Adding a Toggle Button View
Android devices come fully equipped with various views that include buttons, check boxes, and text-entry fields so that you can quickly build your user interface. Some views are more complex, such as a date picker, a clock, and zoom controls.
Views also provide user interface events that inform you when a user has interacted with the particular view, such as tapping a button.
You need to add a button view to your application so that you can toggle silent mode on the phone.
To add a button to your layout, type the following code after
android:text=”Toggle Silent Mode”
You have now added a button to your view with an ID resource of
toggle Button. That’s how you reference the button in the Java code. (Chapter 5 tackles coding.)
The height and width are set to
wrap_content, which informs the Android layout system to place the view onscreen and occupy only as much usable space as it needs. The
property is the same as the
ImageView above it, centered horizontally.
The final property that has been introduced in this view is the
text property of the button, which sets the button’s text to
Toggle Silent Mode.
Your full code base should now look like this:
<?xml version=”1.0” encoding=”utf-8”?>