java程序: 倒计时的小程序 （GridPane, Timer, Calendar, SimpleDateFormat ...）

倒计时程序

涉及到的东西：

javafx简单的界面，布局，按钮，文本框，事件响应

java.util.Timer，用于定时

SimpleDateFormat用于在String和Date之间转换。

java.util.Calendar，表示时间，用于定时计算。

贴代码

 package countDownTimer;

 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.Timer;
 import java.util.TimerTask;

 import javafx.application.Application;
 import javafx.event.ActionEvent;
 import javafx.event.EventHandler;
 import javafx.geometry.HPos;
 import javafx.geometry.Insets;
 import javafx.geometry.Pos;
 import javafx.scene.Scene;
 import javafx.scene.control.Button;
 import javafx.scene.control.TextField;
 import javafx.scene.layout.GridPane;
 import javafx.scene.layout.Priority;
 import javafx.scene.text.Font;
 import javafx.scene.text.FontWeight;
 import javafx.scene.text.Text;
 import javafx.stage.Stage;
 import javafx.stage.WindowEvent;

 public class App extends Application {

     Timer timer = new Timer();
     Button btnStart = new Button("Start");
     Button btnPause = new Button("Pause");
     Button btnSet = new Button("Set");
     Text textTimeleft = new Text("HH:MM:SS");
     TextField textSet = new TextField("HH:MM");
     Calendar timenow =  Calendar.getInstance();
     Calendar timeZero =  Calendar.getInstance();
     boolean bPause = false;

     TimerTask timerTask = new TimerTask() {

         @Override
         public void run() {

             if (bPause) {
                 if(timenow.compareTo(timeZero)>0) {
                     timenow.set(Calendar.SECOND, timenow.get(Calendar.SECOND)-1);
                     if ((timenow.getTimeInMillis() - timeZero.getTimeInMillis()) <= 10000) {
                         flashText();
                     }
                 }else {
                     bPause = false;
                 }
                 //display
                 SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
                 String dateString = formatter.format(timenow.getTime());
                 textTimeleft.setText(dateString);
             }
         }
     };

     boolean bToggle = false;
     private void flashText() {

         bToggle = !bToggle;
         if(bToggle) {
             textTimeleft.setFont(Font.font("Tahoma", FontWeight.BOLD, 64));
         }else {
             textTimeleft.setFont(Font.font("Tahoma", FontWeight.NORMAL, 64));
         }
     }
     public static void main(String[] args) {
         launch(args);
     }

     @Override
     public void start(Stage primaryStage) throws Exception {

         timer.scheduleAtFixedRate(timerTask, 0, 1000);
         try {
             SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
             Date dateZero = sdf.parse("00:00");
             Date dataSet = sdf.parse("00:10");
             timenow.setTime(dataSet);
             timeZero.setTime(dateZero);
             textTimeleft.setText("00:10:00");
         } catch (ParseException e) {
         }

         btnStart.setOnAction(new EventHandler<ActionEvent>() {
             @Override
             public void handle(ActionEvent event) {
                 bPause = true;
             }
         });

         btnPause.setOnAction(new EventHandler<ActionEvent>() {
             @Override
             public void handle(ActionEvent event) {
                 bPause = false;
             }
         });

         btnSet.setOnAction(new EventHandler<ActionEvent>() {
             @Override
             public void handle(ActionEvent event) {
                 SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
                 try {
                     timenow.setTime(sdf.parse(textSet.getText()));
                     sdf = new SimpleDateFormat("HH:mm:ss");
                     String dateString = sdf.format(timenow.getTime());
                     textTimeleft.setText(dateString);
                 } catch (ParseException e) {
                 }
             }
         });

         GridPane grid = new GridPane();
         grid.setAlignment(Pos.CENTER);
         grid.setPadding(new Insets(25, 25, 25, 25));

         grid.add(btnStart, 0, 0);
         grid.add(btnPause, 2, 0);
         grid.add(btnSet, 2, 2);
         textTimeleft.setFont(Font.font("Tahoma", FontWeight.NORMAL, 64));
         grid.add(textTimeleft, 0, 1, 2, 1);
         GridPane.setHalignment(textTimeleft, HPos.CENTER);
         GridPane.setColumnSpan(textTimeleft, GridPane.REMAINING);
         GridPane.setHgrow(textTimeleft, Priority.ALWAYS);
         grid.add(textSet, 0, 2);

         Scene scene = new Scene(grid);
         primaryStage.setScene(scene);

         primaryStage.setTitle("倒计时");
         primaryStage.show();
         primaryStage.setOnCloseRequest(new EventHandler<WindowEvent>() {
             @Override
             public void handle(WindowEvent event) {
                 timer.cancel();
             }
         });
     }
 }