JavaFX表行更新

时间:2018-09-26 13:55:56

标签: java javafx

我要实现的方案是

  1. 只要TableCell中的特定TableRow得到更新,行颜色将变为红色,并且3秒钟后,该颜色应自动恢复为原始颜色。

以下是 MCVE

主班

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.stage.Stage;

public class TestProjectWin10 extends Application {
    private final ObservableList<Element> data = FXCollections.observableArrayList();

    public final Runnable changeValues = () -> {
        int i = 0;
        while (i <= 100000) {
            if (Thread.currentThread().isInterrupted()) {
                break;
            }
            data.get(0).setOccurence(System.currentTimeMillis());
            data.get(0).count();
            i = i + 1;
        }
    };

    private final ExecutorService executor = Executors.newSingleThreadExecutor(runnable -> {
        Thread t = new Thread(runnable);
        t.setDaemon(true);
        return t;
    });

    @Override
    public void start(Stage primaryStage) {

        TableView<Element> table = new TableView<>();
        table.getStylesheets().add(this.getClass().getResource("tableColor.css").toExternalForm());
        table.setEditable(true);

        TableColumn<Element, String> nameCol = new TableColumn<>("Name");
        nameCol.setPrefWidth(200);
        nameCol.setCellValueFactory(cell -> cell.getValue().nameProperty());
        nameCol.setCellFactory((TableColumn<Element, String> param) -> new ColorCounterTableCellRenderer(table));
        table.getColumns().add(nameCol);

        this.data.add(new Element());
        table.setItems(this.data);

        this.executor.submit(this.changeValues);

        Scene scene = new Scene(table, 600, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

元素类:

import java.util.concurrent.atomic.AtomicReference;

import javafx.application.Platform;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;

public class Element {
    int x = 0;

    private final StringProperty nameProperty = new SimpleStringProperty("");

    private final AtomicReference<String> name = new AtomicReference<>();

    private final DoubleProperty occurence = new SimpleDoubleProperty();

    public void count() {
        x = x + 1;
        if (name.getAndSet(Integer.toString(x)) == null) {
            Platform.runLater(() -> nameProperty.set(name.getAndSet(null)));
        }
    }

    public void setOccurence(double value) {
        occurence.set(value);
    }

    public String getName() {
        return nameProperty().get();
    }

    public void setName(String name) {
        nameProperty().set(name);
    }

    public StringProperty nameProperty() {
        return nameProperty;
    }

    double getOccurrenceTime() {
        return occurence.get();
    }
}

CellFactory代码:

import java.util.Timer;
import java.util.TimerTask;
import javafx.application.Platform;
import javafx.geometry.Pos;
import javafx.scene.control.TableCell;
import javafx.scene.control.TableRow;
import javafx.scene.control.TableView;

public class ColorCounterTableCellRenderer extends TableCell<Element, String> {

    private final static long MAX_MARKED_TIME = 3000;
    private final static long UPDATE_INTERVAL = 1000;

    private static Timer t = null;
    private final String highlightedStyle = "highlightedRow";

    private final TableView tv;

    public ColorCounterTableCellRenderer(TableView tv) {
        this.tv = tv;
        createTimer();
        setAlignment(Pos.CENTER_RIGHT);
    }

    private void createTimer() {
        if (t == null) {
            t = new Timer("Hightlight", true);
            t.schedule(new TimerTask() {
                @Override
                public void run() {

                    final long currentTime = System.currentTimeMillis();

                    TableRow tr = getTableRow();
                    if (tr.getItem() != null) {

                        if (currentTime - ((Element) tr.getItem()).getOccurrenceTime() > MAX_MARKED_TIME) {
                            Platform.runLater(() -> {
                                tr.getStyleClass().remove(highlightedStyle);
                            });
                        }
                    }
                }
            }, 0, UPDATE_INTERVAL);
        }
    }

    @Override
    protected void updateItem(String item, boolean empty) {
        if (empty || getTableRow() == null || getTableRow().getItem() == null) {
            setText(null);
            return;
        }

        long currentTime = System.currentTimeMillis();

        TableRow<Element> row = getTableRow();
        Element elementRow = row.getItem();

        double occurrenceTime = elementRow.getOccurrenceTime();

        if (currentTime - occurrenceTime < MAX_MARKED_TIME) {
            if (!row.getStyleClass().contains(highlightedStyle)) {
                row.getStyleClass().add(highlightedStyle);
            }
        }

        super.updateItem(item, empty);
        setText(item + "");

    }
}

和CSS文件tableColor.css

.highlightedRow {
    -fx-background-color: rgba(255,0,0, 0.25);
    -fx-background-insets: 0, 1, 2;
    -fx-background: -fx-accent;
    -fx-text-fill: -fx-selection-bar-text;    
}

出了什么问题..?

