如何使用FXML在JavaFX 2.0中创建自定义组件？

Question

我似乎无法找到关于这个主题的任何材料.为了给出一个更具体的例子,假设我想创建一个结合了复选框和标签的简单组件.然后,使用此自定义组件的实例填充ListView.

更新:请参阅我的答案以获取完整代码

更新2:有关最新教程,请参阅官方文档.在2.2中添加了许多新内容.最后,FXML简介涵盖了您需要了解的有关FXML的所有内容.

更新3:Hendrik Ebbers撰写了一篇关于自定义UI控件的非常有用的博文.

Answer 1

更新:有关最新教程,请参阅官方文档.在2.2中添加了许多新内容.此外,FXML简介涵盖了您需要了解的有关FXML的所有内容.最后,Hendrik Ebbers撰写了一篇关于自定义UI控件的非常有用的博文.

之后环视了几天API,并通过一些文档阅读(简介FXML,开始使用FXML 地产结合,FXML的未来),我想出了一个相当明智的解决办法.我从这个小实验得知的信息至少直前部件是一个控制器(带FX声明:控制器FXML)的实例由持有FXMLLoader装入的FXML文件......最糟糕的是,这一重要的事实在我看到的所有文档中只提到一个地方:

控制器通常仅对创建它的FXML加载器可见

所以,请记住,以编程方式(从Java代码)获得到在与FXML声明的控制器的实例的引用fx:controller使用FXMLLoader.getController() (请参阅下面的ChoiceCell类的实现了一个完整的例子).

另外需要注意的是,Property.bindBiderctional()会将调用属性的值设置为作为参数传入的属性的值.鉴于两个布尔属性target(最初的设置false)和source(初始设置为true呼叫)target.bindBidirectional(source)将设置的值target来true.显然,对任一属性的任何后续更改都将更改其他属性的值(target.set(false)将导致值source设置为false):

BooleanProperty target = new SimpleBooleanProperty();//value is false
BooleanProperty source = new SimpleBooleanProperty(true);//value is true
target.bindBidirectional(source);//target.get() will now return true
target.set(false);//both values are now false
source.set(true);//both values are now true

无论如何,这里是完整的代码,演示了FXML和Java如何协同工作(以及一些其他有用的东西)

包装结构:

com.example.javafx.choice
  ChoiceCell.java
  ChoiceController.java
  ChoiceModel.java
  ChoiceView.fxml
com.example.javafx.mvc
  FxmlMvcPatternDemo.java
  MainController.java
  MainView.fxml
  MainView.properties

FxmlMvcPatternDemo.java

package com.example.javafx.mvc;

import java.util.ResourceBundle;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class FxmlMvcPatternDemo extends Application
{
    public static void main(String[] args) throws ClassNotFoundException
    {
        Application.launch(FxmlMvcPatternDemo.class, args);
    }

    @Override
    public void start(Stage stage) throws Exception
    {
        Parent root = FXMLLoader.load
        (
            FxmlMvcPatternDemo.class.getResource("MainView.fxml"),
            ResourceBundle.getBundle(FxmlMvcPatternDemo.class.getPackage().getName()+".MainView")/*properties file*/
        );

        stage.setScene(new Scene(root));
        stage.show();
    }
}

MainView.fxml

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

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

<VBox
    xmlns:fx="http://javafx.com/fxml"
    fx:controller="com.example.javafx.mvc.MainController"

    prefWidth="300"
    prefHeight="400"
    fillWidth="false"
>
    <children>
        <Label text="%title" />
        <ListView fx:id="choicesView" />
        <Button text="Force Change" onAction="#handleForceChange" />
    </children>
</VBox>

MainView.properties

title=JavaFX 2.0 FXML MVC demo

MainController.java

package com.example.javafx.mvc;

import com.example.javafx.choice.ChoiceCell;
import com.example.javafx.choice.ChoiceModel;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.collections.FXCollections;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.util.Callback;

public class MainController implements Initializable
{
    @FXML
    private ListView<ChoiceModel> choicesView;

    @Override
    public void initialize(URL url, ResourceBundle rb)
    {
        choicesView.setCellFactory(new Callback<ListView<ChoiceModel>, ListCell<ChoiceModel>>()
        {
            public ListCell<ChoiceModel> call(ListView<ChoiceModel> p)
            {
                return new ChoiceCell();
            }
        });
        choicesView.setItems(FXCollections.observableArrayList
        (
            new ChoiceModel("Tiger", true),
            new ChoiceModel("Shark", false),
            new ChoiceModel("Bear", false),
            new ChoiceModel("Wolf", true)
        ));
    }

    @FXML
    private void handleForceChange(ActionEvent event)
    {
        if(choicesView != null && choicesView.getItems().size() > 0)
        {
            boolean isSelected = choicesView.getItems().get(0).isSelected();
            choicesView.getItems().get(0).setSelected(!isSelected);
        }
    }
}

ChoiceView.fxml

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

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

<HBox
    xmlns:fx="http://javafx.com/fxml"

    fx:controller="com.example.javafx.choice.ChoiceController"
>
    <children>
        <CheckBox fx:id="isSelectedView" />
        <Label fx:id="labelView" />
    </children>
</HBox>

ChoiceController.java

package com.example.javafx.choice;

import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;

public class ChoiceController
{
    private final ChangeListener<String> LABEL_CHANGE_LISTENER = new ChangeListener<String>()
    {
        public void changed(ObservableValue<? extends String> property, String oldValue, String newValue)
        {
            updateLabelView(newValue);
        }
    };

    private final ChangeListener<Boolean> IS_SELECTED_CHANGE_LISTENER = new ChangeListener<Boolean>()
    {
        public void changed(ObservableValue<? extends Boolean> property, Boolean oldValue, Boolean newValue)
        {
            updateIsSelectedView(newValue);
        }
    };

