How do you dynamically add elements to a ListView on Android?

Question

Can anyone explain or suggest a tutorial to dynamically create a ListView in android?

Here are my requirements:

• I should be able to dynamically add new elements by pressing a button.
• Should be simple enough to understand (possibly without any performance improvements or convertView, for instance)

I know there are quite a few questions on this topic, but I couldn't find any that answer my question.

Hillie

The currently highest-voted answer from Shardul is considered high quality and users have expressed they feel it should be accepted. Can you consider accepting it? – Yellowstone

Answer 1

Create an XML layout first in your project's res/layout/main.xml folder:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
    <Button
        android:id="@+id/addBtn"
        android:text="Add New Item"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:onClick="addItems"/>
    <ListView
        android:id="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:drawSelectorOnTop="false"
    />
</LinearLayout>

This is a simple layout with a button on the top and a list view on the bottom. Note that the ListView has the id @android:id/list which defines the default ListView a ListActivity can use.

public class ListViewDemo extends ListActivity {
    //LIST OF ARRAY STRINGS WHICH WILL SERVE AS LIST ITEMS
    ArrayList<String> listItems=new ArrayList<String>();

    //DEFINING A STRING ADAPTER WHICH WILL HANDLE THE DATA OF THE LISTVIEW
    ArrayAdapter<String> adapter;

    //RECORDING HOW MANY TIMES THE BUTTON HAS BEEN CLICKED
    int clickCounter=0;

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);
        adapter=new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1,
            listItems);
        setListAdapter(adapter);
    }

    //METHOD WHICH WILL HANDLE DYNAMIC INSERTION
    public void addItems(View v) {
        listItems.add("Clicked : "+clickCounter++);
        adapter.notifyDataSetChanged();
    }
}

android.R.layout.simple_list_item_1 is the default list item layout supplied by Android, and you can use this stock layout for non-complex things.

listItems is a List which holds the data shown in the ListView. All the insertion and removal should be done on listItems; the changes in listItems should be reflected in the view. That's handled by ArrayAdapter<String> adapter, which should be notified using:

adapter.notifyDataSetChanged();

An Adapter is instantiated with 3 parameters: the context, which could be your activity/listactivity; the layout of your individual list item; and lastly, the list, which is the actual data to be displayed in the list.

Geomancy

I don't understand how the ListView attaches itself to our activity here. – Magnificence

@Magnificence Because it's a ListActivity and not an Activity which has a layout with a ListView. You don't need to find the id's view. As you can read on the Reference: ListActivity is an activity that includes a ListView as its only layout element by default. [...] (it) hosts a ListView object. So, by default the methods (as setAdapter, etc) are "inside" the Class. – Nougat

Did you mean setAdapter(Adapter) not setListAdapter? – Antalkali

If element in ArrayList is more complicated such as loading from Internet and each item contains image video and something like that,would this approach face performance hit? – Abnormity

I wonder if there's a difference between Android Studio 2.3 and whatever version Shardul had at the time? I try following the directions given, and am repeatedly told via popup "Cannot resolve symbol '@android:id/listfview' " (as well as a similar compile error) I've tried switching from ConstraintLayout to LinearLayout, but it made no difference – Wisp

How could I implement this in a fragment? – Sire

Answer 2

instead of

listItems.add("New Item");
adapter.notifyDataSetChanged();

you can directly call

adapter.add("New Item");

Morrissette

@gumuruh the adapter itself is mutable so we can directly add or remove objects which will call the notifyDatasetChanged() and getView() of listView automatically. This reduce the extra line of code. – Morrissette

so by adding into the adapter automatically call notifyDatasetChanged() ? Oh, I see. Thanks @venkat530. But what about the list itself? I mean if let say firstly he created an arraylist that used as a data container for the adapter. And now you just add an item directly to the adapter instead to the arraylist. Would the arraylist data is updated / untouched? – Dou

@Dou the second is the best practice because is synchronized. – Bakerman

@Dou from cursory experimentation and the ArrayAdapter source code [github.com/android/platform_frameworks_base/blob/master/core/…, it looks like the underlying data set will also be modified. – Barrybarrymore

I got Shardul's answer working, then broke it and couldn't figure out how to repair it. On a whim, I thought I would try this out, and voila, it works again! Thank you very much! Though, I have no idea how or why it fixed it. Any idea? – Wisp

it's not supported any more – Drawn

Answer 3

First, you have to add a ListView, an EditText and a button into your activity_main.xml.

