JavaFX Glitches 动画非标准小部件

Question

我正在尝试使用 JavaFX 证明可扩展小部件与 TitledPane 的不同之处在于标签周围的边框随着小部件的扩展而增长。我找到了一种方法。

但是我有一个奇怪的故障，在 expanding/collapsing 之后出现一两次。

这是一个link的短视频，问题出现在第三次和第四次展开：

我已经没有什么可以尝试让它正常运行的东西了。

代码如下，对它的古怪表示歉意，我想在重构它之前让它工作。

class ExpansionManager {
    enum LayoutState {
        INITIALIZE,
        ANIMATING,
        IDLE,
        REQUEST_ANIMATION
    }

    LayoutState layoutState = LayoutState.INITIALIZE;
    Double fromWidth = 0.0;
    Double fromHeight = 0.0;
    Double stepWidth = 0.0;
    Double stepHeight = 0.0;
    Double toWidth = 0.0;
    Double toHeight = 0.0;
}

public class ExpandableTitledList extends VBox {
    private Label title = new Label();
    private ListProperty<String> listItem = new SimpleListProperty<>();
    private ListView listView = new ListView<>(listItem);
    Timeline timeline;

    WritableValue<Double> writableHeight = new WritableValue<Double>() {
        @Override
        public Double getValue() {
            return expansionManager.stepHeight;
        }

        @Override
        public void setValue(Double value) {
            expansionManager.stepHeight = value;
            requestLayout();
        }
    };

    WritableValue<Double> writableWidth = new WritableValue<Double>() {
        @Override
        public Double getValue() {
            return expansionManager.stepWidth;
        }

        @Override
        public void setValue(Double value) {
            expansionManager.stepWidth = value;
            requestLayout();
        }
    };

    private boolean expanded = false;
    ExpansionManager expansionManager = new ExpansionManager();
//    private Dimension2D contractedDimension;
//    private Dimension2D expandedDimension;


    public ExpandableTitledList() {
        setTitle("boom");
//        title.layout();
//        System.out.println(title.getLayoutBounds().getWidth());
        // set down right caret
        listItem.setValue(FXCollections.observableArrayList("one", "two"));

        Insets theInsets = new Insets(-3, -5, -3, -5);
        Border theBorder = new Border(
                new BorderStroke(
                        Color.BLACK,
                        BorderStrokeStyle.SOLID,
                        new CornerRadii(4),
                        new BorderWidths(2),
                        theInsets
                )
        );

//        expandedDimension = new Dimension2D(200,200);

        setBorder(theBorder);
        getChildren().addAll(title);

        title.setOnMouseClicked((event) -> {
            System.out.println("mouse clicked");
            if (this.expanded) contract();
            else expand();
        });
    }

    @Override
    protected void layoutChildren() {
        System.out.println(expansionManager.layoutState);
        if (expansionManager.layoutState == ExpansionManager.LayoutState.INITIALIZE) {
            super.layoutChildren();
            expansionManager.layoutState = ExpansionManager.LayoutState.IDLE;
        } else if (expansionManager.layoutState == ExpansionManager.LayoutState.ANIMATING) {
            super.layoutChildren();
        } else if (expansionManager.layoutState == ExpansionManager.LayoutState.REQUEST_ANIMATION) {
            setCache(false);
            listView.setCache(false);

            expansionManager.layoutState = ExpansionManager.LayoutState.ANIMATING;
            System.out.println("from : " + expansionManager.fromWidth + ", "+ expansionManager.fromHeight);
            System.out.println("to : " + expansionManager.toWidth + ", "+ expansionManager.toHeight);

            timeline = new Timeline();

            timeline.getKeyFrames().addAll(
                    new KeyFrame(Duration.ZERO,
                            new KeyValue(writableHeight, expansionManager.fromHeight),
                            new KeyValue(writableWidth, expansionManager.fromWidth)),
                    new KeyFrame(Duration.millis(100),
                            new KeyValue(writableHeight, expansionManager.toHeight),
                            new KeyValue(writableWidth, expansionManager.toWidth))
            );
            timeline.play();

            timeline.setOnFinished((done) -> {
                System.out.println("done");
                expansionManager.layoutState = ExpansionManager.LayoutState.IDLE;
                timeline = null;
            });

