JavaFX学习之样例5
该代码主要是timeline和进度条使用

import javafx.animation.*;import javafx.application.Application;import javafx.beans.property.*;import javafx.beans.value.*;import javafx.event.*;import javafx.geometry.Pos;import javafx.scene.Scene;import javafx.scene.control.*;import javafx.scene.layout.*;import javafx.scene.text.Text;import javafx.stage.Stage;import javafx.util.Duration;public class LabeledProgressBarSample extends Application {  public static void main(String[] args) { launch(args); }  @Override public void start(final Stage stage) {    stage.setScene(new Scene(createResettableProgressIndicatorBar()));    stage.show();  }  private VBox createResettableProgressIndicatorBar() {    final int    TOTAL_WORK = 18;    final String WORK_DONE_LABEL_FORMAT = "%.0f";    final ReadOnlyDoubleWrapper workDone  = new ReadOnlyDoubleWrapper();    final ProgressIndicatorBar bar = new ProgressIndicatorBar(        workDone.getReadOnlyProperty(),        TOTAL_WORK,        WORK_DONE_LABEL_FORMAT    );    final Timeline countDown = new Timeline(        new KeyFrame(Duration.seconds(0), new KeyValue(workDone, TOTAL_WORK)),  //初始化workDone等于total，也就是进度条满的        new KeyFrame(Duration.seconds(10), new KeyValue(workDone, 0))           //10秒内把workDone减到0。    );    countDown.play();    final Button resetButton = new Button("Reset");    resetButton.setOnAction(new EventHandler<ActionEvent>() {      @Override      public void handle(ActionEvent actionEvent) {        countDown.playFromStart();  //重新开始      }    });    final VBox layout = new VBox(20);    layout.setAlignment(Pos.CENTER);    layout.setStyle("-fx-background-color: cornsilk; -fx-padding: 20px;");    layout.getChildren().addAll(bar, resetButton);    return layout;  }}class ProgressIndicatorBar extends StackPane {  final private ReadOnlyDoubleProperty workDone;  final private double totalWork;  final private ProgressBar bar  = new ProgressBar();  final private Text        text = new Text();  final private String      labelFormatSpecifier;  final private static int DEFAULT_LABEL_PADDING = 5;  ProgressIndicatorBar(final ReadOnlyDoubleProperty workDone, final double totalWork, final String labelFormatSpecifier) {    this.workDone  = workDone;    this.totalWork = totalWork;    this.labelFormatSpecifier = labelFormatSpecifier;    syncProgress();    //监听workDone的变化，从而更新text和progress    workDone.addListener(new ChangeListener<Number>() {      @Override public void changed(ObservableValue<? extends Number> observableValue, Number number, Number number2) {        syncProgress();      }    });    bar.setMaxWidth(Double.MAX_VALUE); // allows the progress bar to expand to fill available horizontal space.    getChildren().setAll(bar, text);  }  // synchronizes the progress indicated with the work done.  private void syncProgress() {    if (workDone == null || totalWork == 0) {      text.setText("");      bar.setProgress(ProgressBar.INDETERMINATE_PROGRESS);    } else {      text.setText(String.format(labelFormatSpecifier, Math.ceil(workDone.get())));  //更新text      bar.setProgress(workDone.get() / totalWork);  //更新进度条    }    bar.setMinHeight(text.getBoundsInLocal().getHeight() + DEFAULT_LABEL_PADDING * 2);    bar.setMinWidth (text.getBoundsInLocal().getWidth()  + DEFAULT_LABEL_PADDING * 2);  }}

代码主要也就是timeline和progress二个的用法。fx最好的就是多了property，property里面多了方法。如上面的ReadOnlyDoubleWrapper，可以监控其值得变化。

String.format(labelFormatSpecifier, Math.ceil(workDone.get()));学习到了一个格式转化。