Now, in your ActivityMain:

private EditText editTxt;
private Button btn;
private ListView list;
private ArrayAdapter<String> adapter;
private ArrayList<String> arrayList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    editTxt = (EditText) findViewById(R.id.editText);
    btn = (Button) findViewById(R.id.button);
    list = (ListView) findViewById(R.id.listView);
    arrayList = new ArrayList<String>();

    // Adapter: You need three parameters 'the context, id of the layout (it will be where the data is shown),
    // and the array that contains the data
    adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_spinner_item, arrayList);

    // Here, you set the data in your ListView
    list.setAdapter(adapter);

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            // this line adds the data of your EditText and puts in your array
            arrayList.add(editTxt.getText().toString());
            // next thing you have to do is check if your adapter has changed
            adapter.notifyDataSetChanged();
        }
    });
}

This works for me, I hope I helped you

Glut

Very good explanation and thanks especially for explaining the adapter item -- which seems to magically appear in everyone else's examples. :) – Thylacine

This is the best example i found for this :) – Winy

This answer satisfied what the person asked for. Simple and clean without complicated improvements. The top answer actually introduces ListActivity, which only grand masters know about. My only problem now is how to I add drawables and stuff to views in the list. Seems to me I am only adding strings. – Decencies

An optimization might be to create unnamed List object in Adapter than to create a 16 bit pointer to an list object. Which is not needed after creating the adapter because adapter has an add method. – Decencies

Answer 4

If you want to have the ListView in an AppCompatActivity instead of ListActivity, you can do the following (Modifying @Shardul's answer):

public class ListViewDemoActivity extends AppCompatActivity {
    //LIST OF ARRAY STRINGS WHICH WILL SERVE AS LIST ITEMS
    ArrayList<String> listItems=new ArrayList<String>();

    //DEFINING A STRING ADAPTER WHICH WILL HANDLE THE DATA OF THE LISTVIEW
    ArrayAdapter<String> adapter;

    //RECORDING HOW MANY TIMES THE BUTTON HAS BEEN CLICKED
    int clickCounter=0;
    private ListView mListView;

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.activity_list_view_demo);

        if (mListView == null) {
            mListView = (ListView) findViewById(R.id.listDemo);
        }

        adapter=new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                listItems);
        setListAdapter(adapter);
    }

    //METHOD WHICH WILL HANDLE DYNAMIC INSERTION
    public void addItems(View v) {
        listItems.add("Clicked : "+clickCounter++);
        adapter.notifyDataSetChanged();
    }

    protected ListView getListView() {
        if (mListView == null) {
            mListView = (ListView) findViewById(R.id.listDemo);
        }
        return mListView;
    }

    protected void setListAdapter(ListAdapter adapter) {
        getListView().setAdapter(adapter);
    }

    protected ListAdapter getListAdapter() {
        ListAdapter adapter = getListView().getAdapter();
        if (adapter instanceof HeaderViewListAdapter) {
            return ((HeaderViewListAdapter)adapter).getWrappedAdapter();
        } else {
            return adapter;
        }
    }
}

And in you layout instead of using android:id="@android:id/list" you can use android:id="@+id/listDemo"

So now you can have a ListView inside a normal AppCompatActivity.

Piggy

Answer 5

Code for MainActivity.java file.

public class MainActivity extends Activity {

    ListView listview;
    Button Addbutton;
    EditText GetValue;
    String[] ListElements = new String[] {
        "Android",
        "PHP"
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        listview = (ListView) findViewById(R.id.listView1);
        Addbutton = (Button) findViewById(R.id.button1);
        GetValue = (EditText) findViewById(R.id.editText1);

        final List < String > ListElementsArrayList = new ArrayList < String >
            (Arrays.asList(ListElements));


        final ArrayAdapter < String > adapter = new ArrayAdapter < String >
            (MainActivity.this, android.R.layout.simple_list_item_1,
                ListElementsArrayList);

        listview.setAdapter(adapter);

        Addbutton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {

                ListElementsArrayList.add(GetValue.getText().toString());
                adapter.notifyDataSetChanged();
            }
        });
    }
}

Code for activity_main.xml layout file.

