从另一个线程扩展类更新 UI

Question

What I want to do:

[Web Scraping with Jsoup]

Adding elements to a TableView from an another Thread extended Class.

Button click -> start Thread -> Thread add elements to TableView.

Files

|javafxapplication5
|-->FXMLDocuments.fxml
|-->FXMLDocumentController.java
|-->JavaFXApplication5.java
|-->Scraper.java

FXMLDocumentController.java

package javafxapplication5;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.input.MouseEvent;


public class FXMLDocumentController implements Initializable {
    Scraper scraper = new Scraper();
    
    @FXML
    private Label label;
    
    @FXML
    private Button shareButton;
    
    @FXML
    private TextField searchInput;

    @FXML
    private Button searchTorrents;

    @FXML
    private void handleButtonAction(ActionEvent event) {
        System.out.println("You clicked me!");
    }
    
    @FXML
    private void setMouseEntered(MouseEvent event)
    {
        searchTorrents.setStyle("-fx-border-color:blue");
    }
    @FXML
    private void setMouseLeaved(MouseEvent event)
    {
        searchTorrents.setStyle("-fx-border-color:black");
    }
    
    @FXML
    private void shareButton(ActionEvent event)
    {
        Alert alert = new Alert(Alert.AlertType.INFORMATION);
        alert.setHeaderText("Hai cliccato il bottone share");
        alert.showAndWait();
    }
    
    @FXML
    private void scrapButton(ActionEvent event)
    {
        scraper.start();
    }
     
    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    
    
}

Scraper.java

package javafxapplication5;

import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;


public class Scraper extends Thread{
    public void run()
    {
        Document doc;
        try {
            doc = Jsoup.connect("https://www.allkeyshop.com/blog/daily-deals/").get();
            Elements gamesNames = doc.select(".search-results-row-game-title");
            for (Element element:gamesNames)
            {
                //Update TableView
            }
        } catch (IOException ex) {
            Logger.getLogger(TorrentScraper.class.getName()).log(Level.SEVERE, null, ex);
        }
    }
}

I hope is everything clear, if not please answer me with a constructive suggestion.

Answer 1

Here is an example you can use as a guide. The URL you use does not have a result list. I would suggest you use something like https://www.allkeyshop.com/blog/catalogue/search-game/ . It appears, what comes after the hyphen is what is being searched. You may need to do a few complicated searches to see how the URL changes.

This example uses Task . In the Task setOnSuccedded updates the TableView .

Main

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.concurrent.Task;
import javafx.concurrent.WorkerStateEvent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

/**
 * JavaFX App
 */
public class App extends Application
{

    @Override
    public void start(Stage primaryStage)
    {
        TableView<JSoupData> tvMain = new TableView();
        ObservableList<JSoupData> tableItems = FXCollections.observableArrayList();
        tvMain.setItems(tableItems);

        TableColumn<JSoupData, String> tcTagName = new TableColumn<>("Tag Name");
        tcTagName.setCellValueFactory(new PropertyValueFactory<>("tagName"));
        TableColumn<JSoupData, String> tcText = new TableColumn<>("Text");
        tcText.setCellValueFactory(new PropertyValueFactory<>("text"));
        tvMain.getColumns().add(tcTagName);
        tvMain.getColumns().add(tcText);

        TextField tfUrl = new TextField("https://www.allkeyshop.com/blog/catalogue/search-game/");
        tfUrl.setPromptText("Enter URL Here!");

        Button btnProcess = new Button("Process URL");
        btnProcess.setOnAction((t) -> {
            btnProcess.setDisable(true);

            Task<List<JSoupData>> task = scrapper(tfUrl.getText());
            task.setOnSucceeded((WorkerStateEvent t1) -> {
                List<JSoupData> tempList = task.getValue();
                tableItems.setAll(tempList);
                btnProcess.setDisable(false);
            });
            Thread thread = new Thread(task);
            thread.setDaemon(true);
            thread.start();
        });
        VBox root = new VBox(tvMain, tfUrl, btnProcess);

        Scene scene = new Scene(root);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

    public Task<List<JSoupData>> scrapper(String url)
    {
        Task<List<JSoupData>> scrapperTask = new Task<List<JSoupData>>()
        {
            @Override
            protected List<JSoupData> call()
            {
                List<JSoupData> jSoupDatas = new ArrayList();
                try {
                    System.out.println("url: " + url);
                    Document document = Jsoup.connect(url).get();
                    System.out.println("Title: " + document.title());
                    Elements gamesNames = document.select(".search-results-row");
                    System.out.println("search-results-row");
                    for (Element element : gamesNames) {
                        jSoupDatas.add(new JSoupData(element.tagName(), element.text()));
                        System.out.println("Tag Name: " + element.tagName() + " - Text: " + element.text());
                    }
                }
                catch (IOException e) {
                    System.out.println(e.toString());
                }

                return jSoupDatas;
            }
        };

        return scrapperTask;
    }
}

JSoupData

 *
 * @author sedrick (sedj601)
 */
public class JSoupData
{

    private String tagName;
    private String text;

    public JSoupData(String tagName, String text)
    {
        this.tagName = tagName;
        this.text = text;
    }

    public String getText()
    {
        return text;
    }

    public void setText(String text)
    {
        this.text = text;
    }

    public String getTagName()
    {
        return tagName;
    }

    public void setTagName(String tagName)
    {
        this.tagName = tagName;
    }

    @Override
    public String toString()
    {
        StringBuilder sb = new StringBuilder();
        sb.append("JSoupData{tagName=").append(tagName);
        sb.append(", text=").append(text);
        sb.append('}');
        return sb.toString();
    }
}

Answer 2

Usually, Platform.runLater() can be used to execute those updates on the JavaFX application thread.

You can get more information from documentation here and an example from here