Beginning Android

BASIC VIEWS

In the previous section, you learned about the various layouts that you can use to position your views in an activity. You also learned about the techniques you can use to adapt to different screen resolutions and sizes. In this section, you will take a look at the various views that you can use to design the user interface for your applications.

In particular, you will explore some of the basic views that you can use to design the UI of your Android applications:

• TextView
• EditText
• Button
• ImageButton
• CheckBox
• ToggleButton
• RadioButton
• RadioGroup

These basic views enable you to display text information, as well as perform some basic selection. The following sections explore all these views in more detail.

TextView View

When you create a new Android project, Eclipse always creates the main.xml file (located in the res/layout folder), which contains a <TextView> element:

<?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"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/hello"
    />
</LinearLayout>

The TextView view is used to display text to the user. This is the most basic view and one that you will frequently use when you develop Android applications. If you need to allow users to edit the text displayed, you should use the subclass of TextView, EditText ...