  1. 我检查当前时间与更新发生时间之间的差异是否小于3秒-行颜色变为红色(在ColorCounterTableCellRenderer-updateItem方法中)

  2. 在一个单独的计时器(ColorCounterTableCellRenderer)中,我尝试检查当前时间与更新发生时间之间的时差是否超过3秒-消除红色。

但是在计时器(createTimer-方法)代码中:tr.getItem()始终为null,因此不会消除红色。

这是实现我想要的正确方法吗?为什么tr.getItem()返回null

要测试:我运行了代码,等待executor代码结束,并检查了3秒后是否去除了红色。

2 个答案:

答案 0 :(得分:5)

对UI的任何更新,即使它是通过侦听器触发的,也都需要在应用程序线程中完成。 (您可以通过使用Platform.runLater进行更新来解决此问题。)

此外,您不能依靠相同的单元格在应该显示为已标记的完整时间内保持相同的单元格。

要解决此问题,您需要将有关标记单​​元格的信息存储在项目本身或某些可观察到的外部数据结构中。

以下示例将上次更新时间存储在ObservableMap中,并使用AnimationTimer从映射中清除过期的条目。此外,它使用TableRow来根据地图的内容更新伪类。

private static class Item {

    private final IntegerProperty value = new SimpleIntegerProperty();
}

private final ObservableMap<Item, Long> markTimes = FXCollections.observableHashMap();
private AnimationTimer updater;

private void updateValue(Item item, int newValue) {
    int oldValue = item.value.get();
    if (newValue != oldValue) {
        item.value.set(newValue);

        // update time of item being marked
        markTimes.put(item, System.nanoTime());

        // timer for removal of entry
        updater.start();
    }
}

@Override
public void start(Stage primaryStage) {
    Item item = new Item(); // the item that is updated
    TableView<Item> table = new TableView<>();
    table.getItems().add(item);

    // some additional items to make sure scrolling effects can be tested
    IntStream.range(0, 100).mapToObj(i -> new Item()).forEach(table.getItems()::add);

    TableColumn<Item, Number> column = new TableColumn<>();
    column.getStyleClass().add("mark-column");
    column.setCellValueFactory(cd -> cd.getValue().value);
    table.getColumns().add(column);

    final PseudoClass marked = PseudoClass.getPseudoClass("marked");

    table.setRowFactory(tv -> new TableRow<Item>() {

        final InvalidationListener reference = o -> {
            pseudoClassStateChanged(marked, !isEmpty() && markTimes.containsKey(getItem()));
        };
        final WeakInvalidationListener listener = new WeakInvalidationListener(reference);

        @Override
        protected void updateItem(Item item, boolean empty) {
            boolean wasEmpty = isEmpty();
            super.updateItem(item, empty);

            if (empty != wasEmpty) {
                if (empty) {
                    markTimes.removeListener(listener);
                } else {
                    markTimes.addListener(listener);
                }
            }

            reference.invalidated(null);
        }

    });

    Scene scene = new Scene(table);
    scene.getStylesheets().add("style.css");
    primaryStage.setScene(scene);
    primaryStage.show();

    updater = new AnimationTimer() {

        @Override
        public void handle(long now) {
            for (Iterator<Map.Entry<Item, Long>> iter = markTimes.entrySet().iterator(); iter.hasNext();) {
                Map.Entry<Item, Long> entry = iter.next();

                if (now - entry.getValue() > 2_000_000_000L) { // remove after 1 sec
                    iter.remove();
                }
            }

            // pause updates, if there are no entries left
            if (markTimes.isEmpty()) {
                stop();
            }
        }
    };

    final Random random = new Random();

    Thread t = new Thread(() -> {

        while (true) {
            try {
                Thread.sleep(4000);
            } catch (InterruptedException ex) {
                continue;
            }
            Platform.runLater(() -> {
                updateValue(item, random.nextInt(4));
            });
        }
    });
    t.setDaemon(true);
    t.start();
}

style.css

.table-row-cell:marked .table-cell.mark-column {
    -fx-background-color: red;
}

答案 1 :(得分:-1)

我同意@kleopatra的评论。您不能在单元内进行复杂的数据处理。通常,您的Row / Cell / updateItem()应该更多地关注“呈现方式/呈现方式”。我可以为您提供一些可供参考的关键指导。

如果要更新行样式,则基于项的某些更新(不是由于添加/删除项,而是由于项的属性内的更新),您必须首先侦听更改。

仅在ObservableList上设置ListChangeListener不会通知您“内部”属性发生的任何更改。您必须使用您感兴趣的属性注册ObservableList,并且在更新时需要通知这些属性。 因此,应该在TableView中设置的ObservableList应该注册/声明如下:

    ObservableList<Person> persons = FXCollections.observableArrayList(e -> 
                                                      new Observable[]{e.pointsProperty()});

以上代码在点属性更新时强制触发ObservableList的ListChangeListener。从那里您可以执行所需的操作。

以下是一个快速工作的演示,它在每次更新“点”列时突出显示该行3秒。我希望这个演示可以给您一些输入来解决您的问题。这种方法之一。可以有更多更好的方法来实现以下功能。您仍然可以使用@fabian解决方案。

注意: 使用与您提供的相同的css文件。

import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.Observable;
import javafx.beans.property.*;
import javafx.collections.FXCollections;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableRow;
import javafx.scene.control.TableView;
import javafx.stage.Stage;
import javafx.util.Callback;
import javafx.util.Duration;
import java.security.SecureRandom;

public class TableRowUpdateHighlightDemo extends Application {
    private final SecureRandom rnd = new SecureRandom();

    @Override
    public void start(Stage primaryStage) throws Exception {
        ObservableList<Person> persons = FXCollections.observableArrayList(e -> new Observable[]{e.pointsProperty()});
        persons.add(new Person("Harry", "John"));
        persons.add(new Person("Mary", "King"));
        persons.add(new Person("Don", "Bon"));
        persons.add(new Person("Pink", "Wink"));

        TableView<Person> tableView = new TableView<>();
        TableColumn<Person, String> fnCol = new TableColumn<>("First Name");
        fnCol.setCellValueFactory(param -> param.getValue().firstNameProperty());

        TableColumn<Person, String> lnCol = new TableColumn<>("Last Name");
        lnCol.setCellValueFactory(param -> param.getValue().lastNameProperty());

        TableColumn<Person, Integer> pointsCol = new TableColumn<>("Points");
        pointsCol.setCellValueFactory(param -> param.getValue().pointsProperty().asObject());

        tableView.getStylesheets().add(this.getClass().getResource("tableColor.css").toExternalForm());
        tableView.getColumns().addAll(fnCol, lnCol, pointsCol);
        tableView.setItems(persons);
        tableView.getItems().addListener((ListChangeListener<Person>) c -> {
            if (c.next()) {
                if (c.wasUpdated()) {
                    tableView.getItems().get(c.getFrom()).setHightlight(true);
                    tableView.refresh();
                }
            }
        });
        tableView.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);

        tableView.setRowFactory(new Callback<TableView<Person>, TableRow<Person>>() {
            @Override
            public TableRow<Person> call(TableView<Person> param) {
                return new TableRow<Person>() {
                    Timeline highlightTL;

                    @Override
                    protected void updateItem(Person item, boolean empty) {
                        super.updateItem(item, empty);
                        removeHighlight();
                        if (item != null && item.isHightlight()) {
                            getStyleClass().add("highlightedRow");
                            getHighlightTL().playFromStart();
                        }
                    }

                    private void removeHighlight() {
                        getHighlightTL().stop();
                        getStyleClass().removeAll("highlightedRow");
                    }

                    private Timeline getHighlightTL() {
                        if (highlightTL == null) {
                            // After 3 secs, the hightlight will be removed.
                            highlightTL = new Timeline(new KeyFrame(Duration.millis(3000), e -> {
                                getItem().setHightlight(false);
                                removeHighlight();
                            }));
                            highlightTL.setCycleCount(1);
                        }
                        return highlightTL;
                    }
                };
            }
        });

        Scene sc = new Scene(tableView);
        primaryStage.setScene(sc);
        primaryStage.show();

        // Updating points every 5 secs to a random person.
        Timeline tl = new Timeline(new KeyFrame(Duration.millis(5000), e -> {
            Person p = persons.get(rnd.nextInt(4));
            p.setPoints(p.getPoints() + 1);
        }));
        tl.setCycleCount(Animation.INDEFINITE);
        tl.play();

    }

    class Person {
        private StringProperty firstName = new SimpleStringProperty();
        private StringProperty lastName = new SimpleStringProperty();
        private IntegerProperty points = new SimpleIntegerProperty();
        private BooleanProperty hightlight = new SimpleBooleanProperty();

        public Person(String fn, String ln) {
            setFirstName(fn);
            setLastName(ln);
        }

        public String getFirstName() {
            return firstName.get();
        }

        public StringProperty firstNameProperty() {
            return firstName;
        }

        public void setFirstName(String firstName) {
            this.firstName.set(firstName);
        }

        public String getLastName() {
            return lastName.get();
        }

        public StringProperty lastNameProperty() {
            return lastName;
        }

        public void setLastName(String lastName) {
            this.lastName.set(lastName);
        }

        public int getPoints() {
            return points.get();
        }

        public IntegerProperty pointsProperty() {
            return points;
        }

        public void setPoints(int points) {
            this.points.set(points);
        }

        public boolean isHightlight() {
            return hightlight.get();
        }

        public BooleanProperty hightlightProperty() {
            return hightlight;
        }

        public void setHightlight(boolean hightlight) {
            this.hightlight.set(hightlight);
        }
    }
}

更新:: :如果可以在外部(3秒后)更新“ hightlight”属性值,则RowFactory中不需要时间轴。只需在ListChangeListener中调用tableView.refresh()即可:)