The Widget exploration mini app
We just talked about seven widgets. The EditText, ImageView, RadioButton (and RadioGroup), Switch, CheckBox, WebView, and TextClock widgets. Let's make a mini app and do something real with each of them. We will also use Button as well.
Setting up the widget exploration project and UI
First, we will set up a new project and prepare the UI layout. These quick steps will get all the widgets on the screen and set the id properties, ready to grab a reference to them. It will help us to take a look at the target app (as shown in this next figure), which is up and running, before we get started:

Here is how this app will demonstrate these new widgets:
- The radio buttons will allow the user to change the time displayed on the clock with a choice of three time zones
- The button on the left side, when clicked, will change its text to whatever is currently in the
EditTextwidget - The three checkboxes will add and remove visual effects from the Android robot image
Switch...