1. Welcome!

2. Today we are going
to create a new
Android Application
from scratch.

3. Create a new
Android Project with
a name ToDoList
If you have problems, look through
previous tutorial.

4. Modify the main layout (activity_main.xml in /res/layout)
to include ListView, Button and EditText within a
LinearLayout.
<?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">
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="New To Do Item" />
<Button
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text = "Add" />
<ListView
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>

5. Its important to give Button, EditText and ListView
controls IDs so you can get reference to them in the
code.
<?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">
<EditText
android:id = "@+id/editText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="New To Do Item" />
<Button
android:id = "@+id/buttonAdd"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text = "Add" />
<ListView
android:id = "@+id/listView"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>

6. Now open your main Activity class (MainActivity.java at
/ src / com. … / ).
Default main activity prob looks like:
package com.example.todolist;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Takes layout from
resource folder we
have made recently.

7. We will work only with onCreate method. Firstly get
references to the ListView and EditText using
findViewById.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Inflate activity view
setContentView(R.layout.activity_main);
// Get reference to UI
ListView myListView = (ListView)findViewById(R.id.listView);
EditText myEditText = (EditText)findViewById(R.id.editText);
Button buttonAdd = (Button)findViewById(R.id.buttonAdd);
}

8. Now we need to create ArrayList of Strings to store
each to-do list item. (check out about array list if you are not sure)
And ArrayAdapter to store content in ListView.
(check out about array list if you are not sure)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Inflate activity view
setContentView(R.layout.activity_main);
// Get reference to UI
ListView myListView = (ListView)findViewById(R.id.listView);
EditText myEditText = (EditText)findViewById(R.id.editText);
Button buttonAdd = (Button)findViewById(R.id.buttonAdd);
// Create the array list of to-do items
ArrayList<String> todoItems = new ArrayList<String>();
// Create the array adapter to bind the array to the listview
ArrayAdapter<String> aa;
}

9. Next step to bind string array with array adapter and
with listView
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Inflate activity view
setContentView(R.layout.activity_main);
// Get reference to UI
ListView myListView = (ListView)findViewById(R.id.listView);
EditText myEditText = (EditText)findViewById(R.id.editText);
Button buttonAdd = (Button)findViewById(R.id.buttonAdd);
// Create the array list of to-do items
ArrayList<String> todoItems = new ArrayList<String>();
// Create the array adapter to bind the array to the listview
ArrayAdapter<String> aa;
aa = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
todoItems);
// Bind the array adapter to the listView
myListView.setAdapter(aa);
}
Defining array
adapter through
current object,
layout item and
array list.

10. The final step is to make to-do list functional.
Add onKeyListener to the EditText that listens for a
“D-pad center button” and add item to string array list.
Add final label for
variables used inside
OnKeyListner to make
sure they won't going
to change
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Inflate activity view
setContentView(R.layout.activity_main);
// Get reference to UI
ListView myListView = (ListView)findViewById(R.id.listView);
final EditText myEditText =
(EditText)findViewById(R.id.editText);
final Button buttonAdd = (Button)findViewById(R.id.buttonAdd);
// Create the array list of to-do items
final ArrayList<String> todoItems = new ArrayList<String>();
// Create the array adapter to bind the array to the listview
final ArrayAdapter<String> aa;
aa = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
todoItems);
// Bind the array adapter to the listView
myListView.setAdapter(aa);
buttonAdd.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
todoItems.add(0, myEditText.getText().toString());
aa.notifyDataSetChanged();
myEditText.setText("");
}
});
}

11. Run your application.
You should get something
like:

12. If you have problems check code on github:
(check out, if you are not sure about Github)
Or text me if you found any mistakes or you
want to add something to presentation: