How do I use List<String> for ArrayAdapter values (Java, Android)

Question

I'm trying to update listView items when application is running. I can make it work by using a String[] instead of List but my goal is make it work with List so I can add more items to listView while application is running.

private List<String> items;

I have made a List to MainActivity class.

ListView listView = (ListView)findViewById(R.id.listView);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, R.layout.support_simple_spinner_dropdown_item, items);
listView.setAdapter(adapter);

This doesn't work. I tried to hassle with items.ToArray(), but didn't found a solution. Tried Googling, but all results from Google redirects only to tutorials that shows how to make listView and every of tutorials were based on String[] array.

Application works fine if I use following:

private String[] items = {"Banana", "Lime"};

I want manage items real time when user adds them to list by using: "adapter.notifyDataSetChanged();"

I'm beginner on Java and especially about Android Developing so help is appreciated.

Assuming you initialized the arraylist, then your code should work. adapter.add("hello") would update the list without the need for notifyDataSetChanged — OneCricketeer
– OneCricketeer, Commented Jul 31, 2016 at 19:32

Community · Accepted Answer · 2017-05-23 11:51:32Z

1

You have two approach to do this:

Convert your List to Array (you can find a good example here).
Create your own Adapter and use List ( another good example here).

First Approach:

List<String> stockList = new ArrayList<String>();
stockList.add("stock1");
stockList.add("stock2");

String[] stockArr = new String[stockList.size()];
stockArr = stockList.toArray(stockArr);

for(String s : stockArr)
    System.out.println(s);

Second Approach:

public class CustomAdapter extends BaseAdapter{   

    String [] result;
    Context context;
    int [] imageId;
    private static LayoutInflater inflater=null;

    public CustomAdapter(MainActivity mainActivity, String[] prgmNameList, int[] prgmImages) {
        // TODO Auto-generated constructor stub
        result=prgmNameList;
        context=mainActivity;
        imageId=prgmImages;
         inflater = ( LayoutInflater )context.
                 getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }
}

edited May 23, 2017 at 11:51

CommunityBot

11 silver badge

answered Jul 31, 2016 at 19:16

Amir

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5 Comments

Weird E. Over a year ago

Damn. Didn't found such information through Google. I guess I am at so beginning so I didn't knew good enough keywords. Thanks Amir.

Amir Over a year ago

@WeirdE. If answers gives you enough information you can accept them.

Weird E. Over a year ago

Sure. Waiting for it. Site requires 5 minutes before I can accept it.

OneCricketeer Over a year ago

You could extend ArrayAdapter instead of BaseAdapter. Otherwise, you left out that you need to implement getCount and such

Amir Over a year ago

@cricket_007 yes you're right. I just paste some piece of code which is necessary ¯_(ツ)_/¯

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