multithreading - Javafx 几个 GUI 线程 - 进度指示器

Question

在 javafx 中，GUI 进程是在单独的线程上完成的。不允许将进度指示器放在具有服务和任务的后台线程上，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？

或者是否有另一种方法可以在加载其他 gui 元素时使进度指示器继续滚动？目前它开始滚动，然后卡住，直到加载 Pane 。

@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

不确定进度指标

progress indicator keep rolling

我认为你的意思是 indeterminate progress indicator .

默认情况下，进度指示器以不确定状态启动，您可以随时通过将其进度设置为不确定来将指示器更改回不确定状态:

progressIndicator.setProgress(ProgressIndicator.INDETERMINATE);

不确定的进度指标和任务

由于进度默认是不确定的，如果您在任务完成之前不更新任务进度，则在任务运行时绑定(bind)到任务进度的进度指示器将保持不确定状态。

示例

此示例中的进度指示器只是一组旋转点，指示任务完成之前的不确定进度。

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);
    }
}