    @FXML
    private Label labelView;

    @FXML
    private CheckBox isSelectedView;

    private ChoiceModel model;

    public ChoiceModel getModel()
    {
        return model;
    }

    public void setModel(ChoiceModel model)
    {
        if(this.model != null)
            removeModelListeners();
        this.model = model;
        setupModelListeners();
        updateView();
    }

    private void removeModelListeners()
    {
        model.labelProperty().removeListener(LABEL_CHANGE_LISTENER);
        model.isSelectedProperty().removeListener(IS_SELECTED_CHANGE_LISTENER);
        isSelectedView.selectedProperty().unbindBidirectional(model.isSelectedProperty())
    }

    private void setupModelListeners()
    {
        model.labelProperty().addListener(LABEL_CHANGE_LISTENER);
        model.isSelectedProperty().addListener(IS_SELECTED_CHANGE_LISTENER);
        isSelectedView.selectedProperty().bindBidirectional(model.isSelectedProperty());
    }

    private void updateView()
    {
        updateLabelView();
        updateIsSelectedView();
    }

    private void updateLabelView(){ updateLabelView(model.getLabel()); }
    private void updateLabelView(String newValue)
    {
        labelView.setText(newValue);
    }

    private void updateIsSelectedView(){ updateIsSelectedView(model.isSelected()); }
    private void updateIsSelectedView(boolean newValue)
    {
        isSelectedView.setSelected(newValue);
    }
}

ChoiceModel.java

package com.example.javafx.choice;

import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

public class ChoiceModel
{
    private final StringProperty label;
    private final BooleanProperty isSelected;

    public ChoiceModel()
    {
        this(null, false);
    }

    public ChoiceModel(String label)
    {
        this(label, false);
    }

    public ChoiceModel(String label, boolean isSelected)
    {
        this.label = new SimpleStringProperty(label);
        this.isSelected = new SimpleBooleanProperty(isSelected);
    }

    public String getLabel(){ return label.get(); }
    public void setLabel(String label){ this.label.set(label); }
    public StringProperty labelProperty(){ return label; }

    public boolean isSelected(){ return isSelected.get(); }
    public void setSelected(boolean isSelected){ this.isSelected.set(isSelected); }
    public BooleanProperty isSelectedProperty(){ return isSelected; }
}

ChoiceCell.java

package com.example.javafx.choice;

import java.io.IOException;
import java.net.URL;
import javafx.fxml.FXMLLoader;
import javafx.fxml.JavaFXBuilderFactory;
import javafx.scene.Node;
import javafx.scene.control.ListCell;

public class ChoiceCell extends ListCell<ChoiceModel>
{
    @Override
    protected void updateItem(ChoiceModel model, boolean bln)
    {
        super.updateItem(model, bln);

        if(model != null)
        {
            URL location = ChoiceController.class.getResource("ChoiceView.fxml");

            FXMLLoader fxmlLoader = new FXMLLoader();
            fxmlLoader.setLocation(location);
            fxmlLoader.setBuilderFactory(new JavaFXBuilderFactory());

            try
            {
                Node root = (Node)fxmlLoader.load(location.openStream());
                ChoiceController controller = (ChoiceController)fxmlLoader.getController();
                controller.setModel(model);
                setGraphic(root);
            }
            catch(IOException ioe)
            {
                throw new IllegalStateException(ioe);
            }
        }
    }
}

Answer 2

对于JavaFx 2.1,您可以通过以下方式创建自定义FXML控件组件:

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

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import customcontrolexample.myCommponent.*?>

<VBox xmlns:fx="http://javafx.com/fxml" fx:controller="customcontrolexample.FXML1Controller">
    <children>
        <MyComponent welcome="1234"/>
    </children>
</VBox>

组件代码:

MyComponent.java

package customcontrolexample.myCommponent;

import java.io.IOException;
import javafx.beans.property.StringProperty;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.layout.Pane;
import javafx.util.Callback;

public class MyComponent extends Pane {

    private Node view;
    private MyComponentController controller;

    public MyComponent() {
        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("myComponent.fxml"));
        fxmlLoader.setControllerFactory(new Callback<Class<?>, Object>() {
            @Override
            public Object call(Class<?> param) {
                return controller = new MyComponentController();
            }
        });
        try {
            view = (Node) fxmlLoader.load();

        } catch (IOException ex) {
        }
        getChildren().add(view);
    }

    public void setWelcome(String str) {
        controller.textField.setText(str);
    }

    public String getWelcome() {
        return controller.textField.getText();
    }

    public StringProperty welcomeProperty() {
        return controller.textField.textProperty();
    }
}

MyComponentController.java

package customcontrolexample.myCommponent;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TextField;

public class MyComponentController implements Initializable {

    int i = 0;
    @FXML
    TextField textField;

    @FXML
    protected void doSomething() {
        textField.setText("The button was clicked #" + ++i);
    }

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        textField.setText("Just click the button!");
    }
}

myComponent.fxml

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

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

<VBox xmlns:fx="http://javafx.com/fxml" fx:controller="customcontrolexample.myCommponent.MyComponentController">
  <children>
    <TextField fx:id="textField" prefWidth="200.0" />
    <Button mnemonicParsing="false" onAction="#doSomething" text="B" />
  </children>
</VBox>

此代码需要检查是否没有内存泄漏.