<RelativeLayout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:paddingBottom="@dimen/activity_vertical_margin"
  android:paddingLeft="@dimen/activity_horizontal_margin"
  android:paddingRight="@dimen/activity_horizontal_margin"
  android:paddingTop="@dimen/activity_vertical_margin"
  tools:context="com.listviewaddelementsdynamically_android_examples
    .com.MainActivity" >

  <Button
    android:id="@+id/button1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/editText1"
    android:layout_centerHorizontal="true"
    android:text="ADD Values to listview" />

  <EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="26dp"
    android:ems="10"
    android:hint="Add elements listView" />

  <ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/button1"
    android:layout_centerHorizontal="true" >
  </ListView>

</RelativeLayout>

ScreenShot

Trodden

Answer 6

The short answer: when you create a ListView you pass it a reference to the data. Now, whenever this data will be altered, it will affect the list view and thus add the item to it, after you'll call adapter.notifyDataSetChanged();.

If you're using a RecyclerView, update only the last element (if you've added it at the end of the list of objs) to save memory with: mAdapter.notifyItemInserted(mItems.size() - 1);

Glace

Answer 7

        This is the simple answer how to add datas dynamically in listview android kotlin


class MainActivity : AppCompatActivity(){
        
            var listItems = arrayListOf<String>()
            val array = arrayOf("a","b","c","d","e")
            var listView: ListView? = null
    
            private lateinit var adapter: listViewAdapter
        
            override fun onCreate(savedInstanceState: Bundle?) {
                super.onCreate(savedInstanceState)
                setContentView(R.layout.scrollview_layout)
        
                listItems.add("a")
                listItems.add("b")
                listItems.add("c")
                listItems.add("d")
                listItems.add("e")
        
                //if you want to add array items to a list you can try this for each loop
                for(items in array)
                    listItems.add(items)
                
                //check the result in console
                Log.e("TAG","listItems array: $listItems")
    
            adapter = ListViewAdapter()
            adapter.updateList(listItems)
            adapter.notifyDataSetChanged()
        
            }
        }


//Here is the adapter class
    class ListviewAdapter : BaseAdapter(){
    
    private var itemsList = arrayListOf<String>()
    
    override fun getView(position: Int, container: View?, parent: ViewGroup?): View {
            var view  = container
            val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
            if (view == null)
                view = inflater.inflate(R.layout.list_pc_summary, parent, false)
    
    return view
    }
    
    override fun getItem(position: Int): Any  = itemsList[position]
    
    override fun getItemId(position: Int): Long = position.toLong()
    
    override fun getCount(): Int = itemsList.size
    
    fun updateList(listItems: ArrayList<String>()){
        this.itemsList = listItems
        notifyDatSetChanged
    
    }
   
        }
       
    //Here I just explained two ways, we can do this many ways.

Stopper

Where's the part that you add it to the ListView? – Crenelation

@OnieManiego here i added the items to listview in two ways, you can see that above 1. listItems.add("a") listItems.add("b") listItems.add("c") listItems.add("d") listItems.add("e") this is the first way i added 2. for(items in array) listItems.add(items) second way i added all items from array – Stopper

@OnieManiego i hope u understand, if that helpful to you pls upvote – Stopper

to be honest i only see you adding them to an array of string (listItems), but there's no correlation between the array and the listView... – Aiden

sorry, i didn't get your question, just say what u want exactly – Stopper

@Federico Capece if u want the listItems add to listview u need a adapter class and pass the listview into the adapter class. if you want more details about how to set listview plaese reffer google or msg me, i will share the code – Stopper

@sirajudheentk i know, and that's the point of my comment: your answer doesn't give to OP a way to add items to a listview since you didn't put an adapter. – Aiden

@Federico Capece honestly i agree with that, i will update my answer ASAP, thank you for your suggestion – Stopper