Question

我不知道为什么会这样。我尝试了所有我能做的但是如果我在start方法中添加do while循环，下面的内容根本无法工作。这没有意义。我的意思是我不会迭代声音（）我也不做任何奇特的事情......只是一个简单的循环阻止我的声音被播放。

为什么？可能是我需要在一个单独的线程中启动音频？如果是，那怎么样？

import java.io.File;

import javafx.application.Application;
import javafx.scene.media.Media;
import javafx.scene.media.MediaPlayer;
import javafx.stage.Stage;

public class SoundTest extends Application{
public static void main(String[] args) {
    launch(args);
}

    @Override
    public void start(Stage arg0) throws Exception {
        sound();
        do {

        }
        while(true);
    }

    public static void sound() {
        String path = "test.mp3";
        Media media = new Media(new File(path).toURI().toString());
        MediaPlayer mediaPlayer = new MediaPlayer(media);
        mediaPlayer.play();
    }
}

Answer 1

您的循环正在阻止JavaFX应用程序线程。在JavaFX中使用任何看起来像游戏循环的东西肯定是错误的并且不起作用。阅读有关JavaFX并发的教程。

Answer 2

您应该熟悉以下Java FX API：

Media
MediaPlayer
MediaView

这将有助于您学习标题为Incorporating Media Assets Into JavaFX Applications的教程主题。

话虽如此，以下SSCCE来自该教程，唯一的修改就是我评论了教程中提供的MEDIA_URL的值，并将其替换为new File("test.mp3").toURI().toASCIIString()，如您在OP：

import java.io.File;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.Slider;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.Priority;
import javafx.scene.layout.Region;
import javafx.scene.media.Media;
import javafx.scene.media.MediaPlayer;
import static javafx.scene.media.MediaPlayer.Status.HALTED;
import static javafx.scene.media.MediaPlayer.Status.PAUSED;
import static javafx.scene.media.MediaPlayer.Status.READY;
import static javafx.scene.media.MediaPlayer.Status.STOPPED;
import static javafx.scene.media.MediaPlayer.Status.UNKNOWN;
import javafx.scene.media.MediaView;
import javafx.stage.Stage;
import javafx.util.Duration;

public class SoundTest extends Application {

//  private static final String MEDIA_URL = "http://download.oracle.com/otndocs/products/javafx/oow2010-2.flv";
  private static final String MEDIA_URL = new File("test.mp3").toURI().toASCIIString();

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

  @Override
  public void start(Stage primaryStage) throws Exception {
    primaryStage.setTitle("Embedded Media Player");
    Group root = new Group();
    Scene scene = new Scene(root, 540, 241);

    // create media player
    Media media = new Media(MEDIA_URL);
    MediaPlayer mediaPlayer = new MediaPlayer(media);
    mediaPlayer.setAutoPlay(true);
    MediaControl mediaControl = new MediaControl(mediaPlayer);
    scene.setRoot(mediaControl);

    primaryStage.setScene(scene);
    primaryStage.show();

  }

  static class MediaControl extends BorderPane {
    private MediaPlayer mp;
    private MediaView mediaView;
    private final boolean repeat = false;
    private boolean stopRequested = false;
    private boolean atEndOfMedia = false;
    private Duration duration;
    private Slider timeSlider;
    private Label playTime;
    private Slider volumeSlider;
    private HBox mediaBar;

    public MediaControl(final MediaPlayer mp) {
      this.mp = mp;
      setStyle("-fx-background-color: #bfc2c7;");
      mediaView = new MediaView(mp);
      Pane mvPane = new Pane() {
      };

      mvPane.getChildren().add(mediaView);
      mvPane.setStyle("-fx-background-color: black;");
      setCenter(mvPane);

      mediaBar = new HBox();
      mediaBar.setAlignment(Pos.CENTER);
      mediaBar.setPadding(new Insets(5, 10, 5, 10));
      BorderPane.setAlignment(mediaBar, Pos.CENTER);

      final Button playButton = new Button(">");
      playButton.setOnAction(e -> {
        MediaPlayer.Status status = mp.getStatus();
        if (status == UNKNOWN || status == HALTED) {
          // don't do anything in these states
          return;
        }

        if (status == PAUSED
          || status == READY
          || status == STOPPED) {
          // rewind the movie if we're sitting at the end
          if (atEndOfMedia) {
            mp.seek(mp.getStartTime());
            atEndOfMedia = false;
          }
          mp.play();
        } else {
          mp.pause();
        }
      });
      mp.currentTimeProperty().addListener(ov -> {
        updateValues();
      });

      mp.setOnPlaying(() -> {
        if (stopRequested) {
          mp.pause();
          stopRequested = false;
        } else {
          playButton.setText("||");
        }
      });

      mp.setOnPaused(() -> {
        System.out.println("onPaused");
        playButton.setText(">");
      });

      mp.setOnReady(() -> {
        duration = mp.getMedia().getDuration();
        updateValues();
      });

      mp.setCycleCount(repeat ? MediaPlayer.INDEFINITE : 1);
      mp.setOnEndOfMedia(new Runnable() {
        public void run() {
          if (!repeat) {
            playButton.setText(">");
            stopRequested = true;
            atEndOfMedia = true;
          }
        }
      });
      mediaBar.getChildren().add(playButton);
      // Add spacer
      Label spacer = new Label("   ");
      mediaBar.getChildren().add(spacer);

      // Add Time label
      Label timeLabel = new Label("Time: ");
      mediaBar.getChildren().add(timeLabel);

      // Add time slider
      timeSlider = new Slider();
      HBox.setHgrow(timeSlider, Priority.ALWAYS);
      timeSlider.setMinWidth(50);
      timeSlider.setMaxWidth(Double.MAX_VALUE);
      timeSlider.valueProperty().addListener(ov -> {
        if (timeSlider.isValueChanging()) {
          // multiply duration by percentage calculated by slider position
          mp.seek(duration.multiply(timeSlider.getValue() / 100.0));
        }
      });
      mediaBar.getChildren().add(timeSlider);

      // Add Play label
      playTime = new Label();
      playTime.setPrefWidth(130);
      playTime.setMinWidth(50);
      mediaBar.getChildren().add(playTime);

      // Add the volume label
      Label volumeLabel = new Label("Vol: ");
      mediaBar.getChildren().add(volumeLabel);

      // Add Volume slider
      volumeSlider = new Slider();
      volumeSlider.setPrefWidth(70);
      volumeSlider.setMaxWidth(Region.USE_PREF_SIZE);
      volumeSlider.setMinWidth(30);
      volumeSlider.valueProperty().addListener(ov -> {
        if (volumeSlider.isValueChanging()) {
          mp.setVolume(volumeSlider.getValue() / 100.0);
        }
      });
      mediaBar.getChildren().add(volumeSlider);
      setBottom(mediaBar);
    }

    protected void updateValues() {
      if (playTime != null && timeSlider != null && volumeSlider != null) {
        Platform.runLater(() -> {
          Duration currentTime = mp.getCurrentTime();
          playTime.setText(formatTime(currentTime, duration));
          timeSlider.setDisable(duration.isUnknown());
          if (!timeSlider.isDisabled()
            && duration.greaterThan(Duration.ZERO)
            && !timeSlider.isValueChanging()) {
            timeSlider.setValue(currentTime.divide(duration).toMillis() * 100.0);
          }
          if (!volumeSlider.isValueChanging()) {
            volumeSlider.setValue((int) Math.round(mp.getVolume() * 100));
          }
        });
      }
    }

    private static String formatTime(Duration elapsed, Duration duration) {
      int intElapsed = (int) Math.floor(elapsed.toSeconds());
      int elapsedHours = intElapsed / (60 * 60);
      if (elapsedHours > 0) {
        intElapsed -= elapsedHours * 60 * 60;
      }
      int elapsedMinutes = intElapsed / 60;
      int elapsedSeconds = intElapsed - elapsedHours * 60 * 60 - elapsedMinutes * 60;

      if (duration.greaterThan(Duration.ZERO)) {
        int intDuration = (int) Math.floor(duration.toSeconds());
        int durationHours = intDuration / (60 * 60);
        if (durationHours > 0) {
          intDuration -= durationHours * 60 * 60;
        }
        int durationMinutes = intDuration / 60;
        int durationSeconds = intDuration - durationHours * 60 * 60 - durationMinutes * 60;
        if (durationHours > 0) {
          return String.format("%d:%02d:%02d/%d:%02d:%02d", elapsedHours, elapsedMinutes, elapsedSeconds, durationHours, durationMinutes, durationSeconds);
        } else {
          return String.format("%02d:%02d/%02d:%02d", elapsedMinutes, elapsedSeconds, durationMinutes, durationSeconds);
        }
      } else {
        if (elapsedHours > 0) {
          return String.format("%d:%02d:%02d", elapsedHours, elapsedMinutes, elapsedSeconds);
        } else {
          return String.format("%02d:%02d", elapsedMinutes, elapsedSeconds);
        }
      }
    }
  }
}

修改

使用原始问题中的代码，尝试用以下代码替换start方法：

@Override public void start(Stage arg0) throws Exception { sound(); // do { // } // while (true); }

然后，正如mipa已经回答：

阅读有关JavaFX并发的教程。

JavaFX媒体播放器不使用do while循环内部启动方法;

2 个答案: