JavaFXでのDnDの例

ImageViewer.java

package imageviewer;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.DragEvent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

/**
 * JavaFX でのDnDの例。
 * 画像ファイルをドロップすると表示する。
 */
public class ImageViewer extends Application {

    private int currentIndex = -1;
    private List<String> imageFiles = new ArrayList<String>();
    private ImageView currentImageView;

    public static void main(String[] args) {
        launch(args);
    }
    
    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("Image Viewer");
        final Group root = new Group();
        final Scene scene = new Scene(root, 550, 400, Color.BLACK);

        currentImageView = new ImageView();
        currentImageView.setPreserveRatio(true);
        currentImageView.fitWidthProperty().bind(scene.widthProperty());

        final HBox pictureRegion = new HBox();
        pictureRegion.getChildren().add(currentImageView);
        root.getChildren().add(pictureRegion);

        scene.setOnDragOver(new EventHandler<DragEvent>() {
            @Override
            public void handle(DragEvent event) {
                Dragboard db = event.getDragboard();
                if (db.hasFiles()) {
                    event.acceptTransferModes(TransferMode.COPY);
                }
                event.consume();
            }
        });
        scene.setOnDragDropped(new EventHandler<DragEvent>() {
            @Override
            public void handle(DragEvent event) {
                Dragboard db = event.getDragboard();
                boolean success = false;
                if (db.hasFiles()) {
                    success = true;
                    String filePath = null;
                    for (File file : db.getFiles()) {
                        filePath = file.getAbsolutePath();
                        currentIndex++;
                        imageFiles.add(currentIndex, filePath);
                        System.out.println("file: " + filePath);
                        System.out.println("current index: " + currentIndex);
                    }
                    Image currentImage = new Image(filePath);
                    currentImageView.setImage(currentImage);
                }
                event.setDropCompleted(success);
                event.consume();
            }
        });

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