Javafx 几个 GUI 线程 - 进度指示器

Question

在 javafx 中，gui 进程在单独的线程上完成。不允许将进度指示器放在带有 Service 和 Task 的后台线程上，因为它不是 FX 线程并且指示器是 FX 元素。是否可以在 javafx 中创建多个 gui 线程？

或者在加载其他 gui 元素时，是否有其他方法可以让进度指示器保持滚动？目前它开始滚动，然后卡住，直到加载窗格。

@FXML
public void budgetShow(ActionEvent event) {
    progressIndicator = new ProgressIndicator(-1.0);
    rootPane.getChildren().add(progressIndicator);
    progressIndicator.setVisible(true);
    progressIndicator.toFront();

    threadBudgetShow().start();
}

public Service<Void> threadBudgetShow() {
Service<Void> service = new Service<Void>() {
    @Override
    protected Task<Void> createTask() {
        return new Task<Void>() {
            @Override
            protected Void call() throws Exception {

                // Background Thread operations.                    
                final CountDownLatch latch = new CountDownLatch(1);

                Platform.runLater(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            // FX Thread opeartions.
                            // budgetAnchorPane - reload.
                            if (budgetAnchorPane == null || !budgetAnchorPane.isVisible()) {
                                budgetAnchorPane = new BudgetAnchorPane();
                                rootPane.getChildren().add(budgetAnchorPane);
                                budgetAnchorPane.setVisible(true);
                                budgetAnchorPane.getChildren().remove(budgetAnchorPane.budgetTypeComboBox);
                                budgetAnchorPane.budgetTypeComboBox = new BudgetTypeCombobox();
                                budgetAnchorPane.getChildren().add(budgetAnchorPane.budgetTypeComboBox);
                            }
                        } finally {
                            rootPane.getChildren().remove(progressIndicator);
                            latch.countDown();
                        }
                    }
                });
                latch.await();
                // Other background Thread operations.
                return null;
            }
        };
    }
};
return service;
}

Answer 1

不确定的进度指标

进度指示器不断滚动

我认为你的意思是indeterminate progress indicator。

默认情况下，进度指示器从不确定状态开始，您可以随时将指示器更改回不确定状态，方法是将其进度设置为不确定：

progressIndicator.setProgress(ProgressIndicator.INDETERMINATE);

不确定的进度指标和任务

由于默认情况下进度是不确定的，如果您在任务完成之前不更新任务的进度，那么绑定到任务进度的进度指示器将在任务运行时保持不确定。

示例

此示例中的进度指示器将只是一组旋转点，指示在任务完成之前不确定的进度。

import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.geometry.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class ProgressTracker extends Application {

    final int N_SECS = 10;

    @Override
    public void start(Stage stage) throws Exception {
        Task task = createTask();

        stage.setScene(
            new Scene(
                createLayout(
                    task
                )
            )
        );
        stage.show();

        new Thread(task).start();
    }

    private Task<Void> createTask() {
        return new Task<Void>() {
            @Override public Void call() {
                for (int i=0; i < N_SECS; i++) {
                    if (isCancelled()) {
                        break;
                    }
                    // uncomment updateProgress call if you want to show progress
                    // rather than let progress remain indeterminate.
                    // updateProgress(i, N_SECS);
                    updateMessage((N_SECS - i) + "");
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        return null;
                    }
                }

                updateMessage(0 + "");
                updateProgress(N_SECS, N_SECS);

                return null;
            }
        };
    }

    private HBox createLayout(Task task) {
        HBox layout = new HBox(10);

        layout.getChildren().setAll(
            createProgressIndicator(task),
            createCounter(task)
        );

        layout.setAlignment(Pos.CENTER_RIGHT);
        layout.setPadding(new Insets(10));

        return layout;
    }

    private ProgressIndicator createProgressIndicator(Task task) {
        ProgressIndicator progress = new ProgressIndicator();

        progress.progressProperty().bind(task.progressProperty());

        return progress;
    }

    private Label createCounter(Task task) {
        Label counter = new Label();

        counter.setMinWidth(20);
        counter.setAlignment(Pos.CENTER_RIGHT);
        counter.textProperty().bind(task.messageProperty());
        counter.setStyle("-fx-border-color: forestgreen;");

        return counter;
    }

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