SplitPane布局问题

Question

这是一个交叉的帖子：http://mail.openjdk.java.net/pipermail/openjfx-dev/2015-January/016437.html

有时，当我以编程方式设置SplitPane的分隔符位置时，我的值再次被一些JavaFX内部布局代码覆盖。

为了调试目的，我向分隔符的position属性添加了一个侦听器，并抛出了一个RuntimeException来查看堆栈跟踪。看起来是这样的：

at 
com.sun.javafx.binding.ExpressionHelper$Generic.fireValueChangedEvent(ExpressionHelper.java:361)
        at 
com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:81)
        at 
javafx.beans.property.DoublePropertyBase.fireValueChangedEvent(DoublePropertyBase.java:106)
        at 
javafx.beans.property.DoublePropertyBase.markInvalid(DoublePropertyBase.java:113)
        at 
javafx.beans.property.DoublePropertyBase.set(DoublePropertyBase.java:146)
        at javafx.scene.control.SplitPane$Divider.setPosition(SplitPane.java:486)
        at 
com.sun.javafx.scene.control.skin.SplitPaneSkin.setAbsoluteDividerPos(SplitPaneSkin.java:310)
        at 
com.sun.javafx.scene.control.skin.SplitPaneSkin.setupContentAndDividerForLayout(SplitPaneSkin.java:502)
        at 
com.sun.javafx.scene.control.skin.SplitPaneSkin.layoutChildren(SplitPaneSkin.java:817)
        at javafx.scene.control.Control.layoutChildren(Control.java:589)
        at javafx.scene.Parent.layout(Parent.java:1074)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Parent.layout(Parent.java:1080)
        at javafx.scene.Scene.doLayoutPass(Scene.java:532)
        at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2363)
        at com.sun.javafx.tk.Toolkit.lambda$runPulse$28(Toolkit.java:314)
        at com.sun.javafx.tk.Toolkit$$Lambda$230/25595560.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:313)
        at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:340)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:451)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:431)
        at 
com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$363(QuantumToolkit.java:298)
        at 
com.sun.javafx.tk.quantum.QuantumToolkit$$Lambda$59/174792896.run(Unknown 
Source)
        at 
com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
        at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
        at 
com.sun.glass.ui.gtk.GtkApplication.lambda$null$45(GtkApplication.java:126)
        at com.sun.glass.ui.gtk.GtkApplication$$Lambda$55/1472148546.run(Unknown 
Source)
        at java.lang.Thread.run(Thread.java:745)

它似乎不会被我的代码触发(至少不会直接根据堆栈跟踪)。

我尝试了几种方法，包括将项目的prefWidth/ prefHeight设置为期望值，但我无法阻止SplitPane在重新布局期间有效地“隐藏”第一个和第三个(最后)项。

在layoutChildren调用期间，这两个分隔符更改如下：

分隔符位置更改:旧值: 0.10857763300760044，新值: 0.004343105320304018

分隔符位置更改:旧值: 0.8914223669923995，新值: 0.995656894679696

我看了一下com.sun.javafx.scene.control.skin.SplitPaneSkin (JDK提供的源代码)，但不幸的是，在这种情况下很难看到这些区域是如何计算的。

为什么这里会发生新的布局？为什么它要覆盖我为分隔符位置设置的值？怎么才能阻止这一切？

我尝试过编写一个SSCCE，但是我还不能用一个简单的示例来重现这个问题。(此问题发生在自定义控件的皮肤实现中。)

更新

所讨论的SplitPane的三个项(控件的子类)(方向:垂直)具有以下最小和最大高度：

property: height min: -1.0 ; max: -1.0
property: height min: -1.0 ; max: -1.0
property: height min: -1.0 ; max: -1.0

这是大小的值。

我将最大值更改为Double.MAX_VALUE

property: height min: -1.0 ; max: 1.7976931348623157E308 
property: height min: -1.0 ; max: 1.7976931348623157E308 
property: height min: -1.0 ; max: 1.7976931348623157E308

但我还是遇到了同样的问题。

更新2

我终于成功地创建了一个SSCCE：

package splitpanelayoutissue;

import javafx.application.Application;
import javafx.geometry.Orientation;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.SplitPane;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class SplitPaneLayoutIssue extends Application {

    private static final double DIVIDER_POSITION_0 = 0.10834236186348863;
    private static final double DIVIDER_POSITION_1 = 0.8916576381365114;

    @Override
    public void start(Stage primaryStage) {
        SplitPane outerSplitPane = createOuterSplitPane();

        StackPane root = new StackPane();
        root.getChildren().add(outerSplitPane);

        Scene scene = new Scene(root, 1500, 1000);

        primaryStage.setTitle("SplitPane Layout Issue");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private SplitPane createOuterSplitPane() {
        SplitPane outerSplitPane = createSplitPane("outerSplitPane");

