如何使用JavaFX中的CSS制作动画？

Is it possible to change style gradually,for example make some transition?

是.

您将需要使用setStyle而不是样式类,因为类将是在css中定义的静态事件.在JavaFX css中没有直接的支持动画.您需要在Java代码中执行动画步骤来修改css样式.

当您想使用css执行转换时,我只会真正推荐此方法,因为没有相应的Java API可以轻松获得.

要处理动画,您可以使用标准的javafx动画Timeline来处理CSS样式属性所依赖的属性.

例如,将您的样式属性绑定到字符串.然后在时间轴中更改要更改的组件(在本例中为colorStringProperty).

warningButton.styleProperty().bind(
    new SimpleStringProperty("-fx-base: ")
        .concat(colorStringProperty)
        .concat(";")
        .concat("-fx-font-size: 20px;")
);

这是一个示例,它使用css闪烁一个按钮,当按下时,它的基本颜色从灰色逐渐变为红色.

import javafx.animation.*;
import javafx.application.Application;
import javafx.beans.property.*;
import javafx.beans.value.*;
import javafx.event.*;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.image.*;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Duration;

/** Shows how you can modify css styles dynamically using a timeline. */
public class Warning extends Application {

    private static final String BACKGROUND = "http://bobgreiner.tripod.com/1cc2ce10.jpg"; 

    @Override
    public void start(Stage stage) throws Exception{
        final ObjectProperty<Color> warningColor = new SimpleObjectProperty<>(Color.GRAY);
        final StringProperty colorStringProperty = createWarningColorStringProperty(warningColor);

        StackPane layout = new StackPane();
        layout.getChildren().addAll(
                new ImageView(new Image(BACKGROUND)),createWarningButton(
                        warningColor,colorStringProperty
                )
        );
        stage.setScene(new Scene(layout));
        stage.show();
    }

    private StringProperty createWarningColorStringProperty(final ObjectProperty<Color> warningColor) {
        final StringProperty colorStringProperty = new SimpleStringProperty();
        setColorStringFromColor(colorStringProperty,warningColor);
        warningColor.addListener(new ChangeListener<Color>() {
            @Override
            public void changed(ObservableValue<? extends Color> observableValue,Color oldColor,Color newColor) {
                setColorStringFromColor(colorStringProperty,warningColor);
            }
        });

        return colorStringProperty;
    }

    private Button createWarningButton(final ObjectProperty<Color> warningColor,StringProperty colorStringProperty) {
        final Button warningButton = new Button("Warning! Warning!");
        warningButton.styleProperty().bind(
                new SimpleStringProperty("-fx-base: ")
                        .concat(colorStringProperty)
                        .concat(";")
                        .concat("-fx-font-size: 20px;")
        );

        warningButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent actionEvent) {
                Timeline flash = new Timeline(
                    new KeyFrame(Duration.seconds(0),new KeyValue(warningColor,Color.GRAY,Interpolator.LINEAR)),new KeyFrame(Duration.seconds(0.25),new KeyFrame(Duration.seconds(1),Color.RED,new KeyFrame(Duration.seconds(1.25),Interpolator.LINEAR))
                );
                flash.setCycleCount(6);
                flash.setAutoReverse(true);
                flash.play();
            }
        });

        return warningButton;
    }

    private void setColorStringFromColor(StringProperty colorStringProperty,ObjectProperty<Color> color) {
        colorStringProperty.set(
                "rgba("
                        + ((int) (color.get().getRed()   * 255)) + ","
                        + ((int) (color.get().getGreen() * 255)) + ","
                        + ((int) (color.get().getBlue()  * 255)) + ","
                        + color.get().getOpacity() +
                ")"
        );
    }

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