加载另一个 FXML 文件后，透明舞台/场景失去透明度

Question

当我启动我的应用程序时，我的透明javafx.stage.Stage 按预期显示半透明图像。但是在加载第二阶段后，第一阶段就失去了透明度。

奇怪的是，如果第二个 fxml 文件（“MainScreen.fxml”）不包含按钮或文本字段等任何组件，则背景保持透明。

我在 macOS Sierra 上的 eclipse neon.2 中使用 JavaFX 和 JavaSE-1.8。

主类

package customPackage.main;

import javafx.animation.FadeTransition;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Rectangle2D;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.stage.Screen;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
import javafx.util.Duration;

public class Main extends Application implements Runnable {

    private Stage primaryStage;
    private Stage stage;

    private Controller launchController;

    @Override
    public void start(Stage primaryStage) {
        this.primaryStage = primaryStage;

        launchController = new Controller("LaunchScreen.fxml");
        Scene launchScene = new Scene(launchController);

        launchScene.setFill(Color.TRANSPARENT);

        primaryStage.initStyle(StageStyle.TRANSPARENT);
        primaryStage.setAlwaysOnTop(true);
        primaryStage.setResizable(false);
        primaryStage.setScene(launchScene);
        primaryStage.show();

        Thread thread = new Thread(this);
        thread.start();
    }

    @Override
    public void run() {
        try {
            Thread.sleep(3000);
            // simulate work
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Controller controller = new Controller("MainScreen.fxml");
        Scene scene = new Scene(controller);

        Platform.runLater(new Runnable() {
            @Override
            public void run() {
                stage = new Stage();
                stage.initStyle(StageStyle.UNDECORATED);
                stage.setResizable(false);
                stage.setScene(scene);
                stage.show();
            }
        });
    }
}

控制器类

package customPackage.main;

import java.io.IOException;

import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.AnchorPane;

public class LaunchController extends AnchorPane {

    @FXML
    private ProgressBar bar;

    public LaunchController(String filename) {
        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource(filename));
        fxmlLoader.setRoot(this);
        fxmlLoader.setController(this);

        try {
            fxmlLoader.load();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

FXML 文件（“LaunchScreen.fxml”）

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

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

<fx:root fx:id="pane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="326.0" prefWidth="883.0" type="AnchorPane" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <ImageView fitHeight="326.0" fitWidth="883.0" layoutX="7.0" layoutY="134.0" pickOnBounds="true" preserveRatio="true" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
         <image>
            <Image url="@http://www.lunapic.com/editor/premade/transparent.gif" />
         </image>
      </ImageView>
   </children>
   <cursor>
      <Cursor fx:constant="DEFAULT" />
   </cursor>
</fx:root>

FXML 文件（“MainScreen.fxml”）

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

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

<fx:root fx:id="pane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="720.0" prefWidth="1280.0" type="AnchorPane" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <ImageView fitHeight="720.0" fitWidth="1280.0" pickOnBounds="true" preserveRatio="true" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
         <image>
            <Image url="@http://i.telegraph.co.uk/multimedia/archive/03589/Wellcome_Image_Awa_3589699k.jpg" />
         </image>
      </ImageView>
      <HBox spacing="100.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0">
         <children>
            <Button fx:id="button1" mnemonicParsing="false" onAction="#button1Press" prefHeight="45.0" prefWidth="1000.0" text="Singleplayer" />
            <Button fx:id="button2" mnemonicParsing="false" onAction="#button2Press" prefHeight="45.0" prefWidth="1000.0" text="Multiplayer" />
            <Button fx:id="button3" mnemonicParsing="false" onAction="#button3Press" prefHeight="45.0" prefWidth="1000.0" text="Settings" />
            <Button fx:id="button4" mnemonicParsing="false" onAction="#button4Press" prefHeight="45.0" prefWidth="1000.0" text="Quit" />
         </children>
         <padding>
            <Insets bottom="30.0" left="100.0" right="100.0" top="20.0" />
         </padding>
      </HBox>
      <Region fx:id="region" prefHeight="15.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0" />
   </children>
</fx:root>

解决方案（由 James_D 解决）

我加了

.root {
    -fx-background-color: transparent;
}

添加到外部样式表并将stylesheets="@application.css" 添加到 FXML 文件的根节点。

Answer 1

JavaFX 的默认 CSS 样式表 modena 将非透明颜色应用于根节点的背景。这是您在显示主视图时看到的颜色。

您在第一个屏幕中看不到这个的原因，或者如果您从主屏幕中删除按钮，是因为默认样式表仅在第一次加载 Control 类（或其一个子类）时) 被实例化。这样做是为了避免不需要它的应用程序的 CSS 处理开销。

要修复，要么将style="-fx-background-color: transparent;"添加到FXML文件的根节点，要么添加规则

.root {
    -fx-background-color: transparent ;
}

到外部样式表。