第五次作业

import javax.media.;
import java.awt.;
import java.awt.event.;
class MediaPlayer extends Frame implements ActionListener,
ControllerListener, ItemListener
{
Player player;
Component vc, cc;
boolean first = true, loop = false;
String currentDirectory;
MediaPlayer (String title)
{
super (title);
addWindowListener
(new WindowAdapter ()
{
public void windowClosing (WindowEvent e) {
// 用户点击窗口系统菜单的关闭按钮
// 调用dispose以执行windowClosed
dispose ();
} public void windowClosed (WindowEvent e) {
if (player != null) player.close ();
System.exit (0);
}
});
Menu m = new Menu ("文件");
MenuItem mi = new MenuItem ("打开");
mi.addActionListener (this);
m.add (mi);
m.addSeparator ();
CheckboxMenuItem cbmi = new CheckboxMenuItem ("循环", false);
cbmi.addItemListener (this);
m.add (cbmi);
m.addSeparator ();
mi = new MenuItem ("退出");
mi.addActionListener (this);
m.add (mi);
MenuBar mb = new MenuBar ();
mb.add (m);
setMenuBar (mb);
setSize (200, 200);
setVisible (true);
}
public void actionPerformed (ActionEvent e)
{
if (e.getActionCommand ().equals ("退出"))
{
// 调用dispose以便执行windowClosed
dispose ();
return;
}
FileDialog fd = new FileDialog (this, "打开媒体文件",
FileDialog.LOAD);
fd.setDirectory (currentDirectory);
fd.show ();
// 如果用户放弃选择文件，则返回
if (fd.getFile () == null) return;
currentDirectory = fd.getDirectory ();
if (player != null)
player.close ();
try
{
player = Manager.createPlayer (new MediaLocator ("file:" + fd.getDirectory () + fd.getFile ()));
}
catch (java.io.IOException e2)
{
System.out.println (e2);
return;
}
catch (NoPlayerException e2)
{
System.out.println ("不能找到播放器.");
return;
}
if (player == null)
{
System.out.println ("无法创建播放器.");
return;
}
first = false;
setTitle (fd.getFile ());
player.addControllerListener (this);
player.prefetch ();
}
public void controllerUpdate (ControllerEvent e)
{
// 调用player.close()时ControllerClosedEvent事件出现。
// 如果存在视觉部件，则该部件应该拆除（为一致起见，
// 我们对控制面板部件也执行同样的操作）
if (e instanceof ControllerClosedEvent)
{
if (vc != null)
{
remove (vc);
vc = null;
}
if (cc != null)
{
remove (cc);
cc = null;
}
return;
}
if (e instanceof EndOfMediaEvent)
{
if (loop)
{
player.setMediaTime (new Time (0));
player.start ();
}
return;
}
if (e instanceof PrefetchCompleteEvent)
{
player.start ();
return;
}
if (e instanceof RealizeCompleteEvent)
{
vc = player.getVisualComponent ();
if (vc != null)
add (vc);
cc = player.getControlPanelComponent ();
if (cc != null)
add (cc, BorderLayout.SOUTH);
pack ();
}
}
public void itemStateChanged (ItemEvent e)
{
loop = !loop;
}
public void paint (Graphics g)
{
if (first)
{
int w = getSize ().width;
int h = getSize ().height;
g.setColor (Color.blue);
g.fillRect (0, 0, w, h);
Font f = new Font ("DialogInput", Font.BOLD, 16);
g.setFont (f);
FontMetrics fm = g.getFontMetrics ();
int swidth = fm.stringWidth ("** 欢迎 ");
g.setColor (Color.white);
g.drawString (" 欢迎 ***",
(w - swidth) / 2,
(h + getInsets ().top) / 2);
}
// 调用超类Frame的paint()方法，该paint()方法将调用Frame包含的各个容器
// 和部件（包括控制面板部件）的paint()方法。
super.paint (g);
}
// 不执行背景清除操作，以免控制面板部件闪烁
public void update (Graphics g)
{
paint (g);
}
public static void main (String [] args) {
new MediaPlayer ("媒体播放器1.0");
} }