这是可能的,但可能并不像您希望的那么简单。为了确定特定的布局坐标Cell
在一个ListView
(or TableView/TreeView
)您需要有权访问该特定的Cell
目的。最好的方法(也许是 JavaFX 2.2 中唯一的方法)是为容器提供自定义的Cell
and CellFactory
暴露了每个Cell
。你如何揭露Cell
取决于你划清界限的触发因素是什么。
根据您的插图,您将需要访问每个单元格ListView
s 已填充。你可以用List<ListCell<String>>
领域中的CellFactory
。我会在这里提到一个警告ListCell
s. The ListViewSkin
将重复使用Cell
尽可能。这意味着,如果您要尝试填充并连接一个最终滚动的列表,那么将行保持在正确的位置将会更加困难。我建议尝试确保所有列表项都适合屏幕。
下面是一个示例,注释中包含一些注释。请注意,获取正确的坐标来绘制您的Line
可能需要计算 SceneGraph 的偏移量,但我在本例中没有这样做。
package listviewcellposition;
import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.scene.paint.Color;
import javafx.scene.shape.Line;
import javafx.stage.Stage;
import javafx.util.Callback;
public class ListViewCellPosition extends Application {
// CustomCellFactory for creating CustomCells
public class CustomCellFactory implements
Callback<ListView<String>, ListCell<String>> {
List<ListCell<String>> allCells = new ArrayList<>();
@Override
public ListCell<String> call(final ListView<String> p) {
final CustomCell cell = new CustomCell();
allCells.add(cell);
return cell;
}
public List<ListCell<String>> getAllCells() {
return allCells;
}
}
// CustomCell is where the exposure occurs. Here, it's based on the
// Cell being selected in the ListView. You could choose a different
// trigger here but you'll need to explore.
public class CustomCell extends ListCell<String> {
// General display stuff
@Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setText(null);
setGraphic(null);
} else {
setText(item == null ? "" : item);
setGraphic(null);
}
}
}
@Override
public void start(Stage primaryStage) {
// This pane will contain the lines after they are created.
// I set it into an AnchorPane to avoid having to deal with
// resizing.
Pane linePane = new Pane();
AnchorPane pane = new AnchorPane();
pane.setPrefSize(100, 250);
AnchorPane.setBottomAnchor(linePane, 0.0);
AnchorPane.setLeftAnchor(linePane, 0.0);
AnchorPane.setRightAnchor(linePane, 0.0);
AnchorPane.setTopAnchor(linePane, 0.0);
pane.getChildren().add(linePane);
ListView<String> lView = new ListView<>();
lView.setPrefSize(100, 250);
CustomCellFactory lCellFactory = new CustomCellFactory();
lView.setCellFactory(lCellFactory);
ListView<String> rView = new ListView<>();
rView.setPrefSize(100, 250);
CustomCellFactory rCellFactory = new CustomCellFactory();
rView.setCellFactory(rCellFactory);
lView.getItems().addAll("Bill", "Doctor", "Steve", "Joanne");
rView.getItems().addAll("Seuss", "Rowling", "King", "Shakespeare");
HBox root = new HBox();
root.getChildren().addAll(lView, pane, rView);
Scene scene = new Scene(root, 300, 250);
primaryStage.setScene(scene);
primaryStage.show();
connectCells(lCellFactory, "Bill", rCellFactory, "Shakespeare", linePane);
connectCells(lCellFactory, "Doctor", rCellFactory, "Seuss", linePane);
connectCells(lCellFactory, "Steve", rCellFactory, "King", linePane);
connectCells(lCellFactory, "Joanne", rCellFactory, "Rowling", linePane);
}
// Looks up the ListCell<> for each String and creates a Line
// with the coordinates from each Cell. The calculation is very
// contrived because I know that all the components have the same
// x-coordinate. You'll need more complicated calculations if your
// containers are not aligned this way.
private void connectCells(CustomCellFactory lCellFactory, String lVal,
CustomCellFactory rCellFactory, String rVal, Pane linePane) {
List<ListCell<String>> lList = lCellFactory.getAllCells();
ListCell<String> lCell = null;
for (ListCell<String> lc : lList) {
if (lc.getItem() != null && lc.getItem().equals(lVal)) {
lCell = lc;
break;
}
}
List<ListCell<String>> rList = rCellFactory.getAllCells();
ListCell<String> rCell = null;
for (ListCell<String> rc : rList) {
if (rc.getItem() != null && rc.getItem().equals(rVal)) {
rCell = rc;
break;
}
}
if (lCell != null && rCell != null) {
double startY = lCell.getLayoutY() +
(lCell.getBoundsInLocal().getHeight() / 2);
double endY = rCell.getLayoutY() +
(rCell.getBoundsInLocal().getHeight() / 2);
Line line = new Line(0, startY,
linePane.getBoundsInParent().getWidth(), endY);
line.setStrokeWidth(2);
line.setStroke(Color.BLACK);
linePane.getChildren().add(line);
}
}
public static void main(String[] args) {
launch(args);
}
}