How to set countdown in android

First, you need to enter a second in the input box, such as 12, and then get the value in the input box and display it in a TextView; Click the "Start Countdown" button. Every second, the number of seconds decreases by 1, and then it is displayed in TextView; Click the Stop Countdown button to stop the timer. When you click the Start Countdown button again, the timer will continue to run.