        TabPane leftTabPane = addTabPane(outerSplitPane, "Left");

        SplitPane innerSplitPane = createInnerSplitPane();
        outerSplitPane.getItems().add(innerSplitPane);

        TabPane rightTabPane = addTabPane(outerSplitPane, "Right");

        SplitPane.setResizableWithParent(leftTabPane, Boolean.FALSE);
        SplitPane.setResizableWithParent(rightTabPane, Boolean.FALSE);
        SplitPane.setResizableWithParent(innerSplitPane, Boolean.TRUE);

        setDividerPositions(outerSplitPane, innerSplitPane);

        leftTabPane.getTabs().get(0).setOnClosed(event -> {
            // the following line causes com.sun.javafx.scene.control.skin.SplitPaneSkin.Content.getArea() 
            // of all 3 items return 0, even though setDividerPositions is called before the next SplitPane.layoutChildren call
            innerSplitPane.getItems().setAll(innerSplitPane.getItems().get(0),innerSplitPane.getItems().get(1),innerSplitPane.getItems().get(2));

            outerSplitPane.getItems().setAll(innerSplitPane, rightTabPane);
            setDividerPositions(outerSplitPane, innerSplitPane);
        });

        return outerSplitPane;
    }

    private SplitPane createSplitPane(String name) {
        SplitPane splitPane = new SplitPane() {

            @Override
            protected void layoutChildren() {
                System.out.println("Calling relayout on " + name + "...");
                com.sun.javafx.scene.control.skin.SplitPaneSkin skin = (com.sun.javafx.scene.control.skin.SplitPaneSkin) getSkin();
                super.layoutChildren();
            }

        };
        return splitPane;
    }

    private void setDividerPositions(SplitPane outerSplitPane, SplitPane innerSplitPane) {
        System.out.println("Set divider positions...");
        System.out.println("Set divider position 0 of outerSplitPane...");
        outerSplitPane.setDividerPosition(0, outerSplitPane.getItems().size() == 3 ? DIVIDER_POSITION_0
                : DIVIDER_POSITION_1);
        if (outerSplitPane.getItems().size() == 3) {
            System.out.println("Set divider position 1 of outerSplitPane...");
            outerSplitPane.setDividerPosition(1, DIVIDER_POSITION_1);
        }
        System.out.println("Set divider position 0 of innerSplitPane...");
        innerSplitPane.setDividerPosition(0, DIVIDER_POSITION_0);
        System.out.println("Set divider position 1 of innerSplitPane...");
        innerSplitPane.setDividerPosition(1, DIVIDER_POSITION_1);
    }

    private TabPane addTabPane(SplitPane splitPane, String label) {
        TabPane tabPane = new TabPane();
//        tabPane.setFocusTraversable(false);
        Tab tab = new Tab(label);
        tab.setContent(new Label(label));
        tabPane.getTabs().add(tab);
        splitPane.getItems().add(tabPane);
        return tabPane;
    }

    private SplitPane createInnerSplitPane() {
        SplitPane innerSplitPane = createSplitPane("innerSplitPane");
        innerSplitPane.setOrientation(Orientation.VERTICAL);

        TabPane topTabPane = addTabPane(innerSplitPane, "Top");
        TabPane centerTabPane = addTabPane(innerSplitPane, "Center");
        TabPane bottomTabPane = addTabPane(innerSplitPane, "Bottom");

        SplitPane.setResizableWithParent(topTabPane, Boolean.FALSE);
        SplitPane.setResizableWithParent(bottomTabPane, Boolean.FALSE);

        SplitPane.setResizableWithParent(centerTabPane, Boolean.TRUE);

        return innerSplitPane;
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

如果关闭左侧选项卡，则顶部和底部选项卡将被隐藏(大小为0)，尽管分隔符位置是在layoutChildren()调用之前设置的(请参见输出)。

我之所以会遇到这种情况，是因为我需要在代码中重置splitPane的项。还请注意，这些项具有不同的resizableWithParent属性。

更新3

下面是一个较小的SSCCE，它只有一个SplitPane。当你按下“增长宽度”按钮时，你会看到同样的效果。

package splitpanelayoutissue;

import javafx.application.Application;
import javafx.geometry.Orientation;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.SplitPane;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;

public class SplitPaneLayoutIssue2 extends Application {

    private static final double DIVIDER_POSITION_0 = 0.10834236186348863;
    private static final double DIVIDER_POSITION_1 = 0.8916576381365114;

    @Override
    public void start(Stage primaryStage) {
        SplitPane splitPane = createSplitPane();

        StackPane root = new StackPane();
        root.getChildren().add(splitPane);

        Scene scene = new Scene(root, 1500, 1000);

        primaryStage.setTitle("SplitPane Layout Issue");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private SplitPane createSplitPane(String name) {
        SplitPane splitPane = new SplitPane() {

            @Override
            protected void layoutChildren() {
                System.out.println("Calling relayout on " + name + "...");
                com.sun.javafx.scene.control.skin.SplitPaneSkin skin = (com.sun.javafx.scene.control.skin.SplitPaneSkin) getSkin();
                super.layoutChildren();
            }

        };
        return splitPane;
    }

    private void setDividerPositions(SplitPane innerSplitPane) {
        System.out.println("Set divider positions...");
        System.out.println("Set divider position 0 of innerSplitPane...");
        innerSplitPane.setDividerPosition(0, DIVIDER_POSITION_0);
        System.out.println("Set divider position 1 of innerSplitPane...");
        innerSplitPane.setDividerPosition(1, DIVIDER_POSITION_1);
    }

    private TabPane addTabPane(SplitPane splitPane, String label) {
        TabPane tabPane = new TabPane();
//        tabPane.setFocusTraversable(false);
        Tab tab = new Tab(label);
        tab.setContent(new Label(label));
        tabPane.getTabs().add(tab);
        splitPane.getItems().add(tabPane);
        return tabPane;
    }

    private SplitPane createSplitPane() {
        SplitPane splitPane = createSplitPane("splitPane");
        splitPane.setOrientation(Orientation.VERTICAL);

        TabPane topTabPane = addTabPane(splitPane, "Top");

        TabPane centerTabPane = new TabPane();
//        tabPane.setFocusTraversable(false);
        Tab tab = new Tab("Center");
        Button button = new Button("Grow width");
        tab.setContent(button);
        button.setOnAction(event -> {
            System.out.println("Growing window width...");
            // the following line causes com.sun.javafx.scene.control.skin.SplitPaneSkin.Content.getArea() 
            // of all 3 items return 0, even though setDividerPositions is called before the next SplitPane.layoutChildren call
            // Without this line the code works fine.
            splitPane.getItems().setAll(splitPane.getItems().get(0), splitPane.getItems().get(1), splitPane.getItems().get(2));

            // This line is needed to trigger the execution path in question
            splitPane.getScene().getWindow().setWidth(splitPane.getScene().getWindow().getWidth() + 20.0);
            setDividerPositions(splitPane);
        });
        centerTabPane.getTabs().add(tab);

        splitPane.getItems().add(centerTabPane);

        TabPane bottomTabPane = addTabPane(splitPane, "Bottom");

        setDividerPositions(splitPane);
        SplitPane.setResizableWithParent(topTabPane, Boolean.FALSE);
        SplitPane.setResizableWithParent(bottomTabPane, Boolean.FALSE);

        SplitPane.setResizableWithParent(centerTabPane, Boolean.TRUE);

        return splitPane;
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

这是一个JavaFX错误，还是某种我可以影响的东西？

Answer 1

由于这似乎是一个JavaFX问题，我在这里提交了一个问题：https://javafx-jira.kenai.com/browse/RT-40031

更新：

这个问题可以复制，但已经在即将发布的JavaFX 8u40中修复。

Answer 2

我认为堆栈跟踪的重要部分是：

com.sun.javafx.scene.control.skin.SplitPaneSkin.setAbsoluteDividerPos(SplitPaneSkin.java:310) at com.sun.javafx.scene.control.skin.SplitPaneSkin.setupContentAndDividerForLayout(SplitPaneSkin.java:502) at com.sun.javafx.scene.control.skin.SplitPaneSkin.layoutChildren(SplitPaneSkin.java:817)

如您所见，JavaFX默认布局机制(layoutChildren())是为SplitPane实现的，其方式可能会影响分隔符的位置。setupContentAndDividerForLayout()方法在layoutChildren()方法中的某些内部if语句中被调用。因此，我将调试这个方法，并检查为什么调用setupContentAndDividerForLayout()。通过这样做，您可以找到为什么SplitPane认为它必须改变除法器的位置。

Answer 3

这似乎是最近在JavaFX中引入的东西。我用Java8u20 (b26)和Java8u40ea(早期采用者) (b23)在Windows 7上测试了这一点。

使用您的SSCCE，我可以看到在Java 8u20中，如果我将窗口的高度调整为较小，然后单击Grow，则上、下选项卡的高度与以前相同。

如果我在Java8u40ea中做同样的事情，那么当我调整窗口的大小时，上面和下面的选项卡会得到自己的高度调整为更小，然后单击按钮。如果我再次调整窗口的大小以使其更高，则当我单击按钮时，选项卡再次调整大小为大(与以前一样)。

听起来像是要和JavaFX的家伙一起打开；几天前，我亲自提交了一个SSCCE，他们非常有反应。