未调用 JavaFX FXML Controller 初始化方法

Question

我正在尝试从一个简单的 ArrayList 的内容中填充 ListView。这是我的

Controller.java 文件:

package design;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.ResourceBundle;

import javafx.beans.property.ListProperty;
import javafx.beans.property.SimpleListProperty;
import javafx.collections.FXCollections;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
import javafx.scene.control.ListView;

public class Controller {

    @FXML private Button buttontest;
    @FXML private ListView<Song> listViewofSongs;

    protected List<Song> songList = new ArrayList<>();
    protected ListProperty<Song> listProperty = new SimpleListProperty<Song>();
    Song Language = new Song("Peter", "myalbum", "yes", 2010);

    public void addSong(Song song){
        songList.add(song);
    }

    public void initialize(URL url, ResourceBundle rb) {
            addSong(Language);
            listViewofSongs.setItems(FXCollections.observableList(songList));
     }



}

这是我的 Style.fxml 文件:

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

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.ListView?>
<?import javafx.scene.control.Separator?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.Pane?>
<?import javafx.scene.layout.RowConstraints?>
<?import javafx.scene.text.Font?>

<GridPane prefHeight="499.0" prefWidth="700.0" xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1" fx:controller="design.Controller">
   <columnConstraints>
      <ColumnConstraints />
      <ColumnConstraints />
      <ColumnConstraints maxWidth="0.0" minWidth="0.0" prefWidth="0.0" />
      <ColumnConstraints maxWidth="0.0" minWidth="0.0" prefWidth="0.0" />
   </columnConstraints>
   <rowConstraints>
      <RowConstraints />
      <RowConstraints />
      <RowConstraints maxHeight="0.0" minHeight="0.0" prefHeight="0.0" />
      <RowConstraints maxHeight="10.0" minHeight="0.0" prefHeight="0.0" />
      <RowConstraints maxHeight="10.0" minHeight="0.0" prefHeight="0.0" />
      <RowConstraints fillHeight="false" maxHeight="500.0" minHeight="10.0" prefHeight="240.0" />
      <RowConstraints fillHeight="false" maxHeight="500.0" minHeight="10.0" prefHeight="149.0" />
      <RowConstraints fillHeight="false" maxHeight="500.0" minHeight="10.0" prefHeight="50.0" />
   </rowConstraints>
   <children>
      <Pane prefHeight="64.0" prefWidth="700.0">
         <children>
            <Label layoutX="259.0" layoutY="14.0" text="Song Library">
               <font>
                  <Font name="Consolas Bold" size="26.0" />
               </font>
               <padding>
                  <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
               </padding>
            </Label>
         </children>
      </Pane>
      <Separator prefWidth="200.0" GridPane.rowIndex="4" />
      <ListView fx:id="listViewofSongs" editable="true" prefHeight="239.0" prefWidth="700.0" GridPane.rowIndex="5" />

      <Label text="Song Info" GridPane.halignment="CENTER" GridPane.rowIndex="6" GridPane.valignment="TOP">
         <GridPane.margin>
            <Insets bottom="10.0" />
         </GridPane.margin>
         <font>
            <Font name="Consolas" size="22.0" />
         </font>
         <padding>
            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
         </padding>
      </Label>
      <Label GridPane.rowIndex="6" />
      <Label text="NAME" GridPane.rowIndex="6">
         <font>
            <Font name="Calibri" size="19.0" />
         </font>
         <GridPane.margin>
            <Insets bottom="60.0" left="200.0" />
         </GridPane.margin>
      </Label>
      <TextField maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="25.0" prefWidth="343.0" GridPane.rowIndex="6">
         <GridPane.margin>
            <Insets bottom="60.0" left="275.0" />
         </GridPane.margin>
      </TextField>
      <Label text="ARTIST" GridPane.rowIndex="6">
         <font>
            <Font name="Calibri" size="19.0" />
         </font>
         <GridPane.margin>
            <Insets left="200.0" />
         </GridPane.margin>
      </Label>
      <TextField maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="25.0" prefWidth="343.0" GridPane.rowIndex="6">
         <GridPane.margin>
            <Insets left="275.0" />
         </GridPane.margin>
      </TextField>
      <Label text="ALBUM" GridPane.rowIndex="6">
         <font>
            <Font name="Calibri" size="19.0" />
         </font>
         <GridPane.margin>
            <Insets bottom="-60.0" left="200.0" />
         </GridPane.margin>
      </Label>
      <TextField maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="25.0" prefWidth="343.0" GridPane.rowIndex="6">
         <GridPane.margin>
            <Insets bottom="-60.0" left="275.0" />
         </GridPane.margin>
      </TextField>
      <Label text="YEAR" GridPane.rowIndex="6">
         <font>
            <Font name="Calibri" size="19.0" />
         </font>
         <GridPane.margin>
            <Insets bottom="-120.0" left="200.0" />
         </GridPane.margin>
      </Label>
      <TextField maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="25.0" prefWidth="343.0" GridPane.rowIndex="6">
         <GridPane.margin>
            <Insets bottom="-120.0" left="275.0" />
         </GridPane.margin>
      </TextField>
      <Button mnemonicParsing="false" prefHeight="28.0" prefWidth="75.0" text="ADD" GridPane.rowIndex="7">
         <GridPane.margin>
            <Insets left="125.0" />
         </GridPane.margin>
         <font>
            <Font name="Corbel" size="15.0" />
         </font>
      </Button>
      <Button mnemonicParsing="false" prefHeight="28.0" prefWidth="75.0" text="EDIT" GridPane.rowIndex="7">
         <font>
            <Font name="Corbel" size="15.0" />
         </font>
         <GridPane.margin>
            <Insets left="325.0" />
         </GridPane.margin>
      </Button>
      <Button mnemonicParsing="false" prefHeight="28.0" prefWidth="75.0" text="DELETE" GridPane.rowIndex="7">
         <font>
            <Font name="Corbel" size="15.0" />
         </font>
         <GridPane.margin>
            <Insets left="525.0" />
         </GridPane.margin>
      </Button>
      <Separator orientation="VERTICAL" prefHeight="200.0" GridPane.rowIndex="7">
         <GridPane.margin>
            <Insets left="250.0" />
         </GridPane.margin>
         <padding>
            <Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
         </padding>
      </Separator>
   </children>
</GridPane>

程序运行，但是我输入的歌曲没有出现在ListView中(而且Song类确实有toString方法)。

我能做什么？

Answer 1

问题是 Controller 没有按照提问者的预期进行初始化。

Java 8 中 FXMLLoader 的操作有点奇怪。

1. 如果您在 Controller 中定义了一个无参数的 initialize() 方法并且没有实现 Initializable接口(interface)，那么 FXML 加载器仍然会自动调用初始化方法。

2. 相反，如果您在 Controller 中定义参数化的public void initialize(URL url, ResourceBundle rb) 方法，则 FXML 加载器将不会自动调用初始化方法除非 你的 Controller 也实现了 Initializable界面。

由于问题中的代码使用了参数化初始化方法并且没有实现 Initializable，因此没有进行初始化。

---

FXML 中的参数化初始化方法应通过@FXML 注释注入(inject)参数来替换，有关更多详细信息，请参见:

• What is "automatic injection of location and resources properties into the controller" in JavaFX?

  @FXML 
  private ResourceBundle resources;
  
  @FXML 
  private URL location;