CODEWITHSUNDEEP
javafxdialog
Askiin
Askiin

Reputation: 43

JavaFX - creating custom dialogs using fxml

I'm new in javafx and I was trying to create custom dialogs/alerts. The thing is that I'm using Scene Builder to design the GUI, and I want to modify the dialog each time I load the fxml file (i.e change the title, label text, etc.), so I wanted to know if there's a way to send parameters and modify the stage/scene, or any other way I can achieve this.

To be more specific, let's say there's an error I want to handle anywhere in my program, so I load a new fxml file that represents the error dialog I created, and I modify the components inside it, depending on the type of error I need to handle, similar to, for example, JOptionPane.showMessageDialog(...) in swing.

Upvotes: 4

Views: 14881

Answers (1)

James_D
James_D

Reputation: 209225

For the use case you describe, you can just use the Dialog API, or the specialized Alert class that is part of that.

For the more general question you ask:

I wanted to know if there's a way to send parameters and change the stage/scene

the way to do this is to use the custom component mechanism described in the documentation.

In short, make a subclass of the UI type you need that loads the FXML file, and defines the properties you need, e.g.

public class ExceptionPane extends BorderPane {

    private final ObjectProperty<Exception> exception ;

    public ObjectProperty<Exception> exceptionProperty() {
        return exception ;
    }

    public final Exception getException() {
        return exceptionProperty().get();
    }

    public final void setException(Exception exception) {
        exceptionProperty().set(exception);
    }

    @FXML
    private final TextArea stackTrace ;
    @FXML
    private final Label message ;

    public ExceptionPane() throws Exception {

        FXMLLoader loader = new FXMLLoader(getClass().getResource("path/to/fxml"));
        loader.setRoot(this);
        loader.setController(this);

        loader.load();

        exception.addListener((obs, oldException, newException) -> {
            if (newException == null) {
                message.setText(null);
                stackTrace.setText(null);
            } else {
                message.setText(newException.getMessage());
                StringWriter sw = new StringWriter();
                newException.printStackTrace(new PrintWriter(sw));
                stackTrace.setText(sw.toString());
            }
        });
    }
}

Then define the FXML using a "dynamic root":

<!-- imports etc -->

<fx:root type="BorderPane" ...>

    <center>
        <TextArea fx:id="stackTrace" editable="false" wrapText="false" />
    </center>
    <top>
        <Label fx:id="message" />
    </top>
</fx:root>

Now you can use this directly in either Java or in FXML:

try {
    // some code...
} catch (Exception exc) {
    ExceptionPane excPane = new ExceptionPane();
    excPane.setException(exc);
    Stage stage = new Stage();
    stage.setScene(new Scene(excPane));
    stage.show();
}

or 

<fx:define fx:id="exc"><!-- define exception somehow --></fx:define>

<ExceptionPane exception="${exc}" />

Upvotes: 5

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