videoplayer_midlet.java

本光盘是《J2ME无线移动游戏开发》一书的配套光盘

package ch11;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class VideoPlayer_MIDlet
    extends MIDlet
    implements CommandListener {

  //声明一个Display对象
  private Display display;

  //声明一个Form对象
  public Form form;

  //声明一个获取视频文件地址TextField对象
  private TextField textField;

  //声明一个退出按钮Command对象
  private Command exitCommand;

  //声明一个播放按钮Command对象
  private Command playCommand;

  //声明一个类型支持按钮Command对象
  private Command contentTypeCommand;

  //声明一个代表装载视频文件进度的Gauge对象
  private Gauge gauge;

  //控制Gauge对象的变化速度
  private static final int GAUGE_LEVELS = 4;

  //声明Gauge对象的最大值
  private static final int GAUGE_MAX = 12;

  //声明视频文件的默认地址
  private static final String DEFAULT_URL = "http://localhost/test.mpg";

  /*
   1.构造器
   */
  public VideoPlayer_MIDlet() {
    display = Display.getDisplay(this);
    form = new Form("视频播放器");
    textField = new TextField("视频地址", DEFAULT_URL, 100, TextField.ANY);
    gauge = new Gauge("装载视频", false, GAUGE_MAX, 0);
    exitCommand = new Command("退出", Command.EXIT, 2);
    playCommand = new Command("播放", Command.SCREEN, 1);
    contentTypeCommand = new Command("支持媒体类型", Command.SCREEN, 2);
    form.addCommand(playCommand);
    form.addCommand(exitCommand);
    form.addCommand(contentTypeCommand);
    form.setCommandListener(this);
    form.append(textField);
    display.setCurrent(form);
  }

  //启动应用程序
  public void startApp() {
  }

  //挂起应用程序
  public void pauseApp() {
  }

  //撤销应用程序
  public void destroyApp(boolean unconditional) {
  }

  /*
   2.响应按钮事件
   */
  public void commandAction(Command c, Displayable s) {

    if (c == exitCommand) {
      destroyApp(false);
      notifyDestroyed();
    }

    else if (c == playCommand) {
      gauge.setValue(0);
      form.append(gauge);

      VideoCanvas videoCanvas = new VideoCanvas(this);
      videoCanvas.initializeVideo(textField.getString());
    }

    else if (c == contentTypeCommand) {
      String url = textField.getString();
      int position = url.indexOf(':');
      String protocol = url.substring(0, position);

      SupportedTypes typesUI = new SupportedTypes(this, protocol);
      display.setCurrent(typesUI);
    }

  }

  /*
   3.更新进度条
   */
  public void updateGauge() {
    int current = gauge.getValue();
    current = (current + GAUGE_MAX / GAUGE_LEVELS);
    gauge.setValue(current);
  }

}