JavaFX：从 FXML 加载场景，但从代码添加标签

Question

我有下面的FXML，它是我在另一个场景中按下按钮时加载的

<GridPane fx:id="gridPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" styleClass="root" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="VMProvOpenstack.Controller">
    <columnConstraints>
        <ColumnConstraints hgrow="SOMETIMES" maxWidth="295.0" minWidth="10.0" prefWidth="162.0" />
        <ColumnConstraints hgrow="SOMETIMES" maxWidth="295.0" minWidth="10.0" prefWidth="162.0" />
        <ColumnConstraints hgrow="SOMETIMES" maxWidth="358.0" minWidth="0.0" prefWidth="358.0" />
        <ColumnConstraints hgrow="SOMETIMES" maxWidth="450.0" minWidth="0.0" prefWidth="0.0" />
    </columnConstraints>
    <rowConstraints>
        <RowConstraints maxHeight="166.0" minHeight="10.0" prefHeight="96.0" vgrow="SOMETIMES" />
        <RowConstraints maxHeight="238.0" minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
        <RowConstraints maxHeight="305.0" minHeight="10.0" prefHeight="257.0" vgrow="SOMETIMES" />
    </rowConstraints>
    <children>
        <Region prefHeight="36.0" prefWidth="538.0" style="-fx-background-color: brown;" GridPane.rowIndex="1">
            <effect>
                <Blend />
            </effect>
        </Region>
        <Region prefHeight="200.0" prefWidth="200.0" style="-fx-background-color: brown;" GridPane.columnIndex="1" GridPane.rowIndex="1" />
        <Region layoutX="10.0" layoutY="112.0" prefHeight="36.0" prefWidth="538.0" style="-fx-background-color: brown;" GridPane.columnIndex="2" GridPane.rowIndex="1">
            <effect>
                <Blend />
            </effect>
        </Region>
        <Label fx:id="loggedinUser" contentDisplay="RIGHT" prefHeight="21.0" prefWidth="199.0" text="Loged in as:  " textFill="green" GridPane.columnIndex="2" GridPane.rowIndex="0" />
        <Label fx:id="ipopenstack" contentDisplay="RIGHT" prefHeight="21.0" prefWidth="199.0" text="IP : 192.168.131.132" textFill="#eb0f0f" translateX="-40.0" GridPane.columnIndex="2" GridPane.rowIndex="2" />
    </children>
</GridPane>

代码是：

@FXM Label ipopenstack=new Label();
@FXML GridPane gridPane=new GridPane();
//...
Stage stageTheEventSourceNodeBelongs = (Stage)((Node)event.getSource()).getScene().getWindow();
try {
    Scene scene= new Scene(FXMLLoader.load(getClass().getResource("my.fxml")),700,500);
    stageTheEventSourceNodeBelongs.setScene(scene);
} catch (IOException e) {
    e.printStackTrace();
}

如果我这样做，一切都显示得很好。但我想在这个场景中添加一个带有动态消息的标签，并且仍然保留fxml中的所有内容。如果我这样做，其中消息是字符串

Label ipL=new Label(message);                  
gridPane.add(ipL, 2, 2);
scene.setRoot(gridPane);

在< code>setScene之前，它将添加我的标签，但不添加来自fxml的元素。

有什么建议吗？谢谢

Answer 1

首先尝试从场景中获取窗格，然后更新

Parent p=scene.getRoot();
// Navigate to the appropriate pane object
//the try adding the label to the pane object
pane.add(ipL, 2, 2);

并确保所有这些都是在 JavaFx 线程（工作线程）中完成的

或者，您可以做的另一件事是，当您需要更新消息时，请立即添加并隐藏标签，只需使用消息更新标签并关闭其隐藏

Answer 2

永远不要初始化@FXML-注入字段。你应该

@FXML Label ipopenstack ;
@FXML GridPane gridPane ;

代替

@FXML Label ipopenstack=new Label();
@FXML GridPane gridPane=new GridPane();