Question

我想在我的JavaFX应用程序中实现一个计数器。只需通过Button：

控制行为

当用户先点击按钮时，倒计时开始倒计时10,9,8，...，0
当用户在倒计时期间点击按钮时，倒计时应取消
2.用户应该能够从10开始再次运行倒计时

在倒计时期间，处理了一些繁重的数学计算（在我的应用程序音频分析中）。

如果我以正确的方式做到这一点，你能看看我的源代码吗？特别应该在Platform.runLater或CountdownController上执行CountdownView内容，我可以使用简单的Java Thread，还是应该使用JavaFX Service / Task课程？欢迎任何建议。

该申请分为3个部分：

CountdownTest：创建舞台并启动JavaFX）
CountdownView：singleton，包含一个简单的Button，将按钮事件传递给CountdownController
CountdownController：单身，开始新的Thread。在执行倒计时的Thread内，CountdownView为updatet以显示新的倒计时状态，并处理了一些数学内容。

CountdownTest.java

package org.example;

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class CountdownTest extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {
        final Group root = new Group();
        final Scene scene = new Scene(root);
        root.getChildren().setAll(CountdownView.getInstance());
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    @Override
    public void stop() throws Exception {
        super.stop();
        CountdownController.getInstance().stop();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

CountdownView.java

package org.example;

import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.control.Button;
import javafx.scene.control.Tooltip;
import javafx.scene.input.MouseEvent;

public final class CountdownView extends Group {
    private static final CountdownView instance = new CountdownView();

    private Button start;

    private CountdownView() {
        start = new Button("Start");
        start.setTooltip(new Tooltip("click to start countdown"));
        start.setOnMouseClicked(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                CountdownController.getInstance().onStartClick();
            }
        });

        this.getChildren().setAll(start);
    }

    public void startCountdown() {
        System.out.println("startCountdown");
        start.setTooltip(new Tooltip("click to stop countdown"));
    }

    public void setCountdown(final int countdown) {
        System.out.println("setCountdown " + countdown);
        start.setText(String.valueOf(countdown));
    }

    public void reset() {
        System.out.println("reset");
        start.setText("Start");
        start.setTooltip(new Tooltip("click to start countdown"));
    }

    public static CountdownView getInstance() {
        return instance;
    }
}

CountdownController.java

package org.example;

import javafx.application.Platform;

public final class CountdownController {
    private static final CountdownController instance = new CountdownController();

    private Thread countdownThread;
    private volatile boolean running = false;

    public void onStartClick() {
        if (!running) {
            countdownThread = new Thread(new Runnable() {
                @Override
                public void run() {
                    running = true;
                    int countdown = 10;
                    Platform.runLater(new Runnable() {
                        @Override
                        public void run() {
                            CountdownView.getInstance().startCountdown();
                            CountdownView.getInstance().setCountdown(10);
                        }
                    });
                    final long start = System.currentTimeMillis();
                    int lastCountdown = countdown;
                    while (!Thread.interrupted() && countdown > 0) {
                        countdown = (int) (10 - (System.currentTimeMillis() - start) / 1000);
                        if (countdown != lastCountdown) {
                            lastCountdown = countdown;
                            final int currentCountdown = countdown;
                            Platform.runLater(new Runnable() {
                                @Override
                                public void run() {
                                    CountdownView.getInstance().setCountdown(
                                            currentCountdown);
                                }
                            });
                        }

                        // Do some heavy computing stuff
                        for (int i = 0; i < 10000000; i++) {
                            Math.sin(Math.random());
                        }
                    }
                    running = false;
                    Platform.runLater(new Runnable() {
                        @Override
                        public void run() {
                            CountdownView.getInstance().reset();
                        }
                    });
                }
            });
            countdownThread.start();
        } else {
            countdownThread.interrupt();
        }
    }

    public void stop() {
        if (countdownThread != null) {
            System.out.println("stop");
            countdownThread.interrupt();
        }
    }

    public static CountdownController getInstance() {
        return instance;
    }
}

Answer 1

不要过度出汗。任务和服务类只是在执行程序上构建的一些实用程序，如果你不需要他们提供的东西，那么它只是额外的工作。

我认为你使用控制器决定应该运行哪些线程是正确的，你的视图足以在组件和控制器之间进行路由消息。

控制另一个线程的倒计时

1 个答案: