To dynammically add new elements into listview we need a Edittext(etAddItem) to input the item/element, a Button(btnAdd) for adding item to the list, and a listview which shows elements in a vertical scrolling manner.

        etAddItem = (EditText)findViewById(R.id.etAddItem);
        btnAdd = (Button)findViewById(R.id.btnAdd);
        listView = (ListView)findViewById(R.id.lvList);

btnAdd(Button) onClickListner, when user clicks on add button element/item is added to the arraylist.

 btnAdd.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        arrayList.add(etAddItem.getText().toString());
        adapter.notifyDataSetChanged();
        etAddItem.setText(null);
    }
});

finally, adapter works as a communication channel between Listview and ArrayList.

arrayList = new ArrayList();
adapter = new ArrayAdapter(getApplicationContext(), android.R.layout.simple_spinner_item, arrayList);

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