android.os.CountDownTimer is an abstract class which provide count down timer function. You must create a sub class of it to use. This example will show you how to use android.os.CountDownTimer to implement verification code retrieval function.
android.widget.Chronometer is an android provides timer component.It is also extends android.widget.TextView. So you can use a lot of TextView’s xml attributes and methods. But this article will show you examples about how to use Chronometer self owned attributes and methods.
FrameLayout is used to allocate a part of screen to a single View component to display. It is similar to CardLayout in Swing programming. A FrameLayout component can include multiple view components. The position of each child view component is decided by it’s android:layout_gravity attribute value. This article will show you an example about how to …