JavaFX8 treeTableView自定义折叠根项

Question

如何自定义树根项目的折叠外观？通过自定义我的意思是设置一个图像并将小三角形(/新图像)放在其单元格中.

提前致谢.

Answer 1

以下示例根据是否展开根来自定义根节点的图形(通过在视图的图像和树项的展开属性之间使用图形ImageView上的绑定).

通过使用箭头的填充设置进行播放,样本还使小三角形(公开箭头)相对于图形图像垂直居中 - 您需要根据视图调整填充,因为居中不是自动的.

如果要将显示箭头的形状更改为不同的内容,请参阅Uluk的答案:JavaFX:使用自定义节点作为TreeView的折叠/展开分支开关.

CustomTree.java

import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.image.*;
import javafx.stage.Stage;

public class CustomTree extends Application {

    @SuppressWarnings("unchecked")
    @Override
    public void start(Stage stage) throws Exception {
        Image expandedImage  = new Image(
                "http://icons.iconarchive.com/icons/pelfusion/christmas-shadow-2/64/Tree-icon.png"
        );
        Image collapsedImage = new Image(
                "http://icons.iconarchive.com/icons/pelfusion/christmas-shadow/64/Tree-icon.png"
        );

        ImageView rootGraphic = new ImageView(expandedImage);

        TreeItem<String> root = new TreeItem<>("Root Node");
        root.setGraphic(rootGraphic);
        root.getChildren().setAll(
                new TreeItem<>("Item 1"),
                new TreeItem<>("Item 2"),
                new TreeItem<>("Item 3")
        );

        rootGraphic.imageProperty().bind(Bindings
                .when(root.expandedProperty())
                    .then(expandedImage)
                    .otherwise(collapsedImage)
        );
        root.setExpanded(true);

        TreeView<String> treeView = new TreeView<>(root);
        treeView.setPrefSize(300, 200);

        Scene scene = new Scene(treeView);
        scene.getStylesheets().add(
                getClass().getResource(
                        "custom-tree.css"
                ).toExternalForm()
        );
        stage.setScene(scene);
        stage.show();
    }

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

定制tree.css

.root {
    -fx-font-size: 30px;
}

.tree-cell > .tree-disclosure-node {
  -fx-padding: 24 6 24 8;
}

Answer 2

查看默认样式表modena.css,您可以从jre/lib/ext中的jfxrt.jar文件中提取该样式表,或者在线查找.图形被定义为那里的路径:

.tree-cell > .tree-disclosure-node,
.tree-table-row-cell > .tree-disclosure-node {
    -fx-padding: 4 6 4 8;
    -fx-background-color: transparent;
}
.tree-cell > .tree-disclosure-node > .arrow,
.tree-table-row-cell > .tree-disclosure-node > .arrow {
    -fx-background-color: -fx-text-background-color;
    -fx-padding: 0.333333em 0.229em 0.333333em 0.229em; /* 4 */
    -fx-shape: "M 0 -3.5 L 4 0 L 0 3.5 z";
}
.tree-cell:expanded > .tree-disclosure-node > .arrow,
.tree-table-row-cell:expanded > .tree-disclosure-node > .arrow {
    -fx-rotate: 90;
}

您可以在自己的CSS中覆盖这些规则.css中引用的箭头是Region,因此您可以根据-fx-background-image需要定义a .