css - JavaFX 中有两种颜色的背景？

Question

在 JavaFX 2 中，是否可以使用 CSS 创建具有 2 种颜色的背景？想想例如高度为 10 像素的 TableCell。我希望前 2 像素(垂直)为红色，其余 8 像素(垂直)应保持默认背景色。是否可以在 JavaFX 2 中使用 CSS？如何？

示例:

原始背景:

期望的结果:

(上面2个像素被红色代替)

感谢您对此的任何提示!

Answer 1

我使用了一个简单的背景颜色层来产生红色高光(类似于 Stefan 建议的解决方案)。

/**
 * file: table.css
 *   Place in same directory as TableViewPropertyEditorWithCSS.java.
 *   Have your build system copy this file to your build output directory.
 **/

.highlighted-cell {
  -fx-text-fill: -fx-text-inner-color;
  -fx-background-color: firebrick, gainsboro;
  -fx-background-insets: 0, 2 0 0 0;
}

对于像堆栈 Pane 这样的标准区域，您真正需要做的就是应用上述 css(减去 -fx-text-fill)以获得所需的结果。

---

这是另一种使用渐变定义颜色的巧妙方法:

-fx-background-color: 
  linear-gradient(
    from 0px 0px to 0px 2px, 
      firebrick, firebrick 99%, 
    gainsboro
  );

---

在下面的屏幕截图中，如果值为 false，则值单元格会突出显示(通过对其应用 highlighted-cell css 类)。

高亮单元格样式类切换逻辑:

public void updateItem(Object item, boolean empty) {
  super.updateItem(item, empty);
  if (empty) {
    ....
    getStyleClass().remove("highlighted-cell");
  } else {
    if (getItem() instanceof Boolean && (Boolean.FALSE.equals((Boolean) getItem()))) {
      getStyleClass().add("highlighted-cell");
    } else {
      getStyleClass().remove("highlighted-cell");
    }
    ...
  }
}

---

当 highlighted-cell 样式类应用于标准表格单元格时(在 updateItem 调用自定义单元格期间)看起来不错，但确实有一些缺点。表格配色方案非常微妙和复杂。它具有奇数/偶数值的高亮显示、选定行的高亮显示、选定悬停行的高亮显示、聚焦行和单元格的高亮显示等。此外，它还有上述所有内容的各种组合。直接在 highlight-cell 类中设置 background-color 是一种实现你想要的东西的蛮力方式，因为它没有考虑所有这些其他微妙之处，只是覆盖了它们，所以使用这个突出显示的单元格无论应用了何种临时 css 伪类状态，样式始终看起来相同。

这确实很好，但更好的解决方案是根据伪类状态为突出显示的单元格着色不同。不过，这是一件非常棘手的事情，您可能会浪费大量时间来尝试各种状态和 css 选择器组合，以尝试获得漂亮的变化亮点。总而言之，对于这个例子，我似乎不值得付出额外的努力，尽管它可能适合你。

---

测试程序(对此的长度和复杂性表示歉意，将样式突出显示逻辑集成到现有程序中对我来说更容易):

import java.lang.reflect.*;
import java.util.logging.*;
import javafx.application.Application;
import javafx.beans.property.*;
import javafx.beans.value.*;
import javafx.collections.*;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.TableColumn.CellEditEvent;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.*;
import javafx.stage.Stage;
import javafx.util.Callback;
// click in the value column (a couple of times) to edit the value in the column.
// property editors are defined only for String and Boolean properties.
// change focus to something else to commit the edit.
public class TableViewPropertyEditorWithCSS extends Application {

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

  @Override
  public void start(Stage stage) {
    final Person aPerson = new Person("Fred", false, false, "Much Ado About Nothing");
    final Label currentObjectValue = new Label(aPerson.toString());
    TableView<NamedProperty> table = new TableView();
    table.setEditable(true);
    table.setItems(createNamedProperties(aPerson));
    TableColumn<NamedProperty, String> nameCol = new TableColumn("Name");
    nameCol.setCellValueFactory(new PropertyValueFactory<NamedProperty, String>("name"));
    TableColumn<NamedProperty, Object> valueCol = new TableColumn("Value");
    valueCol.setCellValueFactory(new PropertyValueFactory<NamedProperty, Object>("value"));
    valueCol.setCellFactory(new Callback<TableColumn<NamedProperty, Object>, TableCell<NamedProperty, Object>>() {
      @Override
      public TableCell<NamedProperty, Object> call(TableColumn<NamedProperty, Object> param) {
        return new EditingCell();
      }
    });
    valueCol.setOnEditCommit(
            new EventHandler<CellEditEvent<NamedProperty, Object>>() {
      @Override
      public void handle(CellEditEvent<NamedProperty, Object> t) {
        int row = t.getTablePosition().getRow();
        NamedProperty property = (NamedProperty) t.getTableView().getItems().get(row);
        property.setValue(t.getNewValue());
        currentObjectValue.setText(aPerson.toString());
      }
    });
    table.getColumns().setAll(nameCol, valueCol);
    table.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
    VBox layout = new VBox(10);
    layout.setStyle("-fx-background-color: cornsilk; -fx-padding: 10;");
    layout.getChildren().setAll(
            currentObjectValue,
            table);
    VBox.setVgrow(table, Priority.ALWAYS);

