead of string (listRepresentation). The problem will be solved .

Answer 4

Do you know that if the sharedPreferences.getAll().size(); has for example 2 items your code put inside namesArray only 1 items? Try

for (int i = 1; i <= howMany; i ++) {
              String name = sharedPreferences.getString("name" + i, DEFAULT);
              namesArray.add(sharedPreferences.getString("name" + i, DEFAULT));
        }