Populate ListView with Dynamic Array

Question

I have a EditText box so a user can input names and then click the Add button and the name saves to the array playerList and clears the box so another name can be added.

I also have a ListView on the same Activity which will then be populated by the names in the Array playerList. The problem is that the ListView dosen't seem to be populated.

So I tried with a defualt set String teststring which you can see below and that populates the ListView fine. My question is how come it isn't working with the Array playerList maybe its not saving to the Array correctly?

Update just need adapter.notifyDataSetChanged(); adding to refresh the ListView Credit to @Lalit Poptani and @Jave

ArrayList<String> playerList = new ArrayList<String>();
ListView listview;
protected String[] teststring = {"Name 1", "Name 2"};

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.addremove);
ListAdapter adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, teststring);
ListView employeeList = (ListView) findViewById(R.id.namelistview);
employeeList.setAdapter(adapter);


Button confirm = (Button) findViewById(R.id.add);
confirm.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
EditText playername = (EditText) findViewById(R.id.userinput);
String name = playername.getText().toString();
playerList.add(name);
playername.setText("");

}});

have you tried printing the array values i mean playerlist values..???? Is array populating fine..???? if yes then you must call notifyDataSetChnaged() whenever is adapter updated. — Usama Sarwar
– Usama Sarwar, Commented Jan 12, 2012 at 10:34

Lalit Poptani · Accepted Answer · 2012-01-12 10:48:04Z

3

To refresh the ListView after you add new data to it you have to call adapter.notifyDataSetChanged(). This is refresh your ListView will new data.

But in your case you are populating your ListView with String[] so it won't work dynamically you will have to give the size of the String[]. So, I will suggest you to populate your ListView with ArrayList itself for adding the content dynamically.

ListAdapter adapter = new ArrayAdapter<String>
                       (this, android.R.layout.simple_list_item_1,playerList);

edited Jan 12, 2012 at 10:48

answered Jan 12, 2012 at 10:31

Lalit Poptani

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8 Comments

Jave Over a year ago

Heh, answering 4 secs before me :p

Matt Over a year ago

@Lalit Where abouts should that be called?

Lalit Poptani Over a year ago

Matt in your button when you add data in your arrayList just after that call adapter.notifyDataSetChanged()

Matt Over a year ago

@LalitPoptani Ahh ok so then I would have to convert my ListAdapter to final ListAdapter adapter

Lalit Poptani Over a year ago

You can but I will say to declare ListAdapter adapter; globally above onCreate.

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Jave · Accepted Answer · 2012-01-12 10:31:53Z

2

You should call adapter.notifyDataSetChanged() after adding new items to make it update with the new data.

Notifies the attached observers that the underlying data has been changed and any View reflecting the data set should refresh itself.

answered Jan 12, 2012 at 10:31

Jave

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6 Comments

Matt Over a year ago

Where abouts should it be called?

Jave Over a year ago

Just after you have updated the list. It basically tells it that it has new items in it.

Matt Over a year ago

so it would be after playerList.add(name);

Matt Over a year ago

Cool, but getting the error The method notifyDataSetChanged() is undefined for the type ListAdapter :/

Jave Over a year ago

Ah, you can(should) define it as an ArrayAdapter instead of a ListAdapter: ArrayAdapter<String> adapter = new ArrayAdapter(args);

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