#18: Creating Custom ListCell<T> for Ingredients

src/main/java/de/hitec/nhplus/medication/IngredientListCell.java

@@ -0,0 +1,92 @@
+package de.hitec.nhplus.medication;
+
+import javafx.beans.value.ObservableValue;
+import javafx.geometry.Insets;
+import javafx.scene.control.Button;
+import javafx.scene.control.ListCell;
+import javafx.scene.control.ListView;
+import javafx.scene.control.TextField;
+import javafx.scene.layout.BorderPane;
+import javafx.scene.text.Text;
+
+public class IngredientListCell extends ListCell<Ingredient> {
+    private final TextField textField;
+    private final Button deleteButton;
+
+    private static final double BUILTIN_BORDER_WIDTH = 1;
+    private static final double CELL_SPACING = 4;
+    private static final double CELL_PADDING = 4;
+    private static final double BUTTON_PADDING_X = 8;
+    private static final double BUTTON_PADDING_Y = 4;
+    private final double totalSpacing;
+
+    public IngredientListCell() {
+        this.setPadding(new Insets(CELL_PADDING));
+
+        textField = new TextField();
+        textField.setPromptText("Inhaltsstoff");
+        textField.textProperty().addListener(this::onTextFieldUpdate);
+
+        deleteButton = new Button("-");
+        deleteButton.setPadding(new Insets(
+                BUTTON_PADDING_Y,
+                BUTTON_PADDING_X,
+                BUTTON_PADDING_Y,
+                BUTTON_PADDING_X
+        ));
+        deleteButton.setOnAction(event -> getListView().getItems().remove(this));
+
+        // Calculate Delete Button Width
+        Text textNode = new Text(deleteButton.getText());
+        textNode.setFont(deleteButton.getFont());
+        double calculatedDeleteButtonWidth = textNode.getLayoutBounds().getWidth() + BUTTON_PADDING_X * 2;
+
+        totalSpacing = BUILTIN_BORDER_WIDTH * 2 // List View
+                       + CELL_PADDING * 2
+                       + CELL_SPACING
+                       + calculatedDeleteButtonWidth;
+    }
+
+    @Override
+    protected void updateItem(Ingredient item, boolean empty) {
+        super.updateItem(item, empty);
+        if (empty || item == null) {
+            setGraphic(null);
+        } else {
+            String oldText = textField.getText();
+            String newText = oldText != null && !oldText.isEmpty() ? oldText : item.getName();
+            textField.setText(newText);
+
+            BorderPane cellPane = new BorderPane();
+            cellPane.setCenter(textField);
+            cellPane.setRight(deleteButton);
+            BorderPane.setMargin(deleteButton, new Insets(0, 0, 0, CELL_SPACING));
+            setGraphic(cellPane);
+        }
+    }
+
+    private void onTextFieldUpdate(ObservableValue<? extends String> observable, String oldValue, String newValue) {
+        getItem().setName(textField.getText());
+
+        textField.setMinWidth(getTextFieldRequiredWidth(textField));
+
+        ListView<Ingredient> listView = getListView();
+        double max = listView.lookupAll("*")
+                .stream()
+                .filter(node -> node instanceof IngredientListCell)
+                .mapToDouble(node -> getTextFieldRequiredWidth(((IngredientListCell) node).textField))
+                .max()
+                .orElse(0);
+
+        getListView().setMinWidth(max + totalSpacing);
+    }
+
+    private double getTextFieldRequiredWidth(TextField textField) {
+        Text textNode = new Text(textField.getText());
+        textNode.setFont(textField.getFont());
+        return textNode.getLayoutBounds().getWidth()
+               + textField.getPadding().getLeft()
+               + textField.getPadding().getRight()
+               + BUILTIN_BORDER_WIDTH * 2;
+    }
+}