        } else {
            System.out.println("idle");
            super.layoutChildren();
        }
    }

    @Override
    protected double computePrefHeight(double width) {
        if (expansionManager.layoutState == ExpansionManager.LayoutState.INITIALIZE) {
            expansionManager.fromHeight = super.computePrefHeight(width);
            return expansionManager.fromHeight;
        } else if (expansionManager.layoutState == ExpansionManager.LayoutState.ANIMATING) {
            return expansionManager.stepHeight;
        } else if (expansionManager.layoutState == ExpansionManager.LayoutState.REQUEST_ANIMATION) {
            expansionManager.fromHeight = getHeight();
            expansionManager.stepHeight = expansionManager.fromHeight;
            expansionManager.toHeight = super.computePrefHeight(width);
            return expansionManager.fromHeight;
        } else {
            return expansionManager.toHeight;
        }
    }

    @Override
    protected double computePrefWidth(double height) {
        if (expansionManager.layoutState == ExpansionManager.LayoutState.INITIALIZE) {
            expansionManager.fromWidth = super.computePrefWidth(height);
            return expansionManager.fromWidth;
        } else if (expansionManager.layoutState == ExpansionManager.LayoutState.ANIMATING) {
            return expansionManager.stepWidth;
        } else if (expansionManager.layoutState == ExpansionManager.LayoutState.REQUEST_ANIMATION) {
            expansionManager.fromWidth = getWidth();
            expansionManager.stepWidth = expansionManager.fromWidth;
            expansionManager.toWidth = super.computePrefWidth(height);
            return expansionManager.fromWidth;
        } else {
            System.out.println("BANG BANG BANG");
            return expansionManager.toWidth;
        }
    }

//    @Override
//    protected double computeMinWidth(double height) {
//        return computePrefWidth(height);
//    }
//
//    @Override
//    protected double computeMinHeight(double width) {
//        return computePrefHeight(width);
//    }
//
//    @Override
//    protected double computeMaxWidth(double height) {
//        return computePrefWidth(height);
//    }
//
//    @Override
//    protected double computeMaxHeight(double width) {
//        return computePrefHeight(width);
//    }

    private void expand() {
        System.out.println(expansionManager.layoutState);
//        if(contractedDimension == null)
//            contractedDimension = new Dimension2D(this.getWidth(), this.getHeight());
//        setPrefSize(expandedDimension.getWidth(), expandedDimension.getHeight());
        expansionManager.layoutState = ExpansionManager.LayoutState.REQUEST_ANIMATION;
        this.getChildren().setAll(title, listView);
        expanded = true;

    }

    private void contract() {
//        this.setPrefSize(contractedDimension.getWidth(), contractedDimension.getHeight());
        expansionManager.layoutState = ExpansionManager.LayoutState.REQUEST_ANIMATION;
        this.getChildren().setAll(title);
        expanded = false;

    }

    public String getTitle() {
        return title.getText();
    }

    public void setTitle(String title) {
        this.title.setText(title);
    }
}

Answer 1

我发现 ListView 是出现故障的原因。

基本上，除了第一次，每次您将列表添加到 VBox 时，您都可以在其容器外短暂地看到完整大小的列表，然后在时间线开始时, 它的大小已正确调整。

事实上，您可以在时间轴上添加延迟（例如一秒）：

timeline.setDelay(Duration.millis(1000));

如果你第二次展开框，你会在整秒钟内看到问题：

列表在 VBox 之外可见，因为它没有调整大小以适应它。当动画开始时，它会调整大小，问题就消失了。

当时我尝试了几种方法来调整列表的大小，但都没有成功。也许你可以解决它...

一个丑陋的解决方案是在每次展开框时创建一个新的列表实例：

private void expand() {
    expansionManager.layoutState = ExpansionManager.LayoutState.REQUEST_ANIMATION;
    // this works...    
    listView = new ListView<>(listItem);
    this.getChildren().setAll(title,listView);
    expanded = true;
}

寻找其他替代方案，我已将框 disableProperty() 绑定到时间轴，因此在扩展或收缩带标题的列表时您无法单击。

所以另一种解决方案是将列表 visibleProperty() 绑定到时间轴，但是您不会看到很好的增长效果。

还有第三种解决方案，它也与动画一致：在将列表添加到框中之前将不透明度设置为 0：

private void expand() {
    expansionManager.layoutState = ExpansionManager.LayoutState.REQUEST_ANIMATION;
    // this will avoid seeing the unresized listView
    listView.setOpacity(0);
    this.getChildren().setAll(title,listView);
    expanded = true;
}

并添加一个新的 KeyValue 增加列表 opacityProperty() 从 0 到 1 到时间线：

timeline.getKeyFrames().setAll(
    new KeyFrame(Duration.ZERO,
            new KeyValue(listView.opacityProperty(), 0),
            new KeyValue(writableHeight, expansionManager.fromHeight.get()),
            new KeyValue(writableWidth, expansionManager.fromWidth.get())),
    new KeyFrame(Duration.millis(300),
            new KeyValue(listView.opacityProperty(), 1),
            new KeyValue(writableHeight, expansionManager.toHeight.get()),
            new KeyValue(writableWidth, expansionManager.toWidth.get()))
);

现在您不会看到故障，并且在调整框大小时列表会很好地显示。事实上，我会增加第二个关键帧的持续时间。

编辑

我有另一种方法可以避免 'glitch'。它还可以改进动画，因为当标题列表收缩时列表也将可见。

收缩标题列表时，首先删除列表，因此super.computePrefHeight(width)和super.computePrefWidth(height)得到小框的新尺寸。这有一个明显的缺点，即在下一次扩展时，必须再次添加列表，并且会发生故障。

为了避免这种情况，我们不会删除该列表。首先，我们在 ExpansionManager 上创建两个新字段：

Double minWidth = 0.0;
Double minHeight = 0.0;

然后我们得到盒子的最小尺寸（在第一次展开时），并在每次收缩时使用它：

@Override
protected double computePrefHeight(double width) {
     ...
     if (expansionManager.layoutState == ExpansionManager.LayoutState.REQUEST_ANIMATION) {
        if(expansionManager.minHeight==0d){
            expansionManager.minHeight=getHeight();
        }
        expansionManager.fromHeight = getHeight();
        expansionManager.stepHeight = expansionManager.fromHeight;
        expansionManager.toHeight = expanded?super.computePrefHeight(width):
                                             expansionManager.minHeight;
        return expansionManager.fromHeight;
    }
}

@Override
protected double computePrefWidth(double height) {
    ...
    if (expansionManager.layoutState == ExpansionManager.LayoutState.REQUEST_ANIMATION) {
        if(expansionManager.minWidth==0d){
            expansionManager.minWidth=getWidth();
        }
        expansionManager.fromWidth = getWidth();
        expansionManager.stepWidth = expansionManager.fromWidth;
        expansionManager.toWidth = expanded?super.computePrefWidth(height):
                                            expansionManager.minWidth;
        return expansionManager.fromWidth;
    }
}

最后，我们需要隐藏任何收缩后的列表，否则会看到一个小边框，并将expand()和contract()方法更改为调用requestLayout()，假设框 children 列表不再修改（第一次调用除外）：

 @Override
protected void layoutChildren() {
        timeline.setOnFinished((done) -> {
            expansionManager.layoutState = ExpansionManager.LayoutState.IDLE;
            listView.setVisible(expanded);
            timeline = null;
        });
}

private void expand() {
    expansionManager.layoutState = ExpansionManager.LayoutState.REQUEST_ANIMATION;
    expanded = true;
    listView.setVisible(true);
    if(this.getChildren().size()==1){
        this.getChildren().add(listView);
    }
    requestLayout();
}

private void contract() {
    expansionManager.layoutState = ExpansionManager.LayoutState.REQUEST_ANIMATION;
    expanded = false;
    requestLayout();
}

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