    Scene scene = new Scene(layout, 650, 600);
    scene.getStylesheets().add(getClass().getResource("table.css").toExternalForm());
    stage.setScene(scene);
    stage.show();
  }

  private ObservableList<NamedProperty> createNamedProperties(Object object) {
    ObservableList<NamedProperty> properties = FXCollections.observableArrayList();
    for (Method method : object.getClass().getMethods()) {
      String name = method.getName();
      Class type = method.getReturnType();
      if (type.getName().endsWith("Property")) {
        try {
          properties.add(new NamedProperty(name, (Property) method.invoke(object)));
        } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException ex) {
          Logger.getLogger(TableViewPropertyEditorWithCSS.class.getName()).log(Level.SEVERE, null, ex);
        }
      }
    }
    return properties;
  }

  public class NamedProperty {

    public NamedProperty(String name, Property value) {
      nameProperty.set(name);
      valueProperty = value;
    }
    private StringProperty nameProperty = new SimpleStringProperty();

    public StringProperty nameProperty() {
      return nameProperty;
    }

    public StringProperty getName() {
      return nameProperty;
    }

    public void setName(String name) {
      nameProperty.set(name);
    }
    private Property valueProperty;

    public Property valueProperty() {
      return valueProperty;
    }

    public Object getValue() {
      return valueProperty.getValue();
    }

    public void setValue(Object value) {
      valueProperty.setValue(value);
    }
  }

  public class Person {

    private final SimpleStringProperty firstName;
    private final SimpleBooleanProperty married;
    private final SimpleBooleanProperty hasChildren;
    private final SimpleStringProperty favoriteMovie;

    private Person(String firstName, Boolean isMarried, Boolean hasChildren, String favoriteMovie) {
      this.firstName = new SimpleStringProperty(firstName);
      this.married = new SimpleBooleanProperty(isMarried);
      this.hasChildren = new SimpleBooleanProperty(hasChildren);
      this.favoriteMovie = new SimpleStringProperty(favoriteMovie);
    }

    public SimpleStringProperty firstNameProperty() {
      return firstName;
    }

    public SimpleBooleanProperty marriedProperty() {
      return married;
    }

    public SimpleBooleanProperty hasChildrenProperty() {
      return hasChildren;
    }

    public SimpleStringProperty favoriteMovieProperty() {
      return favoriteMovie;
    }

    public String getFirstName() {
      return firstName.get();
    }

    public void setFirstName(String fName) {
      firstName.set(fName);
    }

    public Boolean getMarried() {
      return married.get();
    }

    public void setMarried(Boolean isMarried) {
      married.set(isMarried);
    }

    public Boolean getHasChildren() {
      return hasChildren.get();
    }

    public void setHasChildren(Boolean hasChildren) {
      this.hasChildren.set(hasChildren);
    }

    public String getFavoriteMovie() {
      return favoriteMovie.get();
    }

    public void setFavoriteMovie(String movie) {
      favoriteMovie.set(movie);
    }

    @Override
    public String toString() {
      return firstName.getValue() + ", isMarried? " + married.getValue() + ", hasChildren? " + hasChildren.getValue() + ", favoriteMovie: " + favoriteMovie.get();
    }
  }

  class EditingCell extends TableCell<NamedProperty, Object> {

    private TextField textField;
    private CheckBox checkBox;

    public EditingCell() {
    }

    @Override
    public void startEdit() {
      if (!isEmpty()) {
        super.startEdit();
        if (getItem() instanceof Boolean) {
          createCheckBox();
          setText(null);
          setGraphic(checkBox);
        } else {
          createTextField();
          setText(null);
          setGraphic(textField);
          textField.selectAll();
        }
      }
    }

    @Override
    public void cancelEdit() {
      super.cancelEdit();
      if (getItem() instanceof Boolean) {
        setText(getItem().toString());
      } else {
        setText((String) getItem());
      }
      setGraphic(null);
    }

    @Override
    public void updateItem(Object item, boolean empty) {
      super.updateItem(item, empty);
      if (empty) {
        setText(null);
        setGraphic(null);
        getStyleClass().remove("highlighted-cell");
      } else {
        if (getItem() instanceof Boolean && (Boolean.FALSE.equals((Boolean) getItem()))) {
          getStyleClass().add("highlighted-cell");
        } else {
          getStyleClass().remove("highlighted-cell");
        }
        if (isEditing()) {
          if (getItem() instanceof Boolean) {
            if (checkBox != null) {
              checkBox.setSelected(getBoolean());
            }
            setText(null);
            setGraphic(checkBox);
          } else {
            if (textField != null) {
              textField.setText(getString());
            }
            setText(null);
            setGraphic(textField);
          }
        } else {
          setText(getString());
          setGraphic(null);
        }
      }
    }

    private void createTextField() {
      textField = new TextField(getString());
      textField.setMinWidth(this.getWidth() - this.getGraphicTextGap() * 2);
      textField.focusedProperty().addListener(new ChangeListener<Boolean>() {
        @Override
        public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) {
          if (!newValue) {
            commitEdit(textField.getText());
          }
        }
      });
    }

    private void createCheckBox() {
      checkBox = new CheckBox();
      checkBox.setSelected(getBoolean());
      checkBox.setMinWidth(this.getWidth() - this.getGraphicTextGap() * 2);
      checkBox.focusedProperty().addListener(new ChangeListener<Boolean>() {
        @Override
        public void changed(ObservableValue<? extends Boolean> observable, Boolean oldValue, Boolean newValue) {
          if (!newValue) {
            commitEdit(checkBox.isSelected());
          }
        }
      });
    }

    private String getString() {
      return getItem() == null ? "" : getItem().toString();
    }

    private Boolean getBoolean() {
      return getItem() == null ? false : (Boolean) getItem();
    }
  }
}