我正在使用Javafx，在使用后台任务进行更新时，我正在努力获得一个已排序的表。在代码here中，可以独立运行，我在后台更新表。
我想要做的是这个表格会更新，并按时间顺序排列，因此较旧的列车时间显示在顶部，后面的列车显示在底部。该示例生成的时间与目的相反，以查看排序是否有效。
在我向表中添加并发更新之前，我运行了一些测试，我这样做的方法是调用：
private final ObservableList<StationBoardLine> data = FXCollections.observableArrayList(
new StationBoardLine("RE", "17:14", "Basel Bad Bf", "Basel SBB", "+3", "RE 5343"));
SortedList<StationBoardLine> sorted = new SortedList<>(data, new DelayComparator());
table.setItems(sorted);
但是，现在我没有设置项目，而是将后台任务与ReadOnlyObjectProperty和ReadOnlyObjectWrapper一起添加到其中。
所以，我的问题是，如何确保添加项目时，列表仍然有序？我试着看看我是否可以在调用Platform.runLater的内容中对列表进行重新排序，但似乎没有用。
更新表和表的任务之间的链接如下：
table.itemsProperty().bind(task.partialResultsProperty());
感谢您的帮助，
盖尔德
答案 0 :(得分：1)
我这样做的方法是通过后台任务更新ObservableList并将其用作＆＃34;源＆＃34;创建SortedList。然后，这个SortedList将作为＆＃34; items＆＃34;的来源。到TableView。
一般结构是：
public class MyClass {
private TableView<T> tableView = new TableView;
private ObservableList<T> sourceList = FXCollections.observableArrayList();
public MyClass() {
...
SortedList<T> sortedList = new SortedList<>(sourceList, new MyComparator());
tableView.setItems(sortedList);
...
new Task<Void> {
protected Void call() {
... // Some background data fetch
Platform.runLater(() -> sourceList.add(data));
return null;
}
};
}
}
对于你的场景，我会选择你已有的东西。因此，我将使用Task#getPartialResults()返回的列表，而不是创建一个新的ObservableList作为SortedList的源。
DelayComparator使用延迟值来比较和显示TableView中的数据。
import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.property.SimpleStringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.SortedList;
import javafx.concurrent.Task;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import java.util.Comparator;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class App extends Application {
private TableView<StationBoardLine> table = new TableView<>();
private final ExecutorService exec = Executors.newSingleThreadExecutor();
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage) {
BorderPane root = new BorderPane();
Scene scene = new Scene(root, 800, 600);
table.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY);
table.setEditable(true);
TableColumn typeCol = getTableCol("Type", 10, "type");
TableColumn departureCol = getTableCol("Departure", 30, "departure");
TableColumn stationCol = getTableCol("Station", 200, "station");
TableColumn destinationCol = getTableCol("Destination", 200, "destination");
TableColumn delayCol = getTableCol("Delay", 20, "delay");
TableColumn trainName = getTableCol("Train Name", 50, "trainName");
table.getColumns().addAll(
typeCol, departureCol, stationCol, destinationCol, delayCol, trainName);
root.setCenter(table);
PartialResultsTask task = new PartialResultsTask();
SortedList<StationBoardLine> sorted = new SortedList<>(task.getPartialResults(), new DelayComparator());
table.setItems(sorted);
exec.submit(task);
stage.setTitle("Swiss Transport Delays Board");
stage.setScene(scene);
stage.show();
}
private TableColumn getTableCol(String colName, int minWidth, String fieldName) {
TableColumn<StationBoardLine, String> typeCol = new TableColumn<>(colName);
typeCol.setMinWidth(minWidth);
typeCol.setCellValueFactory(new PropertyValueFactory<>(fieldName));
return typeCol;
}
static final class DelayComparator implements Comparator<StationBoardLine> {
@Override
public int compare(StationBoardLine o1, StationBoardLine o2) {
return o1.getDelay().compareTo(o2.getDelay());
}
}
public class PartialResultsTask extends Task<Void> {
private ObservableList<StationBoardLine>partialResults = FXCollections.observableArrayList();
public final ObservableList<StationBoardLine> getPartialResults() {
return partialResults;
}
@Override protected Void call() throws Exception {
System.out.println("Creating station board entries...");
for (int i=5; i >= 1; i--) {
Thread.sleep(1000);
if (isCancelled()) break;
StationBoardLine l = new StationBoardLine(
"ICE", "16:" + i, "Basel Bad Bf", "Chur", String.valueOf(i), "ICE 75");
Platform.runLater(() -> partialResults.add(l));
}
return null;
}
}
public static final class StationBoardLine {
private final SimpleStringProperty type;
private final SimpleStringProperty departure;
private final SimpleStringProperty station;
private final SimpleStringProperty destination;
private final SimpleStringProperty delay;
private final SimpleStringProperty trainName;
StationBoardLine(String type,
String departure,
String station,
String destination,
String delay,
String trainName) {
this.type = new SimpleStringProperty(type);
this.departure = new SimpleStringProperty(departure);
this.station = new SimpleStringProperty(station);
this.destination = new SimpleStringProperty(destination);
this.delay = new SimpleStringProperty(delay);
this.trainName = new SimpleStringProperty(trainName);
}
public String getType() {
return type.get();
}
public SimpleStringProperty typeProperty() {
return type;
}
public void setType(String type) {
this.type.set(type);
}
public String getDeparture() {
return departure.get();
}
public SimpleStringProperty departureProperty() {
return departure;
}
public void setDeparture(String departure) {
this.departure.set(departure);
}
public String getStation() {
return station.get();
}
public SimpleStringProperty stationProperty() {
return station;
}
public void setStation(String station) {
this.station.set(station);
}
public String getDestination() {
return destination.get();
}
public SimpleStringProperty destinationProperty() {
return destination;
}
public void setDestination(String destination) {
this.destination.set(destination);
}
public String getDelay() {
return delay.get();
}
public SimpleStringProperty delayProperty() {
return delay;
}
public void setDelay(String delay) {
this.delay.set(delay);
}
public String getTrainName() {
return trainName.get();
}
public SimpleStringProperty trainNameProperty() {
return trainName;
}
public void setTrainName(String trainName) {
this.trainName.set(trainName);
}
}
}