simpleplayergui.java

一个非常典型的J2ME多媒体应用例子

	fullScreen = false;
	toggleFullScreen();
    }

    private void normalScreenPressed() {
	fullScreen = true;
	toggleFullScreen();
    }

    public void stepFrame(int frames) {
	FramePositioningControl fpc = getFramePositioningControl();
	if (fpc != null) {
	    fpc.skip(frames);
	} else {
	    setFeedback("No FramePositioningControl!");
	}
    }

    // /////////////////////////// CONTROLS ///////////////////////////////////

    public boolean hasRateControl() {
	return getRateControl()!=null;
    }

    public boolean hasTempoControl() {
	return getTempoControl()!=null;
    }

    public boolean hasGUIControls() {
	// a player which provides VideoControl should also
	// always return GUIControl. Just to be sure...
	try {
	    if (player != null) {
		return ((player.getControl("GUIControl")!=null)
			|| (player.getControl("VideoControl")!=null));
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return false;
    }

    public Control[] getControls() {
	try {
	    if (player != null) {
		return player.getControls();
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private VolumeControl getVolumeControl() {
	try {
	    if (player != null) {
		return (VolumeControl) player.getControl("VolumeControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private TempoControl getTempoControl() {
	try {
	    if (player != null) {
		return (TempoControl) player.getControl("TempoControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private RateControl getRateControl() {
	try {
	    if (player != null) {
		return (RateControl) player.getControl("RateControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private PitchControl getPitchControl() {
	try {
	    if (player != null) {
		return (PitchControl) player.getControl("PitchControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private MetaDataControl getMetaDataControl() {
	try {
	    if (player != null) {
		return (MetaDataControl) player.getControl("MetaDataControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private FramePositioningControl getFramePositioningControl() {
	try {
	    if (player != null) {
		return (FramePositioningControl) player.getControl("FramePositioningControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    private StopTimeControl getStopTimeControl() {
	try {
	    if (player != null) {
		return (StopTimeControl) player.getControl("StopTimeControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    public VideoControl getVideoControl() {
	try {
	    if (player != null) {
		return (VideoControl) player.getControl("VideoControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    public RecordControl getRecordControl() {
	try {
	    if (player != null) {
		return (RecordControl) player.getControl("RecordControl");
	    }
	} catch (IllegalStateException ise) {
	    // thrown when player is closed
	}
	return null;
    }

    // /////////////////////////// PLAYBACK CONTROL ///////////////////////////

    private void assertPlayer() throws Throwable {
	String state="";
	try {
	    debugOut("assertPlayer");
	    fullScreen = false;
	    // make sure we can go back, even if failed
	    display.removeCommand(backCommand);
	    display.addCommand(backCommand);
	    if (player == null) {
		if (songInputStream == null) {
		    state="Opening "+songLocator; setStatus(state+"...");
		    player = Manager.createPlayer(songLocator);
		} else {
		    state="Opening "+songName; setStatus(state+"...");
		    player = Manager.createPlayer(songInputStream, songContentType);
		}
	    }
	    player.addPlayerListener(this);
	    //System.out.println("player = " + player);
	    state="Realizing"; setStatus(state+"...");
	    player.realize();
	    state="Prefetching"; setStatus(state+"...");
	    player.prefetch();
	    state="Prefetched"; setStatus(state);
	    if (USE_FORM_PLAYER_FOR_VIDEO) {
		// MAGIC: if there are any GUI controls, switch to Form mode
		// this is not nice design...
		if (hasGUIControls() && !(parent instanceof SimplePlayerForm)) {
		    System.gc();
		    state="Setting up GUI"; setStatus(state+"...");
		    Parent newParent = new SimplePlayerForm(parent.getTitle(), this, parent.getParent());
		    debugOut("created");
		    setParent(newParent);
		    parent.replaceCurrent(display);
		    state="GUI is set up."; setStatus(state);
		    debugOut("Changed to form-based player.");
		}
	    }
	    setPlayerCommands();
	    // notify the display class
	    parent.setupDisplay();

	    // use TITLE meta data if existant for display
	    MetaDataControl mc = getMetaDataControl();
	    if (mc != null) {
		int titleCount=0;
		String title = "";
		try {
		    title = mc.getKeyValue(MetaDataControl.TITLE_KEY);
		    if (title != null && title != "") {
			titleCount++;
			while (true) {
			    String n = mc.getKeyValue(MetaDataControl.TITLE_KEY+(titleCount+1));
			    if (n == null || n == "") {
				break;
			    }
			    titleCount++;
			}
		    }
		} catch (IllegalArgumentException me) {
		    // title key doesn't exist
		}
		// now number of titles is known
		if (titleCount > 0) {
		    songDisplayNames = new String[titleCount];
		    songDisplayNames[0] = title;
		    try {
			for (int i=1; i<titleCount; i++) {
			    songDisplayNames[i] = mc.getKeyValue(MetaDataControl.TITLE_KEY+(i+1));
			}
		    } catch (IllegalArgumentException me) {}
		    currSongDisplay = 0;
		}
		try {
		    String l = mc.getKeyValue(LYRICS_KEY);
		    if (l != null && l != "") {
			karaokeMode = true;
			karaokeLyrics = l;
		    }
		} catch (IllegalArgumentException me) {
		    // lyrics key doesn't exist
		}
	    }
	    durationUpdated();
	} catch (Throwable t) {
	    player=null;
	    setStatus("");
	    throw new MediaException(Utils.friendlyException(t)+" at "+state);
	}
    }


