MainActivity.java

package com.travis.q4dynamiclistview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private ArrayList<String> nameList;
    private ArrayAdapter<String> adapter;

    private TextView textView;
    private ListView listView;
    private EditText editText;
    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        textView = (TextView) findViewById(R.id.sign_text);
        editText = (EditText) findViewById(R.id.input_place);
        button = (Button) findViewById(R.id.update_button);
        button.setOnClickListener(this);

        listView = (ListView) findViewById(R.id.people_list);
        nameList = new ArrayList<>();
        adapter = new ArrayAdapter<>(this, android.R.layout.simple_expandable_list_item_1, nameList);
        listView.setAdapter(adapter);
    }

    @Override
    public void onClick(View v) {
        String name = editText.getText().toString();
        if (name == "") return;

        String text = name + " is learning Android development!";
        textView.setText(text);
        editText.setText(null);

        //adapter.add(name);
        nameList.add(name);
        adapter.notifyDataSetChanged();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}