Question

这是我关于JavaFX的第二个问题。我很抱歉因为我不是一个经验丰富的Java程序员，而且是JavaFX的新手。我不完全理解以前的答案，并会在以后一次又一次地阅读。但现在我有下一个问题。我按如下方式重写了我的程序：

 import java.io.FileNotFoundException;
 import java.io.IOException;
 import static java.lang.Thread.sleep;
 import java.util.concurrent.TimeUnit;
 import javafx.application.Application;
 import javafx.scene.media.Media;
 import javafx.scene.media.MediaPlayer;
 import javafx.stage.Stage; import javafx.util.Duration;

 public class JavaFXMediaPlayer05 extends Application {

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

     @Override
     public void start(Stage stage) throws FileNotFoundException,IOException, InterruptedException {
         Media media = new Media("file:///D:/1016_00.mp3");
 //Set and play the first fragment of mp3-file
         MediaPlayer mediaPlayer1 = new MediaPlayer(media);
         mediaPlayer1.setStartTime(Duration.millis(1219.0));
         mediaPlayer1.setStopTime(Duration.millis(2728.0));
         mediaPlayer1.play();
         System.out.println("1st fragment played!");
         TimeUnit.SECONDS.sleep(3);
 //Set and play the second fragment
         MediaPlayer mediaPlayer2 = new MediaPlayer(media);
         mediaPlayer2.setStartTime(Duration.millis(3947.0));
         mediaPlayer2.setStopTime(Duration.millis(6629.0));
         mediaPlayer2.play();
         System.out.println("2nd fragment played!");
         TimeUnit.SECONDS.sleep(3);
 //Set and play the third fragment
         MediaPlayer mediaPlayer3 = new MediaPlayer(media);
         mediaPlayer3.setStartTime(Duration.millis(7453.0));
         mediaPlayer3.setStopTime(Duration.millis(10704.0));
         mediaPlayer3.play();
         System.out.println("3rd fragment played!");
 //Just sleep
         System.out.println("pre-sleep");
         TimeUnit.SECONDS.sleep(3);
         System.out.println("after-sleep");
     }
 }

我在NetBeans中逐步调试它。我得到一个奇怪的结果。我听到的声音不是在mediaplayer.play（），而是在方法start（）的末尾。所有3个片段一次播放。如何管理它们按顺序播放？我是否需要多次触发方法start（） - 每个片段一次？或者还有另一种方式吗？

Answer 1

MediaPlayer开始异步播放媒体。所以mediaPlayerN.play()同时发生。

您可以使用Timeline在特定时间开始播放，请参阅下文。

此外，由于所有播放器只有1个媒体，因此您可以对所有样本使用相同的MediaPlayer。请注意，在这种情况下，您应该使用seek()方法而不是setStartTime()。

final MediaPlayer mediaPlayer1 = new MediaPlayer(media);
Timeline timeline = new Timeline(
    new KeyFrame(Duration.ZERO, "plays at start", new EventHandler<ActionEvent>() {

        @Override
        public void handle(ActionEvent t) {
            mediaPlayer1.setStartTime(Duration.millis(1219.0));
            mediaPlayer1.setStopTime(Duration.millis(2728.0));
            mediaPlayer1.play();
        }
    }),
    new KeyFrame(Duration.seconds(5), "plays after 5 seconds", new EventHandler<ActionEvent>() {

        @Override
        public void handle(ActionEvent t) {
            mediaPlayer1.seek(Duration.millis(3947.0));
            mediaPlayer1.setStopTime(Duration.millis(6629.0));
            mediaPlayer1.play();
        }
    }),
    new KeyFrame(Duration.seconds(10), "plays after 10 seconds", new EventHandler<ActionEvent>() {

        @Override
        public void handle(ActionEvent t) {
            mediaPlayer1.seek(Duration.millis(7453.0));
            mediaPlayer1.setStopTime(Duration.millis(10704.0));
            mediaPlayer1.play();
        }
    })
);
timeline.play();

如何同步播放mp3的几个片段？

1 个答案: