多くの有用な記事は正当化されていないように思われます。JavaFXの使用を開始するときに最も熱心な質問にいくつかの言葉を捧げないだけでなく、それらを捧げたとしても、まだ完全には開示していません。そして、次のように疑問が生じます。fx:idとコードによってノードを通信する方法。APIを参照するために、コードのさまざまな部分でそれらをどのように使用しますか?これは私がカットの下で答えようとするものです
fxとは何ですか:idとそれが食べられるもの
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, "hello world":
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.Pane?>
<?import javafx.scene.control.Button?>
<Pane xmlns="http://javafx.com/javafx/1.8.0.261" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Main">
<Button fx:id="fxButton" text="clickMe" onAction="#click"/>
</Pane>
public class Main extends Application {
@FXML
public Button fxButton;
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("YourFXML.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
public void click(ActionEvent actionEvent) {
System.out.println("Hello World");
fxButton.setText("Hey!");
}
}
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public class Main extends Application {
@FXML
public Button fxButton;
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("YourFXML.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
// , ( ):
fxButton.addEventHandler(MouseEvent.MOUSE_CLICKED, mouseEvent -> System.out.println("Hello World"));
}
}
IDE
Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
at sample.Main.start(Main.java:25)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
… 1 more
Exception running application sample.Main
Process finished with exit code 1
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FXML. .
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<Pane xmlns="http://javafx.com/javafx/1.8.261" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Controller">
<VBox layoutX="14.0" prefHeight="50.0" prefWidth="50.0">
<Button fx:id="fxButton" onAction="#click" text="clickMe" />
<Label fx:id="labelFx" minHeight="17.0" minWidth="185.0" text="label" />
</VBox>
</Pane>
Main. , , FXML
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("YourFXML.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
Controller. FXML java .
public class Controller extends View implements Initializable {
@FXML
private Button fxButton;
@FXML
private Label labelFx;
@FXML
Label localLabel;
@FXML
public void click(ActionEvent actionEvent) {
System.out.println("Hello World");
fxButton.setText("Hey!");
labelLocalInitialize();
}
private void labelLocalInitialize(){
localLabel = labelFx;
localLabel.setText("local variable control");
}
@Override
public void initialize(URL location, ResourceBundle resources) {
// View labelFx
setViewLabelFxText("transfer of control in View \"labelFx\" variable");
// , ,
fxButton.addEventHandler(MouseEvent.MOUSE_CLICKED, mouseEvent -> System.out.println("Listener triggered"));
}
}
View. , .
public class View {
@FXML
private Label labelFx;
public void setViewLabelFxText(String text){
labelFx.setText(text);
}
}
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FXML .
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"Hello World", "Hey!", labelLocalInitialize(), labelFx. , labelFx .
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上記のどこかで、javaFXには魔法があると言いました。Viewクラスから始まります。コントローラからクラスを継承してidを操作することが可能かどうかは明らかなようですが、逆のことが起こります...なぜこれが行われるのか、詳細には触れませんでしたが、なぜそうなるのか興味があります。コメントで知識のある人が秘密のベールを開けたら、私はとても感謝します。