JavaFX & FXML: how do I set the default selected item in a ChoiceBox in FXML?

问题

I have the following FXML:

<ChoiceBox>
    <items>
        <FXCollections fx:factory="observableArrayList">
            <String fx:value="2 minutes" />
            <String fx:value="5 minutes" />
            <String fx:value="15 minutes" />
        </FXCollections>
    </items>
</ChoiceBox>

But in the GUI it just shows a ChoiceBox with a default of nothing. I would like the first element in the list to be the default, and for a choice of "null" or nothing to be prohibited.

How do I accomplish this?

回答1:

I added the value attribute to the ChoiceBox tag, and that worked.

<ChoiceBox value="2 minutes">
    <items>
        <FXCollections fx:factory="observableArrayList">
            <String fx:value="2 minutes" />
            <String fx:value="5 minutes" />
            <String fx:value="15 minutes" />
        </FXCollections>
    </items>
</ChoiceBox>

回答2:

First, you should import your needed value model, like Crowell answer, you should import like this in your fxml header:

<?import javafx.collections.*?>

Second, if you want's import your own model, import it first and then like this:

<?import com.zzg.mybatis.generator.model.*?>
....

<ChoiceBox layoutX="24.0" layoutY="14.0" prefWidth="150.0">
      <items>
            <FXCollections fx:factory="observableArrayList">
                  <DatabaseDTO name="MySQL" value="1"></DatabaseDTO>
                  <DatabaseDTO name="Oracle" value="2"></DatabaseDTO>
            </FXCollections>
      </items>
</ChoiceBox>

回答3:

@Groostav: In case we programmatically "know" the value that should appear as selected (for example, we landed in an edit form), we can do the following:

1) Add a new item with index 0 (that is, the element we need to show as selected):

myChoiceBox.getItems().add(0, ItemObtainedProgrammatically);

2) Show the item as selected (since we already know it's at position 0):

myChoiceBox.getSelectionModel().select(0);

Probably this qualifies as a dirty hack, but it works. The con: You have the same item twice in your choicebox

来源：https://stackoverflow.com/questions/18244943/javafx-fxml-how-do-i-set-the-default-selected-item-in-a-choicebox-in-fxml

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javafx-2

javafx

fxml