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📜  vlcj-加载视频事件时出错

📅  最后修改于: 2020-10-14 08:54:55             🧑  作者: Mango

让我们进一步增强应用程序，在其中我们将更新具有错误处理功能的vlcj-成品视频事件一章。

处理错误事件

使用以下语法（模板方法）添加错误事件处理程序：

mediaPlayerComponent = new EmbeddedMediaPlayerComponent() {
   @Override
   public void error(MediaPlayer mediaPlayer) {
   }
};

或者我们可以使用以下语法（侦听器方法）添加错误事件处理程序：

mediaPlayerComponent.getMediaPlayer().addMediaPlayerEventListener(new MediaPlayerEventAdapter() {
   @Override
   public void error(MediaPlayer mediaPlayer) {
   }
});

如果视频加载失败，则会引发错误事件。但是随着play方法立即返回，并且稍后会引发错误事件（如果视频已加载且无法运行）。因此，我们必须以异步方式处理错误事件。

例

打开在Eclipse的“环境设置”一章中创建的项目mediaPlayer。

使用以下代码更新App.java-

App.java

package com.tutorialspoint.media;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import uk.co.caprica.vlcj.player.base.MediaPlayer;
import uk.co.caprica.vlcj.player.component.EmbeddedMediaPlayerComponent;

public class App extends JFrame {
   private static final long serialVersionUID = 1L;
   private static final String TITLE = "My First Media Player";
   private static final String VIDEO_PATH = "D:\\Downloads\\sunset-beach.mp4";
   private final EmbeddedMediaPlayerComponent mediaPlayerComponent;
   private JButton playButton;
   private JButton pauseButton;
   private JButton rewindButton;
   private JButton skipButton;

   public App(String title) {
      super(title);
      mediaPlayerComponent = new EmbeddedMediaPlayerComponent() {
         @Override
         public void playing(MediaPlayer mediaPlayer) {
            super.playing(mediaPlayer);
            System.out.println("Media Playback started.");
         }
         @Override
         public void finished(MediaPlayer mediaPlayer) {
            super.playing(mediaPlayer);
            System.out.println("Media Playback finished.");
         }
         @Override
         public void error(MediaPlayer mediaPlayer) {
            SwingUtilities.invokeLater(new Runnable() {                
               public void run() {
                  System.out.println("Failed to load Media.");
               }                   
            });
         }
      };        
   }
   public void initialize() {
      this.setBounds(100, 100, 600, 400);
      this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      this.addWindowListener(new WindowAdapter() {
         @Override
         public void windowClosing(WindowEvent e) {
            mediaPlayerComponent.release();
            System.exit(0);
         }
      });        
      JPanel contentPane = new JPanel();
      contentPane.setLayout(new BorderLayout());        
      contentPane.add(mediaPlayerComponent, BorderLayout.CENTER);
      JPanel controlsPane = new JPanel();
      playButton = new JButton("Play");
      controlsPane.add(playButton);    
      pauseButton = new JButton("Pause");
      controlsPane.add(pauseButton);
      rewindButton = new JButton("Rewind");
      controlsPane.add(rewindButton);
      skipButton = new JButton("Skip");
      controlsPane.add(skipButton);
      contentPane.add(controlsPane, BorderLayout.SOUTH);

      playButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            mediaPlayerComponent.mediaPlayer().controls().play();
         }
      });  
      pauseButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            mediaPlayerComponent.mediaPlayer().controls().pause();
         }
      });
      rewindButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            mediaPlayerComponent.mediaPlayer().controls().skipTime(-14000);
         }
      });
      skipButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            mediaPlayerComponent.mediaPlayer().controls().skipTime(4000);
         }
      });
      this.setContentPane(contentPane);
      this.setVisible(true);
   }
   public void loadVideo(String path) {
      mediaPlayerComponent.mediaPlayer().media().startPaused(path);       
   }
   public static void main( String[] args ){
      try {            
         UIManager.setLookAndFeel(
         UIManager.getSystemLookAndFeelClassName());
      } 
      catch (Exception e) {
         System.out.println(e);
      }
      App application = new App(TITLE);
      application.initialize(); 
      application.setVisible(true);  
      application.loadVideo(VIDEO_PATH);
   }
}

此处提供了指向媒体文件的无效路径。通过右键单击文件来运行应用程序，然后选择以Java应用程序运行。成功启动后，如果一切正常，则应显示以下结果-

跳过视频

现在将在控制台中看到如下消息：

Failed to load Media.