JavaFXsetHgrow/系結屬性無限擴展

這是我的代碼：

public class TestPanel extends ScrollPane {

    final int SPACING = 5;
    final int ROW_MAX = 6;

    public TestPanel(ArrayList<Item> items) {

        VBox root = new VBox(); 
        root.setSpacing(SPACING);
        HBox row = null;

        int count = 0;
        for (Item item: items){
            if (count == ROW_MAX || row == null){
                row = new HBox();
                row.setSpacing(SPACING);

                root.getChildren().add(row);
                count = 0;
            }

            CustomBox box = new customBox(item);
            row.getChildren().add(box);

            HBox.setHgrow(box, Priority.ALWAYS);

            //box.prefWidthProperty().bind(row.widthProperty());      // Worked for GridPane

            count  ;
        }

        setFitToWidth(true);
        setContent(root);

    }

這是我放置在 V 和 H 框中的自定義框節點元素

public class CustomBox extends StackPane {

    private Items item;
    private Rectangle square;

    private int size = 20; // Irrelevent

    public CustomBox(NewAirbnbListing item) {
        this.item= item;

        setPadding(new Insets(5, 5, 5, 5));

        square = new Rectangle(size, size, Color.RED);


        square.widthProperty().bind(widthProperty());
        //square.heightProperty().bind(heightProperty());


        minHeightProperty().bind(widthProperty()); // Maintains aspect ratio

        getChildren().add(square);

    }

錯誤：粉紅色是框，灰色是用于視覺測驗的 StackPane 的背景顏色。

我想做的事：

我想要什么：我希望 CustomBox 內的矩形（以及稍后我將添加的其他組件）填充它們所在的 StackPane 的大小，并在調整視窗大小時改變它們的大小。我基本上希望他們模仿那個窗格的大小。

Now to try explain whats going on, basically I have a class that's basically a square (There's going to be more stuff later) and I want to fill my "grid" with. When I first did this I used a GridPane to extend my class, I also used the commented out code to bind the properties and it worked "perfectly", it resized how I wanted with no issues, except the fact it lagged like crazy because the items ArrayList contains thousands of items so this will be a very long list. And then later when I was implementing the boxes to store images, that's when the massive lag problems started. My solution to this was to replace the GridPane with the HBox and VBox combo, and it very much fixed the lag issue, it also lets me do things I can't do with the GridPane. However, the problem in the gif I linked is what I'm facing. I've tried every combination of binding properties that I can think of but it still expands like crazy and I just have no idea whats causing it so I really hope someone here can help me out. I don't know tonnes about JavaFX but I'm here to learn, any help is greatly appreciated.

uj5u.com熱心網友回復：

我相信您的問題的根本原因在于：square寬度與寬度系結CustomBox。你可能想知道這是怎么回事。您允許 CustomBox 寬度依賴于其內容（又名正方形），而您的正方形寬度依賴于其父寬度..因為現在這兩個寬度相互依賴..寬度呈指數增長..

解決此問題的一種可能方法是根據 ScrollPane 視口寬度手動計算 CustomBox 大小。這樣您就可以手動控制父寬度，并且內容寬度由系結處理。

TestPanel 中的代碼將是：

private DoubleProperty size = new SimpleDoubleProperty();

double padding = 4; // 2px on either side
viewportBoundsProperty().addListener((obs, old, bounds) -> {
    size.setValue((bounds.getWidth() - padding - ((ROW_MAX - 1) * SPACING)) / ROW_MAX);
});

CustomBox box = new CustomBox(item);
box.minWidthProperty().bind(size);

完整的作業演示如下：

import javafx.application.Application;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ScrollPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

import java.util.ArrayList;
import java.util.List;
import java.util.stream.IntStream;

public class ScrollPaneContentDemo extends Application {
    @Override
    public void start(Stage stage) throws Exception {
        List<Item> items = new ArrayList<>();
        IntStream.range(1, 1000).forEach(i -> items.add(new Item()));
        TestPanel root = new TestPanel(items);
        Scene scene = new Scene(root, 500, 500);
        stage.setScene(scene);
        stage.setTitle("ScrollPaneContent Demo");
        stage.show();
    }

    class TestPanel extends ScrollPane {
        private final int SPACING = 5;
        private final int ROW_MAX = 6;
        private DoubleProperty size = new SimpleDoubleProperty();

        public TestPanel(List<Item> items) {
            final VBox root = new VBox();
            root.setSpacing(SPACING);
            HBox row = null;
            int count = 0;
            for (Item item : items) {
                if (count == ROW_MAX || row == null) {
                    row = new HBox();
                    row.setSpacing(SPACING);
                    root.getChildren().add(row);
                    count = 0;
                }

                CustomBox box = new CustomBox(item);
                box.minWidthProperty().bind(size);
                row.getChildren().add(box);
                HBox.setHgrow(box, Priority.ALWAYS);
                count  ;
            }
            setFitToWidth(true);
            setContent(root);

            double padding = 4;
            viewportBoundsProperty().addListener((obs, old, bounds) -> {
                size.setValue((bounds.getWidth() - padding - ((ROW_MAX - 1) * SPACING)) / ROW_MAX);
            });
        }
    }

    class CustomBox extends StackPane {
        private Item item;
        private Rectangle square;
        private int size = 20;

        public CustomBox(Item item) {
            setStyle("-fx-background-color:#99999950;");
            this.item = item;
            setPadding(new Insets(5, 5, 5, 5));
            square = new Rectangle(size, size, Color.RED);
            square.widthProperty().bind(widthProperty());
            square.heightProperty().bind(heightProperty());

            maxHeightProperty().bind(minWidthProperty());
            maxWidthProperty().bind(minWidthProperty());
            minHeightProperty().bind(minWidthProperty());
            getChildren().add(square);
        }
    }

    class Item {
    }
}

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