当用FXML加载JavaFX中的FXML文件时，如何在第二个控制器上自动启动动作事件？

Question

public void startNewScene() throws IOException {
    root = FXMLLoader.load(getClass().getResource("FXML.fxml"));
    Scene scene = new Scene(root);
    Stage stage = new Stage();
    stage.setScene(scene);
    stage.show();
}

public class MyController implements Initializable {
    @FXML private Button button;
    @FXML private Label label;

    @FXML
    @Override
    public void initialize(URL location, ResourceBundle resources) {
        button.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent event) {
               label.setText("hello there,  you clicked me"); 
            }
    }
);
    }
}

FXML文件：

<GridPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="ciacv.MyController">
  <columnConstraints>
    <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
    <ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
  </columnConstraints>
  <rowConstraints>
    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
    <RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
  </rowConstraints>
   <children>
      <Label fx:id="label"  />
      <Button fx:id="button" mnemonicParsing="false"  text="Button" GridPane.columnIndex="1" />
   </children>
</GridPane>

Answer 1

fxml中按钮的fx:id是butn1，与在控制器中一样，您正在尝试用声明注入按钮

@FXML private Button button;

您需要使用在fxml中声明的fx:id来正确地将对象注入到其引用中，即。

@FXML private Button butn1;

编辑-根据注释

public void startNewScene() throws IOException {
    root = FXMLLoader.load(getClass().getResource("FXML.fxml"));
    Scene scene = new Scene(root);
    Stage stage = new Stage();
    stage.setScene(scene);
    stage.show();
}

编辑-2

不，您还没有编写任何内容来在加载fxml时设置标签中的文本。

你刚刚写了

label.setText("hello there,  you clicked me");` 

@Override
public void initialize(URL location, ResourceBundle resources) {
    // Set Label's text intialize() is called
    label.setText("Helll There...");`
    // Set Label's text on Button's action
    button.setOnAction(new EventHandler<ActionEvent>() {
        @Override
        public void handle(ActionEvent event) {
           label.setText("hello there,  you clicked me"); 
        }
    }
}