JavaFX不能拖放

Question

I have this interface:

@Override
public void start(Stage primaryStage){

    Text fileText = new Text("File:");

    TextField fileField = new TextField();
    fileField.setDisable(true);
    fileField.setMinWidth(250);
    fileField.setOnDragDropped(e -> {

        Dragboard db = e.getDragboard();
        boolean success = false;
        if (db.hasFiles()){

            fileField.setText(db.getFiles().toString());
            success = true;

        }

        e.setDropCompleted(success);
        e.consume();

    });

    Button clearButton = new Button("Clear");
    clearButton.setOnMouseClicked(e -> fileField.setText(""));

    HBox hboxFile = new HBox();
    hboxFile.setAlignment(Pos.CENTER_LEFT);
    hboxFile.getChildren().addAll(fileText, fileField, clearButton);

    HBox.setMargin(fileText, new Insets(10));
    HBox.setMargin(fileField, new Insets(10, 10, 10, 0));
    HBox.setMargin(clearButton, new Insets(10, 10, 10, 0));

    primaryStage.setScene(new Scene(hboxFile));
    primaryStage.sizeToScene();
    primaryStage.centerOnScreen();
    primaryStage.show();

}

I want to activate drag and drop for TextField , when I drop an file over input, will appear location of file.

My problem is I cannot drop anything in interface.

When I drag file over input appear interdict sign:

This sign is present all over interface when I try to drag a file.

Answer 1

You need to set the onDragOver property to enable copying/moving of the file. Like so:

fileField.setOnDragOver((e) -> {
    if (e.getGestureSource() != fileField && e.getDragboard().hasFiles()) {
        e.acceptTransferModes(TransferMode.COPY_OR_MOVE);
    }
    e.consume();
});

Furthermore, the line fileField.setDisable(true); disables you from being able to drop files on your TextField. Instead, do:

fileField.setEditable(false);

This will allow you to drag/drop files to set the text, but it won't let a user edit the text manually.
The complete testing code:

public class TestApp extends Application
{
    public static void main(String[] args)
    {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {

        Text fileText = new Text("File:");

        TextField fileField = new TextField();
        fileField.setMinWidth(250);
        fileField.setPromptText("Drop file here");
        fileField.setOnDragOver((e) -> {
            if (e.getGestureSource() != fileField && e.getDragboard().hasFiles()) {
                e.acceptTransferModes(TransferMode.COPY_OR_MOVE);
            }
            e.consume();
        });
        fileField.setEditable(false);
        fileField.setOnDragDropped(e -> {
            Dragboard db = e.getDragboard();
            boolean success = false;
            if (db.hasFiles()) {
                fileField.setText(db.getFiles().toString());
                success = true;
            }
            e.setDropCompleted(success);
            e.consume();
        });

        Button clearButton = new Button("Clear");
        clearButton.setOnMouseClicked(e -> fileField.setText(""));

        HBox hboxFile = new HBox();
        hboxFile.setAlignment(Pos.CENTER_LEFT);
        hboxFile.getChildren().addAll(fileText, fileField, clearButton);

        HBox.setMargin(fileText, new Insets(10));
        HBox.setMargin(fileField, new Insets(10, 10, 10, 0));
        HBox.setMargin(clearButton, new Insets(10, 10, 10, 0));

        primaryStage.setScene(new Scene(hboxFile));
        primaryStage.sizeToScene();
        primaryStage.centerOnScreen();
        primaryStage.show();
    }
}

The result:

When dropped: