Question

我有一个问题是什么部分解决了，但我很好奇另一个（更好的）解决方案.. 我想要一个填充整个窗口的画布，并在调整窗口大小时自行调整大小。

选项1（部分解决方案）：

据此：https://dlemmermann.wordpress.com/2014/04/10/javafx-tip-1-resizable-canvas/ 而这：How to make canvas Resizable in javaFX? 我创建（复制）了这个类：

public class ResizableCanvas extends Canvas {

    public ResizableCanvas() {
        widthProperty().addListener(evt -> draw());
        heightProperty().addListener(evt -> draw());
    }

    private void draw() {
        double width = getWidth();
        double height = getHeight();

        GraphicsContext gc = getGraphicsContext2D();
        gc.clearRect(0, 0, width, height);

        gc.setStroke(Color.RED);
        gc.strokeLine(0, 0, width, height);
        gc.strokeLine(0, height, width, 0);
    }

    @Override
    public boolean isResizable() {
        return true;
    }

    @Override
    public double prefWidth(double height) {
        return getWidth();
    }

    @Override
    public double prefHeight(double width) {
        return getHeight();
    }
}

我将以下内容放入我的ViewField.fxml文件中：

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

<?import javafx.scene.canvas.Canvas?>
<?import javafx.scene.layout.StackPane?>
<?import blahblahblah.ResizableCanvas?>

<StackPane fx:id="pane" minHeight="500.0" minWidth="500.0" style="-fx-background-color: white; -fx-border-color: black;" xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1" fx:controller="blahblahblah.ViewFieldController">
   <children>
      <ResizableCanvas fx:id="resizableCanvas" />
   </children>
</StackPane>

我的控制器（附加到此fxml文件）是ViewFieldController.java：

import javafx.beans.property.ReadOnlyDoubleProperty;
import javafx.fxml.FXML;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class ViewFieldController {

    private Stage dialogStage;

    @FXML
    private StackPane pane;

    @FXML
    private ResizableCanvas resizableCanvas;

    @FXML
    private void initialize() {

        GraphicsContext gc = resizableCanvas.getGraphicsContext2D();

        ReadOnlyDoubleProperty widthProperty = pane.widthProperty();
        ReadOnlyDoubleProperty heightProperty = pane.heightProperty();
        resizableCanvas.widthProperty().bind(widthProperty);
        resizableCanvas.heightProperty().bind(heightProperty);

        drawArea(gc);
    }

    public void setDialogStage(Stage dialogStage) {
        this.dialogStage = dialogStage;
    }

    private void drawArea(GraphicsContext gc) {

        gc.setStroke(Color.BLACK);
        gc.setLineWidth(1);
        gc.strokeLine(0, 0, resizableCanvas.getWidth(), resizableCanvas.getHeight());
        gc.strokeLine(0, resizableCanvas.getHeight(), resizableCanvas.getWidth(), 0);
    }

}

从主控制器MainApp.java加载窗口：

public class MainApp extends Application {

public static void main(String[] args) {
    launch(args);
}
//...

public void showViewField() {
    try {
        FXMLLoader loader = new FXMLLoader();
        loader.setLocation(MainApp.class.getResource("view/ViewField.fxml"));
        StackPane pane = (StackPane) loader.load();

        Stage stage = new Stage();
        stage.setTitle("View Field");
        Scene scene = new Scene(pane);
        stage.setScene(scene);

        ViewFieldController controller = loader.getController();
        controller.setDialogStage(stage);

        stage.show();

    } catch (IOException e) {
        e.printStackTrace();
    }
}

}

此解决方案有效（由于drawArea（）方法，画布上出现“big X”）。这个解决方案的问题是，在将ResisableCanvas类放入FXML文件之后，我无法在此文件上使用SceneBuilder，因为我得到以下异常：

java.io.IOException: javafx.fxml.LoadException: 
...

    at com.oracle.javafx.scenebuilder.kit.fxom.FXOMLoader.load(FXOMLoader.java:92)
    at com.oracle.javafx.scenebuilder.kit.fxom.FXOMDocument.<init>(FXOMDocument.java:82)
    at com.oracle.javafx.scenebuilder.kit.fxom.FXOMDocument.<init>(FXOMDocument.java:97)
    at com.oracle.javafx.scenebuilder.kit.editor.EditorController.updateFxomDocument(EditorController.java:2384)
    at com.oracle.javafx.scenebuilder.kit.editor.EditorController.setFxmlTextAndLocation(EditorController.java:664)
    at com.oracle.javafx.scenebuilder.app.DocumentWindowController.loadFromFile(DocumentWindowController.java:381)
    at com.oracle.javafx.scenebuilder.app.SceneBuilderApp.performOpenFiles(SceneBuilderApp.java:554)
    at com.oracle.javafx.scenebuilder.app.SceneBuilderApp.handleOpenFilesAction(SceneBuilderApp.java:424)
    at com.oracle.javafx.scenebuilder.app.SceneBuilderApp.handleLaunch(SceneBuilderApp.java:403)
    at com.oracle.javafx.scenebuilder.app.AppPlatform.requestStartGeneric(AppPlatform.java:139)
    at com.oracle.javafx.scenebuilder.app.AppPlatform.requestStart(AppPlatform.java:106)
    at com.oracle.javafx.scenebuilder.app.SceneBuilderApp.start(SceneBuilderApp.java:353)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$163(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$176(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$174(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$175(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$149(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)
Caused by: javafx.fxml.LoadException: 
...

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
    at javafx.fxml.FXMLLoader.importClass(FXMLLoader.java:2848)
    at javafx.fxml.FXMLLoader.processImport(FXMLLoader.java:2692)
    at javafx.fxml.FXMLLoader.processProcessingInstruction(FXMLLoader.java:2661)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2517)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2425)
    at com.oracle.javafx.scenebuilder.kit.fxom.FXOMLoader.load(FXOMLoader.java:89)
    ... 20 more
Caused by: java.lang.ClassNotFoundException: blahblahblah.ResizableCanvas
    at java.lang.ClassLoader.findClass(ClassLoader.java:530)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at javafx.fxml.FXMLLoader.loadTypeForPackage(FXMLLoader.java:2916)
    at javafx.fxml.FXMLLoader.loadType(FXMLLoader.java:2905)
    at javafx.fxml.FXMLLoader.importClass(FXMLLoader.java:2846)
    ... 25 more

选项2（部分解决方案）：

我的第二个解决方案使用相同的ResizableCanvas类，但没有FXML文件或控制器类。

public class MainApp extends Application {

    //...

    public void showViewField2() {

        ResizableCanvas canvas = new ResizableCanvas();
        StackPane pane = new StackPane();
        pane.getChildren().add(canvas);

        Stage stage = new Stage();
        stage.setTitle("View Field");
        Scene scene = new Scene(pane);
        stage.setScene(scene);

        canvas.widthProperty().bind(pane.widthProperty());
        canvas.heightProperty().bind(pane.heightProperty());

        stage.show();
    }

}

此解决方案也有效（屏幕上出现大X），但此处出现同样的问题：我无法在ScreenBuilder中打开FXML文件，但出于不同的原因（根本没有FXML文件）。

选项3（我的原始解决方案，无效）：

我已使用原始Canvas类替换了ViewField.fxml文件中的ResizableCanvas类：

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

<?import javafx.scene.canvas.Canvas?>
<?import javafx.scene.layout.StackPane?>

<StackPane fx:id="pane"  minHeight="500.0" minWidth="500.0" style="-fx-background-color: white; -fx-border-color: black;" xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1" fx:controller="blahblahblah.ViewFieldController">
   <children>
      <Canvas fx:id="regularCanvas" />
   </children>
</StackPane>

我的ViewFieldController.java如下所示：

import javafx.beans.property.ReadOnlyDoubleProperty;
import javafx.fxml.FXML;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

public class ViewFieldController {

    private Stage dialogStage;

    @FXML
    private StackPane pane;

    @FXML
    private Canvas regularCanvas;

    @FXML
    private void initialize() {

        GraphicsContext gc = regularCanvas.getGraphicsContext2D();

        ReadOnlyDoubleProperty widthProperty = pane.widthProperty();
        ReadOnlyDoubleProperty heightProperty = pane.heightProperty();
        regularCanvas.widthProperty().bind(widthProperty);
        regularCanvas.heightProperty().bind(heightProperty);

        drawArea(gc);
    }

    public void setDialogStage(Stage dialogStage) {
        this.dialogStage = dialogStage;
    }

    private void drawArea(GraphicsContext gc) {

        gc.setStroke(Color.BLACK);
        gc.setLineWidth(1);
        gc.strokeLine(0, 0, regularCanvas.getWidth(), regularCanvas.getHeight());
        gc.strokeLine(0, regularCanvas.getHeight(), regularCanvas.getWidth(), 0);
    }

}

但是这里的屏幕是空的。画布上没有“大X”。如果我调整窗口大小，我不知道画布是否调整大小，但是可以将FXML文件加载到SceneBuilder中以进行进一步的工作。

如果我给画布一些高度和宽度并不是更好（结果是相同的）。

<StackPane fx:id="pane" minHeight="500.0" minWidth="500.0" style="-fx-background-color: white; -fx-border-color: black;" xmlns="http://javafx.com/javafx/8.0.65" xmlns:fx="http://javafx.com/fxml/1" fx:controller="blahblahblah.ViewFieldController">
   <children>
      <Canvas fx:id="regularCanvas" height="300.0" width="300.0" />
   </children>
</StackPane>

我的问题是：

为什么第三种情况下没有出现“大X”？
我应该做些什么修改才能使第3个案例有效？
有什么其他解决方案可以解决我的问题吗？
为什么我在第一种情况下得到例外？
为什么在SceneBuilder中“适合父级”画布是不可能的？
为什么在SceneBuilder中禁用“可抵抗”选项？

Answer 1

您可以通过将自定义画布捆绑到jar文件并将其导入Scene Builder库，使选项1与Scene Builder一起使用。例如，请参阅this question。

选项3不起作用，因为您只从drawArea()方法调用initialize()。此时，画布不是Scene的一部分，当然也不会显示在窗口中;因此没有经历布局，所以没有宽度和高度。您可以通过向宽度和高度添加侦听器并在更改时重新绘制来修复此选项，如同在选项1中所做的那样：

@FXML
private void initialize() {

    GraphicsContext gc = regularCanvas.getGraphicsContext2D();

    ReadOnlyDoubleProperty widthProperty = pane.widthProperty();
    ReadOnlyDoubleProperty heightProperty = pane.heightProperty();
    regularCanvas.widthProperty().bind(widthProperty);
    regularCanvas.heightProperty().bind(heightProperty);

    regularCanvas.widthProperty().addListener((obs, oldWidth, newWidth) -> drawArea(gc));
    regularCanvas.heightProperty().addListener((obs, oldHeight, newHeight) -> drawArea(gc));

    drawArea(gc);
}

JavaFX可调整大小的画布问题

1 个答案: