我正在通过Scene Builder开发JavaFX项目.
我创建了一个很长的FXML文件(我只报告了一个片段)和关联的控制器.此外,我编写了Application类：

public class Main extends Application {
    @Override
    public void start(Stage stage) {
        Parent root;
        try {
            root = FXMLLoader.load(getClass().getResource("myfxml.fxml"));
        } catch (IOException e) {
            e.printStackTrace();
            return;
        }

        Scene scene = new Scene(root);

        stage.setTitle("Popolamento dati Ambasciata");
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

FXML：

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>

<GridPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="600.0" prefWidth="1150.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.FXController">
    ...
<children>
        <Button id="addobject" mnemonicParsing="false" onAction="#addobject" text="Add Object" GridPane.columnIndex="1" GridPane.halignment="CENTER" GridPane.rowIndex="10" />
        <TextField id="objectname" GridPane.columnIndex="1" GridPane.columnSpan="2" GridPane.rowIndex="1" />

控制器：

public class FXController {

@FXML Button addobject;
@FXML TextField objectname;

@FXML
public void addobject() {
    objectname.getText();
}
}

}

该应用程序正确启动,并调用了事件处理程序,但是在访问TextField对象名时,它为null.
我在哪里做错了？

解决方法:

您应该使用fx：id属性而不是id.

如果您查看文档here：

Assigning an fx:id value to an element creates a variable in the document’s namespace that can later be referred to by variable dereference attributes

请注意,您仍然可以使用idattribute：

Additionally, if the object’s type defines an “id” property, this value will also be passed to the objects setId() method.

因此,在您的情况下：

<Button fx:id="addobject" ... />
<TextField fx:id="objectname" ... />