android.os.CountDownTimer is an abstract class that provides a 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 a 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 …