I am working in a form in Vaadin, and I want to retrieve all the values selected in the components, but they are always empty.

This is the class were the components are defined and stored in a ArrayLIst to send to another classes and methods of the project.

public class MainView extends Div {

    ProjectConfiguration configuration = new ProjectConfiguration();

    private final List<String> visualizationList = new ArrayList<>(Arrays.asList("FAST", "REAL TIME"));
    private final List<String> resolutionList = new ArrayList<>(Arrays.asList("320 x 200", "640 x 400"));
    private final List<String> audioRate = new ArrayList<>(Arrays.asList("44100", "48000"));

    public void ShowForm() {

        ComboBoxs comboResolution = new ComboBoxs(resolutionList,"Video resolution","Select a resolution for the exported video");
        ComboBoxs comboVideoVisualization = new ComboBoxs(visualizationList,"Export visualization", "Select the visualization of the video export");
        ComboBoxs comboAudioRate = new ComboBoxs(audioRate,"Audio rate", "Select the audio rate for the video export");
        CheckStats checkStats = new CheckStats();
        ArrayList<Div> fieldValues = new ArrayList<Div>();
        fieldValues.add(comboResolution);
        fieldValues.add(comboVideoVisualization);
        fieldValues.add(comboAudioRate);
        fieldValues.add(checkStats);
        SubmitButton submitButton = new SubmitButton(configuration, fieldValues);
    }
}

And this Submit button is writting this configuration into a global POJO class.

public class SubmitButton extends Div {

public SubmitButton(ProjectConfiguration configuration, ArrayList<Div> fields) {
    Button submitButton = new Button("Create video");

    submitButton.addClickListener(clickEvent -> {
        submitConfiguration(configuration, fields);
    });
    add(submitButton);
}
private void submitConfiguration(ProjectConfiguration configuration, ArrayList<Div> fields) {
    new FieldGetter(configuration, fields);
}
}

And this same instance, if I send it to a new method outside to this class I always get an empty value.

public class FieldGetter {

    public FieldGetter(ProjectConfiguration configuration, ArrayList<Div> fields, String exportFileName) {
        log.info("Text 1 "   fields.get(0).getText());
        log.info("Text 2 "   fields.get(1).getText());
        log.info("Text 3 "   fields.get(2).getText());
        log.info("Text 4 "   fields.get(3).getText());
}}

All these components have information. All ComboBox is selected, and the Stats is clicked. What I'm doing wrong? Which method I need to use to get the selection. Thank you very much.

I'm adding the ComboBoxs class implemented, as requested.

@Route("combo")
public class ComboBoxs extends Div {

    public ComboBoxs(List<String> arrayList, String label, String helperText) {
        ComboBox<String> comboBox = new ComboBox<>(label);
        comboBox.setAllowCustomValue(true);
        comboBox.addCustomValueSetListener(e -> {
            String customValue = e.getDetail();
            arrayList.add(customValue);
            comboBox.setItems(arrayList);
            comboBox.setValue(customValue);
        });
        add(comboBox);
        comboBox.setItems(arrayList);
        comboBox.setHelperText(helperText);
    }
}

CodePudding user response：

Your FieldGetter is looking at the wrong place. Those Divs have no texts set (which might be what you assumed would happen by comboBox.setValue(customValue)).

Generally, your code is a bit convoluted. You don't need all those Divs and abstractions.

Try

public class HelloWorldView extends HorizontalLayout {

private final List<String> visualizationList = new ArrayList<>(Arrays.asList("FAST", "REAL TIME"));

public HelloWorldView() {
    ComboBox<String> comboBox = new ComboBox<>("Visualisation");
    comboBox.setAllowCustomValue(true);
    comboBox.addCustomValueSetListener(e -> {
        String customValue = e.getDetail();
        visualizationList.add(customValue);
        comboBox.setItems(visualizationList);
        comboBox.setValue(customValue);
    });
    add(comboBox);
    comboBox.setItems(visualizationList);

    Button printValues = new Button("Print");
    printValues.addClickListener(e -> {
        System.out.println(Arrays.toString(visualizationList.toArray(new String[0])));
        System.out.println("Value is now:"  comboBox.getValue() );
    });
    comboBox.addValueChangeListener(e-> System.out.println("Value changed from "    e.getOldValue()   " to "   e.getValue()));
    add(printValues);        }       }

Start, the program (I used the starter from start.vaadin.com), select "FAST", then delete "FAST", enter "Slow" and hit <return/enter>. Then click the print button.

The output will look like this:

Value changed from null to FAST
Value changed from FAST to null
Value changed from null to Slow
[FAST, REAL TIME, Slow]
Value is now:Slow

Hope this helps!