    public void startPlayer() {
	try {
	    debugOut("startPlayer");
	    if (player == null || player.getState() < Player.PREFETCHED) {
		assertPlayer();
	    }
	    if (player == null || player.getState() >= Player.STARTED) {
		return;
	    }
	    updateLoop();
	    // auto-rewind
	    try {
		long duration = player.getDuration();
		if (duration != Player.TIME_UNKNOWN && player.getMediaTime() >= duration) {
		    player.setMediaTime(0);
		}
	    } catch (MediaException e) {
		// nothing to do
	    }
	    if (player.getMediaTime() == 0) {
		setupKaraokeLines(0, 0);
		updateKaraoke();
	    } else {
		clearKaraoke();
	    }
	    setStatus("Starting...");
	    player.start();
	    setStatus("Playing");
	    setFeedback("");
	    // tempo may have changed due to new position
	    updateTempo(null);
	} catch (Throwable t) {
	    error(t);
	}
    }

    public void closePlayer() {
	if (player != null) {
	    setStatus("Stopping...");
	    try {
		player.stop();
	    } catch (Exception e) {}
	    setStatus("Closing...");
	    player.close();
	    setStatus("Closed");
	    player = null;
	    initialize();
	}
    }


    public void pausePlayer() {
	if (player != null) {
	    setStatus("Stopping...");
	    try {
		player.stop();
	    } catch (Exception e) {}
	    setStatus("Stopped");
	    setFeedback("");
	}
    }

    public void togglePlayer() {
	if (player!=null) {
	    if (player.getState() == Player.STARTED) {
		pausePlayer();
	    } else {
		startPlayer();
	    }
	}
    }

    /** fast forward or fast backward */
    public void skip(boolean backwards) {
	if (player != null) {
	    try {
		long mTime = player.getMediaTime();
		// default 10 sec
		long jump = 10000000;
		long duration = player.getDuration();
		if (duration >= 0) {
		    // skip 5%
		    jump = duration / 20;
		    if (jump < 2000000)
			jump = 2000000; // Skip at least 2 seconds
		}
		if (backwards) {
		    // Jump backward
		    setMediaTime(mTime-jump);
		} else {
		    // Jump forward
		    setMediaTime(mTime+jump);
		}
	    } catch (IllegalStateException ise) {
		// thrown when player is closed
		error(ise);
	    }
	}
    }

    public void stopAfterTime() {
	int delay = 5000000; // 5 seconds
	StopTimeControl stc = getStopTimeControl();
	if (stc != null) {
	    try {
		stc.setStopTime(StopTimeControl.RESET);
		stc.setStopTime(player.getMediaTime()+delay);
		setFeedback("Stop in "+(delay/1000000)+" seconds.");
	    } catch (IllegalStateException ise) {
		error(ise);
	    }
	} else {
	    setFeedback("No StopTimeControl!");
	}
    }

    public void changeRate(boolean slowdown) {
	int diff = 10000; // 10%
	if (slowdown) {
	    diff = -diff;
	}
	RateControl rc = getRateControl();
	if (rc != null) {
	    int ocr = rc.getRate();
	    int ncr = ocr + diff;
	    int maxRate = rc.getMaxRate();
	    if (maxRate > LIMIT_RATE*1000) {
		maxRate = LIMIT_RATE * 1000;
	    }
	    if (ncr >= rc.getMinRate() && ncr <= maxRate) {
		int ecr = rc.setRate(ncr);
		setFeedback("New rate: "+toFloatString(ecr, 3)+"%");
		updateRate(rc);
		// rate changes effective tempo.
		updateTempo(null);
	    }
	} else {
	    setFeedback("No RateControl!");
	}
    }

    public void setMediaTime(long time) {
	if (player == null) {
	    return;
	}
	try {
	    setFeedback("Set MediaTime to "+timeDisplay(time));
	    player.setMediaTime(time);
	    updateTime();
	    clearKaraoke();
	    updateTempo(null);
	} catch (Exception e) {
	    error(e);
	}
    }

    public void changeVolume(boolean decrease) {
	int diff = 10;
	if (decrease) {
	    diff = -diff;
	}
	VolumeControl vc = getVolumeControl();
	if (vc != null) {
	    int cv = vc.getLevel();
	    cv += diff;
	    vc.setLevel(cv);
	    updateVolume(vc);
	} else {
	    setFeedback("No VolumeControl!");
	}
    }

    public void toggleMute() {
	VolumeControl vc = getVolumeControl();
	if (vc != null) {
	    vc.setMute(!vc.isMuted());
	    updateVolume(vc);
	} else {
	    setFeedback("No VolumeControl!");
	}
    }

    public void transpose(boolean down) {
	int diff = 1000; // 1 semitone
	if (down) {
	    diff = -diff;
	}
	PitchControl pc = getPitchControl();
	if (pc != null) {