面向对象程序设计（Java）第十五章例题代码-J7chapte15

//FileName：App15_10.java import javafx.animation.KeyFrame; import javafx.animation.KeyValue; import javafx.animation.Timeline; import javafx.application.Application; import javafx.geometry.VPos; import javafx.scene.Scene; import javafx.scene.layout.Pane; import javafx.scene.text.Font; import javafx.scene.text.Text; import javafx.stage.Stage; import javafx.util.Duration; public class App15_10 extends Application{ @Override public void start(Stage stage){ Text t=new Text("滚动字幕"); t.setTextOrigin(VPos.TOP); t.setFont(Font.font(20)); Pane root=new Pane(t); root.setPrefSize(300,60); Scene scene=new Scene(root); stage.setScene(scene); stage.setTitle("时间轴动画程序设计"); stage.show(); double sceneWidth=scene.getWidth(); double tWidth=t.getLayoutBounds().getWidth(); KeyValue sKeyValue=new KeyValue(t.translateXProperty(),sceneWidth); KeyFrame sFrame=new KeyFrame(Duration.ZERO,sKeyValue); KeyValue eKeyValue=new KeyValue(t.translateXProperty(),-1.0*tWidth); KeyFrame eFrame=new KeyFrame(Duration.seconds(5),eKeyValue); Timeline timeline=new Timeline(sFrame,eFrame); timeline.setCycleCount(Timeline.INDEFINITE); timeline.play(); scene.widthProperty().addListener((prop,oldValue,newValue)->{ //去掉参数oldValue和newValue亦可 KeyValue kv=new KeyValue(t.translateXProperty(),scene.getWidth()); KeyFrame kf=new KeyFrame(Duration.ZERO,kv); timeline.stop(); timeline.getKeyFrames().clear(); timeline.getKeyFrames().addAll(kf,eFrame); timeline.play(); }); } }