Process listening

Sometimes, when you read a larger pdf document (maybe from a URL), it takes a little bit more time to read it than usuall. That's why this library offers a tool called ProcessListener to show something to the user while the reading of the pdf document is processing.

This tool called ProcessListener is a functional interface. It can take one boolean parameter which is true if the process is finished or false if the process is not finished yet.

You can set the ProcessListener of the PDFDisplayer with the setProcessListener method.

  PDFDisplayer pDisplayer = new PDFDisplayer();
  pdDisplayer.setProcessListener(finished -> {
      if (finished){
          //your code here
      } else {
          //your code here
      }
  });

If you want to execute javaFX tasks in the ProcessListener you have to use the Platform.runLater() method to be sure that you are execute that tasks on the javaFX Application Thread.

  pdDisplayer.setProcessListener(finished -> {
            Platform.runLater(() -> {
                if (finished) {
                    //your code here
                } else {
                    //your code here
                }
            });
        });

Full example

import com.dansoftware.pdfdisplayer.PDFDisplayer;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ProgressBar;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import java.io.IOException;
import java.net.URL;

public class ProcessListenerDemo extends Application {
    @Override
    public void start(Stage primaryStage) throws Exception {

        //create a progressBar
        ProgressBar progressBar = new ProgressBar();
        progressBar.setPrefWidth(500);
        progressBar.setProgress(0);

        //create a pdfDisplayer
        PDFDisplayer pdfDisplayer = new PDFDisplayer();
        //set the process listener of it 
        pdfDisplayer.setProcessListener(finished -> 
            Platform.runLater(() -> {
                if (finished) {
                    //when the process finished
                    progressBar.setProgress(0);
                } else {
                    //when the process started
                    progressBar.setProgress(Timeline.INDEFINITE);
                }
            })
        );

        //create a btn for loading the pdf
        Button loaderBtn = new Button("Load");
        loaderBtn.setOnAction(e ->
            //start a new thread for load the pdf document    
            new Thread(() -> {
                try {
                    pdfDisplayer.displayPdf(new URL("https://www.tutorialspoint.com/javafx/javafx_tutorial.pdf"));
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }).start()
        );

        primaryStage.setScene(new Scene(new VBox(new StackPane(loaderBtn), pdfDisplayer.toNode(), new StackPane(progressBar))));
        primaryStage.show();
    }

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

Result: