Steps to create a basic Android Activity with UI

This is a summary of basic things you need to cover when creating an Activity in relation to the UI

1. Create a new class file
2. Declare that extends Activity
3. Register it at AndroidManifest.xml
4. Create a new XML file of type Layout
5. For the Layout set some of this properties: Orientation, Background
6. Create a TextView and set some of this properties: Text, Text size, Text style, gravity, Layout width
7. Create an EditText and set some of this properties: Id, Hint, Layout gravity, Layout width
8. Create a Button and set some of this properties: Id, Layout gravity, Text, On click
9. Override method onCreate and inflate the Layout
10. Add the method to receive the Click event and do something

AndroidManifest.xml (partial)

<activity
  android:name=".uiBasics"
  android:label="@string/uiBasics">
</activity>

uibasics.java

package com.correa.android.tests.uibasics;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class uiBasics extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.uibasics);
  }
  public void onClickMyButton(View view) {
    EditText textMyEditText;
    textMyEditText =
      (EditText) findViewById(R.id.MyEditText);
    Toast.makeText(this, textMyEditText.getText(),
      Toast.LENGTH_LONG).show();
  }
}

uibasics.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  android:background="#AA0000FF">
  <TextView android:id="@+id/textView1"
    android:layout_height="wrap_content"
    android:textSize="20sp"
    android:layout_width="fill_parent"
    android:text="@string/textTextView1"
    android:textStyle="bold"
    android:gravity="center">
  </TextView>
  <EditText android:layout_height="wrap_content"
    android:hint="Type something here"
    android:layout_gravity="center"
    android:layout_width="250sp"
    android:id="@+id/MyEditText">
  </EditText>
  <Button android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:text="Press Me!"
    android:id="@+id/MyButton"
    android:onClick="onClickMyButton">
  </Button>
</LinearLayout>