在方法内更新JavaFX舞台。

huangapple
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英文:

Update JavaFX stage within method

问题

  1. 我正在编写一个程序，需要使用大量数据进行多次计算，而且需要一段时间才能完成。这就是为什么我想要更新并通知用户程序当前已完成的百分比。但是我不知道如何在计算方法内部更新阶段。
  3. public void calculate() {
  4.     // 在这里我想要更改“百分比文本”
  5.     // 并更新舞台。
  6. }
英文:

I am writing a program that uses a lot of data to do several calculations and it takes quite a while to finish. This is why I want to update and inform the user on the current percentage of the program being done. However I don't know how I can update the stage within the calculation method.

  1. import javafx.application.Application;
  2. import javafx.event.ActionEvent;
  3. import javafx.event.EventHandler;
  4. import javafx.geometry.Insets;
  5. import javafx.scene.Scene;
  6. import javafx.scene.control.Button;
  7. import javafx.scene.layout.GridPane;
  8. import javafx.scene.layout.Pane;
  9. import javafx.scene.layout.VBox;
  10. import javafx.scene.text.Text;
  11. import javafx.stage.Stage;
  12.  
  13. public class Main extends Application {
  14. 	
  15.     public void calculate() {
  16.     	//Here I want to change the "percentage text"
  17.     	//and update the stage.
  18.     }
  19.     
  20.     @Override
  21.     public void start(Stage primaryStage) {
  22.         primaryStage.setTitle("Hello World!");
  23.         
  24.         Text percentage = new Text();
  25.         
  26.         Button btn = new Button();
  27.         btn.setText("Say 'Hello World'");
  28.         btn.setOnAction(new EventHandler<ActionEvent>() {
  29.  
  30.             @Override
  31.             public void handle(ActionEvent event) {
  32.                 calculate();
  33.             }
  34.         });
  35.         
  36.         final GridPane inputGridPane = new GridPane();
  37.         GridPane.setConstraints(btn, 0, 0);
  38.         GridPane.setConstraints(percentage, 1, 0);
  39.         inputGridPane.setHgap(6);
  40.         inputGridPane.setVgap(6);
  41.         inputGridPane.getChildren().addAll(btn, percentage);
  42.         
  43.         final Pane rootGroup = new VBox(12);
  44.         rootGroup.setPrefWidth(400);
  45.         rootGroup.setPrefHeight(225);
  46.         rootGroup.getChildren().addAll(inputGridPane);
  47.         rootGroup.setPadding(new Insets(12,12,12,12));
  48.         
  49.         primaryStage.setScene(new Scene(rootGroup));
  50.         primaryStage.show();
  51.     }
  52.     
  53.     public static void main(String[] args) {
  54.         launch(args);
  55.     }
  56. }

This is what my code roughly looks like. Thank you in advance.

答案1

得分: 0

JavaFx提供了一个名为"Task<v>"的类，可以用于在后台进行计算并保持进度同步！

我建议这样做：

创建一个继承Task<v>的第二个类来执行重计算：

  1. import javafx.concurrent.Task;
  3. public class CalculationTask extends Task&lt;String&gt; {
  4.     @Override
  5.     protected String call() throws Exception {
  6.         for (int i = 0; i &lt; 100000000;i++) {
  7.             updateProgress(i, 100000000);
  8.         }
  10.         succeeded();
  11.         return "这是计算的结果... 如果你在计算数字，数据类型可以通过泛型进行更改";
  12.     }
  13. }

这是在应用程序类中如何使用它的一种方式：

  1. import javafx.application.Application;
  2. import javafx.concurrent.Task;
  3. import javafx.concurrent.WorkerStateEvent;
  4. import javafx.event.ActionEvent;
  5. import javafx.event.EventHandler;
  6. import javafx.geometry.Insets;
  7. import javafx.scene.Scene;
  8. import javafx.scene.control.Alert;
  9. import javafx.scene.control.Button;
  10. import javafx.scene.control.ProgressBar;
  11. import javafx.scene.layout.GridPane;
  12. import javafx.scene.layout.Pane;
  13. import javafx.scene.layout.VBox;
  14. import javafx.stage.Stage;
  16. public class Main extends Application {
  17.     @Override
  18.     public void start(Stage primaryStage) {
  19.         primaryStage.setTitle("Hello World!");
  21.         Button btn = new Button();
  22.         btn.setText("Say 'Hello World'");
  24.         Task&lt;String&gt; calculationTask = new CalculationTask();
  26.         ProgressBar progressBar = new ProgressBar(); //ProgressIndicator could also be used
  27.         progressBar.progressProperty().bind(calculationTask.progressProperty());
  28.         progressBar.visibleProperty().bind(calculationTask.runningProperty());
  30.         btn.setOnAction(new EventHandler&lt;ActionEvent&gt;() {
  31.             @Override
  32.             public void handle(ActionEvent event) {
  33.                 calculationTask.setOnSucceeded(new EventHandler&lt;WorkerStateEvent&gt;() {
  34.                     @Override
  35.                     public void handle(WorkerStateEvent workerStateEvent) {
  36.                         new Alert(Alert.AlertType.CONFIRMATION, calculationTask.getValue()).show();
  37.                     }
  38.                 });
  39.                 new Thread(calculationTask).start();
  40.             }
  41.         });
  43.         final GridPane inputGridPane = new GridPane();
  44.         GridPane.setConstraints(btn, 0, 0);
  45.         GridPane.setConstraints(progressBar, 1, 0);
  46.         inputGridPane.setHgap(6);
  47.         inputGridPane.setVgap(6);
  48.         inputGridPane.getChildren().addAll(btn, progressBar);
  50.         final Pane rootGroup = new VBox(12);
  51.         rootGroup.setPrefWidth(400);
  52.         rootGroup.setPrefHeight(225);
  53.         rootGroup.getChildren().addAll(inputGridPane);
  54.         rootGroup.setPadding(new Insets(12,12,12,12));
  56.         primaryStage.setScene(new Scene(rootGroup));
  57.         primaryStage.show();
  58.     }
  60.     public static void main(String[] args) {
  61.         launch(args);
  62.     }
  63. }

希望这有所帮助，否则请随时提问！

英文:

JavaFx provides a class called "Task<v>" which can be used for background calculations while keeping the progression syncronised!

I would suggest doing it that way:

Create a second class extending Task<v> for doing the heavy calculation:

  1. import javafx.concurrent.Task;
  2. public class CalculationTask extends Task&lt;String&gt; {
  3. @Override
  4. protected String call() throws Exception {
  5. for (int i = 0; i &lt; 100000000;i++) {
  6. updateProgress(i, 100000000);
  7. }
  8. succeeded();
  9. return &quot;This is the computed result... Datatype can be changed by generics if you are calculation numbers&quot;;
  10. }
  11. }

This is one way how you could use it in your application class:

  1. import javafx.application.Application;
  2. import javafx.concurrent.Task;
  3. import javafx.concurrent.WorkerStateEvent;
  4. import javafx.event.ActionEvent;
  5. import javafx.event.EventHandler;
  6. import javafx.geometry.Insets;
  7. import javafx.scene.Scene;
  8. import javafx.scene.control.Alert;
  9. import javafx.scene.control.Button;
  10. import javafx.scene.control.Dialog;
  11. import javafx.scene.control.ProgressBar;
  12. import javafx.scene.layout.GridPane;
  13. import javafx.scene.layout.Pane;
  14. import javafx.scene.layout.VBox;
  15. import javafx.scene.text.Text;
  16. import javafx.stage.Stage;
  17. public class Main extends Application {
  18. @Override
  19. public void start(Stage primaryStage) {
  20. primaryStage.setTitle(&quot;Hello World!&quot;);
  21. Button btn = new Button();
  22. btn.setText(&quot;Say &#39;Hello World&#39;&quot;);
  23. Task&lt;String&gt; calculationTask = new CalculationTask();
  24. ProgressBar progressBar = new ProgressBar(); //ProgressIndicator could also be used
  25. progressBar.progressProperty().bind(calculationTask.progressProperty());
  26. progressBar.visibleProperty().bind(calculationTask.runningProperty());
  27. btn.setOnAction(new EventHandler&lt;ActionEvent&gt;() {
  28. @Override
  29. public void handle(ActionEvent event) {
  30. calculationTask.setOnSucceeded(new EventHandler&lt;WorkerStateEvent&gt;() {
  31. @Override
  32. public void handle(WorkerStateEvent workerStateEvent) {
  33. new Alert(Alert.AlertType.CONFIRMATION, calculationTask.getValue()).show();
  34. }
  35. });
  36. new Thread(calculationTask).start();
  37. }
  38. });
  39. final GridPane inputGridPane = new GridPane();
  40. GridPane.setConstraints(btn, 0, 0);
  41. GridPane.setConstraints(progressBar, 1, 0);
  42. inputGridPane.setHgap(6);
  43. inputGridPane.setVgap(6);
  44. inputGridPane.getChildren().addAll(btn, progressBar);
  45. final Pane rootGroup = new VBox(12);
  46. rootGroup.setPrefWidth(400);
  47. rootGroup.setPrefHeight(225);
  48. rootGroup.getChildren().addAll(inputGridPane);
  49. rootGroup.setPadding(new Insets(12,12,12,12));
  50. primaryStage.setScene(new Scene(rootGroup));
  51. primaryStage.show();
  52. }
  53. public static void main(String[] args) {
  54. launch(args);
  55. }
  56. }

I hope that helped, otherwise feel free to ask questions!

huangapple
  • 本文由 发表于 2020年7月22日 17:25:46
  • 转载请务必保留本文链接：https://go.coder-hub.com/63031026.html
  • java
  • javafx
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