JavaFX進(jìn)度條

進(jìn)度條(ProgressBar)可視化JavaFX應(yīng)用程序中的操作進(jìn)度。

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.ProgressBar;
import javafx.stage.Stage;
// create W w  w . y I IB  A I.C o m 
public class Main extends Application {

  @Override
  public void start(Stage stage) {
    Group root = new Group();
    Scene scene = new Scene(root, 260, 80);
    stage.setScene(scene);

    Group g = new Group();

    ProgressBar p2 = new ProgressBar();

    g.getChildren().add(p2);
    scene.setRoot(g);
    stage.show();
  }

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

上面的代碼生成以下結(jié)果。

創(chuàng)建ProgressBar

以下代碼顯示如何通過(guò)傳遞progress值來(lái)創(chuàng)建ProgressBar。

ProgressBar pb = new ProgressBar(0.6);

還可以使用空構(gòu)造函數(shù)創(chuàng)建沒(méi)有參數(shù)的進(jìn)度條。然后使用setProgress()方法分配值。如果我們不能確定任務(wù)的完全完成時(shí)間，可以設(shè)置進(jìn)度條在不確定模式，直到確定任務(wù)的長(zhǎng)度。

以下代碼顯示如何創(chuàng)建一個(gè)完成25％的進(jìn)度條(ProgressBar)。

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Task;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

// by W  W w . yIIB aI.C  O  M
public class Main extends Application {
    Task copyWorker;

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

    @Override
    public void start(Stage primaryStage) {
        Group root = new Group();
        Scene scene = new Scene(root, 330, 120, Color.WHITE);

        BorderPane mainPane = new BorderPane();
        root.getChildren().add(mainPane);

        final Label label = new Label("Files Transfer:");
        final ProgressBar progressBar = new ProgressBar(0);

        final HBox hb = new HBox();
        hb.setSpacing(5);
        hb.setAlignment(Pos.CENTER);
        hb.getChildren().addAll(label, progressBar);
        mainPane.setTop(hb);

        final Button startButton = new Button("Start");
        final Button cancelButton = new Button("Cancel");
        final HBox hb2 = new HBox();
        hb2.setSpacing(5);
        hb2.setAlignment(Pos.CENTER);
        hb2.getChildren().addAll(startButton, cancelButton);
        mainPane.setBottom(hb2);
        startButton.setOnAction(new EventHandler<ActionEvent>() {
            public void handle(ActionEvent event) {
                startButton.setDisable(true);
                progressBar.setProgress(0);
                cancelButton.setDisable(false);
                copyWorker = createWorker();
                progressBar.progressProperty().unbind();
                progressBar.progressProperty().bind(copyWorker.progressProperty());
                copyWorker.messageProperty().addListener(new ChangeListener<String>() {
                    public void changed(ObservableValue<? extends String> observable, String oldValue,
                            String newValue) {
                        System.out.println(newValue);
                    }
                });
                new Thread(copyWorker).start();
            }
        });
        cancelButton.setOnAction(new EventHandler<ActionEvent>() {
            public void handle(ActionEvent event) {
                startButton.setDisable(false);
                cancelButton.setDisable(true);
                copyWorker.cancel(true);
                progressBar.progressProperty().unbind();
                progressBar.setProgress(0);
                System.out.println("cancelled.");
            }
        });
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public Task createWorker() {
        return new Task() {
            @Override
            protected Object call() throws Exception {
                for (int i = 0; i < 10; i++) {
                    Thread.sleep(2000);
                    updateMessage("2000 milliseconds");
                    updateProgress(i + 1, 10);
                }
                return true;
            }
        };
    }
}

上面的代碼生成以下結(jié)果。