Question

我在java中使用Webcam Capture API来访问我的网络摄像头。 Webcam Capture API是基于Swing构建的，我知道，但是我想将Webcam Swing类与我的JavaFX类结合起来。 JavaFX类在屏幕上显示一个矩形。我的目标是：运行我的JavaFX类，在屏幕上显示矩形。在某些时候（例如鼠标点击）我想启动网络摄像头。网络摄像头设置为查看屏幕，然后应该使用矩形的图像做某些事情。

JavaFX类：

public class JavaFXDisplay extends Application {

    @Override
    public void start(Stage primaryStage) {
        WebcamCapture wc = new WebcamCapture();

        StackPane root = new StackPane();

        Rectangle rectangle = new Rectangle();
        rectangle.setWidth(500);
        rectangle.setHeight(500);

        Scene scene = new Scene(root, 1000, 1000);
        root.getChildren().addAll(rectangle);

        primaryStage.setScene(scene);
        primaryStage.show();

        scene.addEventFilter(MouseEvent.MOUSE_PRESSED, new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent mouseEvent) {
                wc.doSomething();
            }
        });
   }

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

Swing课程：

public class WebcamCapture extends JFrame implements Runnable, ThreadFactory {

    private static final long serialVersionUID = 6441489157408381878L;

    private Executor executor = Executors.newSingleThreadExecutor(this);

    private Webcam webcam = null;
    private WebcamPanel panel = null;
    private JTextArea textarea = null;

    public WebcamCapture() {
        super();

        setLayout(new FlowLayout());
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        Dimension size = WebcamResolution.QVGA.getSize();

        webcam = Webcam.getWebcams().get(0);
        webcam.setViewSize(size);

        panel = new WebcamPanel(webcam);
        panel.setPreferredSize(size);

        textarea = new JTextArea();
        textarea.setEditable(false);
        textarea.setPreferredSize(size);

        add(panel);
        add(textarea);

        pack();
        setVisible(true);
    }

    public void doSomething() {
        executor.execute(this);
    }

    @Override
    public void run() {
        do {
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            BufferedImage image = null;

            if (webcam.isOpen()) {
                if ((image = webcam.getImage()) == null) {
                    continue;
                }

                doSomeStuff;
            }
        } while (true);
    }

    @Override
    public Thread newThread(Runnable r) {
        Thread t = new Thread(r, "example-runner");
        t.setDaemon(true);
        return t;
    }

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

但是我的JavaFX类没有启动/显示。我的代码出了什么问题？

Answer 1

我不熟悉你正在使用的网络摄像头API（所以我不知道这是否是唯一的错误），但你需要在AWT事件调度线程上创建你的Swing内容。目前，您正在FX应用程序线程上创建它。

您可以使用以下习语：

public class JavaFXDisplay extends Application {

    private WebcamCapture wc ;

    @Override
    public void init() throws Exception {
        super.init();
        FutureTask<WebcamCapture> launchWebcam = new FutureTask<>(WebcamCapture::new) ;
        SwingUtilities.invokeLater(launchWebcam);

        // block until webcam is started:
        wc = launchWebcam.get();
    }

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

        StackPane root = new StackPane();

        Rectangle rectangle = new Rectangle();
        rectangle.setWidth(500);
        rectangle.setHeight(500);

        Scene scene = new Scene(root, 1000, 1000);
        root.getChildren().addAll(rectangle);

        primaryStage.setScene(scene);
        primaryStage.show();

        scene.addEventFilter(MouseEvent.MOUSE_PRESSED, new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent mouseEvent) {
                wc.doSomething();
            }
        });
   }

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

供参考，这是一个仅限JavaFX的网络摄像头查看器。我在运行OS X Sierra（10.12.2）的MacBookPro上进行了测试，配备了带有摄像头的2011年27“Thunderbolt显示器。

import java.awt.Dimension;
import java.awt.image.BufferedImage;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;

import com.github.sarxos.webcam.Webcam;
import com.github.sarxos.webcam.WebcamResolution;

import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class FXWebCamViewer extends Application {

    private BlockingQueue<Image> imageQueue = new ArrayBlockingQueue<>(5);

    private Executor exec = Executors.newCachedThreadPool(runnable -> {
        Thread t = new Thread(runnable);
        t.setDaemon(true);
        return t ;
    });

    private Webcam webcam;

    @Override
    public void init() {
        webcam = Webcam.getWebcams().get(0);
        Dimension viewSize = WebcamResolution.QVGA.getSize();
        webcam.setViewSize(viewSize);
        webcam.open();
    }

    @Override
    public void start(Stage primaryStage) {
        ImageView imageView = new ImageView();

        StackPane root = new StackPane(imageView);
        imageView.fitWidthProperty().bind(root.widthProperty());
        imageView.fitHeightProperty().bind(root.heightProperty());
        imageView.setPreserveRatio(true);

        AnimationTimer updateImage = new AnimationTimer() {
            @Override
            public void handle(long timestamp) {
                Image image = imageQueue.poll();
                if (image != null) {
                    imageView.setImage(image);
                }
            }
        };
        updateImage.start();

        exec.execute(this::generateImages);

        Scene scene = new Scene(root, 600, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void generateImages() {
        while (! Thread.interrupted()) {
            try {
                if (webcam.isOpen() && webcam.isImageNew()) {
                    BufferedImage bimg = webcam.getImage();
                    if (bimg != null) {
                        imageQueue.put(SwingFXUtils.toFXImage(bimg, null));
                    }
                } else {
                    Thread.sleep(250);
                }
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }

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

同时运行javafx和swing应用程序

1 个答案: