[英]JavaFX - Wrapping FXML to Java Class Controller
我有一個具有TreeView控件的FXML文件:
<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="500.0" xmlns:fx="http://javafx.com/fxml" fx:controller="test.MyControllerClass">
<TreeView fx:id="locationTreeView" layoutX="12.0" layoutY="158.0" prefHeight="193.0" prefWidth="471.0" />
然后我的Java類控制器需要用這個TreeView包裝並動態添加TreeItem。 這就是問題,它沒有加載那些TreeItem。 這是我的控制器下面的測試代碼:
public class MyControllerClass extends Application {
@FXML
private TreeView<String> locationTreeView;
@Override
public void start(Stage stage) throws Exception {
stage.initStyle(StageStyle.TRANSPARENT);
stage.getIcons().add(new Image(getClass().getResourceAsStream("myIcon.png")));
Parent root = FXMLLoader.load(getClass().getResource("myInterface.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
loadTreeItems();
stage.show();
}
// Just a simple example that still doesn't works
private void loadTreeItems() {
try {
TreeItem<String> root = new TreeItem<String>("Root Node");
root.setExpanded(true);
root.getChildren().addAll(
new TreeItem<String>("Item 1"),
new TreeItem<String>("Item 2"),
new TreeItem<String>("Item 3")
);
locationTreeView = new TreeView<String>(root);
} catch (Exception exc) {
System.out.println("Error: " + exc.getMessage());
}
}
public static void main(String[] args) {
launch(args);
}
}
任何想法為什么它不工作?
您的應用程序不起作用的原因有以下幾種:
您的應用程序當前結構化的方式將是:
MyControllerClass
的實例(並調用它的start
方法)。 myInterface.fxml
文件時 , FXMLLoader
都會創建另一個 MyControllerClass
實例 。 FXMLLoader
將創建一個新的TreeView
實例,並在它創建的新 MyControllerClass
實例的locationTreeView
成員上執行FXML注入。 FXMLLoader
將嘗試在新的MyControllerClass
上調用initialize
方法(其中沒有)。 FXMLLoader
不會在新的 MyControllerClass
上調用start
方法。 MyControllerClass
上的原始start
方法調用將繼續處理並創建另一個新的 TreeView
實例,它將舊 MyControllerClass
實例的locationTreeView
成員設置為。 我更新了您的代碼以進行上面建議的修改,現在代碼可以正常工作。 更新的代碼可用 。
運行代碼的示例屏幕截圖如下:
MyApplicationClass.java
import javafx.animation.*;
import javafx.application.Application;
import javafx.event.*;
import javafx.fxml.FXMLLoader;
import javafx.scene.*;
import javafx.scene.image.Image;
import javafx.scene.input.MouseEvent;
import javafx.stage.*;
import javafx.util.Duration;
/** Sample application to demonstrate programming an FXML interface. */
public class MyApplicationClass extends Application {
@Override public void start(final Stage stage) throws Exception {
// load the scene fxml UI.
// grabs the UI scenegraph view from the loader.
// grabs the UI controller for the view from the loader.
final FXMLLoader loader = new FXMLLoader(getClass().getResource("myInterface.fxml"));
final Parent root = (Parent) loader.load();
final MyControllerClass controller = loader.<MyControllerClass>getController();
// continuously refresh the TreeItems.
// demonstrates using controller methods to manipulate the controlled UI.
final Timeline timeline = new Timeline(
new KeyFrame(
Duration.seconds(3),
new TreeLoadingEventHandler(controller)
)
);
timeline.setCycleCount(Timeline.INDEFINITE);
timeline.play();
// close the app if the user clicks on anywhere on the window.
// just provides a simple way to kill the demo app.
root.addEventFilter(MouseEvent.MOUSE_CLICKED, new EventHandler<MouseEvent>() {
@Override public void handle(MouseEvent t) {
stage.hide();
}
});
// initialize the stage.
stage.setScene(new Scene(root));
stage.initStyle(StageStyle.TRANSPARENT);
stage.getIcons().add(new Image(getClass().getResourceAsStream("myIcon.png")));
stage.show();
}
/** small helper class for handling tree loading events. */
private class TreeLoadingEventHandler implements EventHandler<ActionEvent> {
private MyControllerClass controller;
private int idx = 0;
TreeLoadingEventHandler(MyControllerClass controller) {
this.controller = controller;
}
@Override public void handle(ActionEvent t) {
controller.loadTreeItems("Loaded " + idx, "Loaded " + (idx + 1), "Loaded " + (idx + 2));
idx += 3;
}
}
// main method is only for legacy support - java 8 won't call it for a javafx application.
public static void main(String[] args) { launch(args); }
}
MyControllerClass.java
import javafx.fxml.FXML;
import javafx.scene.control.*;
/** Sample controller class. */
public class MyControllerClass {
// the FXML annotation tells the loader to inject this variable before invoking initialize.
@FXML private TreeView<String> locationTreeView;
// the initialize method is automatically invoked by the FXMLLoader - it's magic
public void initialize() {
loadTreeItems("initial 1", "initial 2", "initial 3");
}
// loads some strings into the tree in the application UI.
public void loadTreeItems(String... rootItems) {
TreeItem<String> root = new TreeItem<String>("Root Node");
root.setExpanded(true);
for (String itemString: rootItems) {
root.getChildren().add(new TreeItem<String>(itemString));
}
locationTreeView.setRoot(root);
}
}
myInterface.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" xmlns:fx="http://javafx.com/fxml" fx:controller="test.MyControllerClass">
<TreeView fx:id="locationTreeView" layoutX="0" layoutY="0" prefHeight="193.0" prefWidth="471.0" />
</AnchorPane>
在loadTreeItems()函數中,您將創建一個新的TreeView實例。 這將替換FXML文件中定義的並使用不屬於場景圖的新實例附加到場景的那個。
要將項添加到通過FXMLLoader創建的TreeView,您可以使用setRoot()函數。
private void loadTreeItems() {
try {
TreeItem<String> root = new TreeItem<String>("Root Node");
root.setExpanded(true);
root.getChildren().addAll(
new TreeItem<String>("Item 1"),
new TreeItem<String>("Item 2"),
new TreeItem<String>("Item 3")
);
locationTreeView.setRoot(root);
} catch (Exception exc) {
System.out.println("Error: " + exc.getMessage());
}
}
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