为什么我的视频时间轴不起作用？

Question

I'm trying to make a video timeline, with a slider (change which sec appear on the screen) but it doesn't work. My problem is, the method above is not working. I really don't know why, I saw this code working in many tutorials but I can't use.

The error message is: "no suitable method found addListener"

This is the problematic method:

mediaPlayer.currentTimeProperty().addListener(new ChangeListener<Duration>() {
                @Override
                public void changed(ObservableValue<? extends Duration> observable, Duration oldValue, Duration newValue) {
                    seekSlider.setValue(newValue.getSeconds());
                }
            });

package amedia;

import java.io.File;
import java.net.URL;
import java.time.Duration;
import java.util.ResourceBundle;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.beans.binding.Bindings;
import javafx.beans.property.DoubleProperty;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.control.Slider;
import javafx.scene.media.Media;
import javafx.scene.media.MediaPlayer;
import javafx.scene.media.MediaView;
import javafx.stage.FileChooser;

public class FXMLDocumentController implements Initializable {

    private MediaPlayer mediaPlayer;


    private String filePath;

    @FXML
    private Label label;

    @FXML
    private MediaView mediaView;

    @FXML
    private Slider slider;

    @FXML
    private Slider seekSlider;

    @FXML
    private void handleButtonAction(ActionEvent event) {
        FileChooser fileChooser = new FileChooser();
        FileChooser.ExtensionFilter filter = new FileChooser.ExtensionFilter("Select a file (*.mp4)", "*.mp4");
        fileChooser.getExtensionFilters().add(filter);
        File file = fileChooser.showOpenDialog(null);
        filePath = file.toURI().toString();

        if (filePath != null) {
            Media media = new Media(filePath);
            mediaPlayer = new MediaPlayer(media);
            mediaView.setMediaPlayer(mediaPlayer);

            DoubleProperty width = mediaView.fitWidthProperty();
            DoubleProperty height = mediaView.fitHeightProperty();

            width.bind(Bindings.selectDouble(mediaView.sceneProperty(), "width"));
            height.bind(Bindings.selectDouble(mediaView.sceneProperty(), "height"));

            slider.setValue(mediaPlayer.getVolume() * 100);

            slider.valueProperty().addListener(new InvalidationListener() {
                @Override
                public void invalidated(Observable observable) {
                    mediaPlayer.setVolume(slider.getValue()/100);     
                }
            });

            mediaPlayer.currentTimeProperty().addListener(new ChangeListener<Duration>() {
                @Override
                public void changed(ObservableValue<? extends Duration> observable, Duration oldValue, Duration newValue) {
                    seekSlider.setValue(newValue.getSeconds());
                }
            });

            mediaPlayer.play();
        }

    }

    @FXML
    private void pauseVideo(ActionEvent event) {
        mediaPlayer.pause();
    }

    @FXML
    private void playVideo(ActionEvent event) {
        mediaPlayer.play();
        mediaPlayer.setRate(1.0);
    }
    @FXML
    private void stopVideo(ActionEvent event) {
        mediaPlayer.stop();
    }
    @FXML
    private void fastVideo(ActionEvent event) {
        mediaPlayer.setRate(1.5);
    }
    @FXML
    private void fasterVideo(ActionEvent event) {
        mediaPlayer.setRate(2.5);
    }
    @FXML
    private void slowVideo(ActionEvent event) {
        mediaPlayer.setRate(0.75);
    }
    @FXML
    private void slowerVideo(ActionEvent event) {
        mediaPlayer.setRate(0.5);
    }
    @FXML
    private void exit(ActionEvent event) {
        System.exit(0);
    }

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    } 

}

Answer 1

You have imported the wrong Duration class:

import java.time.Duration;

You need to import the JavaFX Duration class instead:

import javafx.util.Duration;