当前页面: 开发资料首页 → J2ME 专题 → 熟练使用J2ME可选包MMAPI

熟练使用J2ME可选包MMAPI

摘要: 熟练使用J2ME可选包MMAPI

作者：mingjava 文章来源：J2ME开发网

了解J2ME可选包MMAPI一文向读者介绍了MMAPI的基本知识，掌握MMAPI的灵活性应该是重点。本文将讲述如何在实际开发中使用MMAPI。

本文的目的是为读者提供处理不同情况的代码，您可以参考MMAPI DOC。

播放单音
try {
Manager.playTone(ToneControl.C4, 5000 /* millisec */, 100 /* max vol */);
} catch (MediaException e) { }
简单媒体重放功能实现
try {
Player p = Manager.createPlayer("http://webserver/music.mp3");
p.setLoopCount(5);
p.start();
} catch (IOException ioe) {
} catch (MediaException me) { }
详细重放控制
static final long SECS_TO_MICROSECS = 1000000L;
Player p;
VolumeControl vc;
try {
p = Manager.createPlayer("http://webserver/music.mp3");
p.realize();
// Set a listener.
p.addPlayerListener(new Listener());
// Grab volume control for the player.
// Set Volume to max.
vc = (VolumeControl)p.getControl("VolumeControl");
if (vc != null)
vc.setLevel(100);
// Set a start time.
p.setMediaTime(5 * SECS_TO_MICROSECS);
// Guarantee that the player can start with the smallest latency.
p.prefetch();
// Non-blocking start
p.start();
} catch (IOException ioe) {
} catch (MediaException me) { }
class Listener implements PlayerListener {
public void playerUpdate(Player p, String event, Object eventData) {
if (event == END_OF_MEDIA || event == STOP_AT_TIME) {
System.out.println("Done processing");
try {
p.setMediaTime(5 * SECS_TO_MICROSECS);
p.start();
} catch (MediaException me) { }
break;
}
}
}

实现MIDI重放控制

Player p;

TempoControl tc;

try {

    p = Manager.createPlayer("http://webserver/tune.mid");

    p.realize();

    // Grab the tempo control.

    tc = (TempoControl)p.getControl("TempoControl");

    tc.setTempo(120000); // 120 beats/min

    p.start();

} catch (IOException ioe) {

} catch (MediaException me) { }

视频重放功能实现

Player p;

VideoControl vc;

try {

    p = Manager.createPlayer("http://webserver/movie.mpg");

    p.realize();

    // Grab the video control and set it to the current display.

    vc = (VideoControl)p.getControl("VideoControl");

    if (vc != null) {

        Form form = new Form("video");

        form.append((Item)vc.initDisplayMode(vc.USE_GUI_PRIMITIVE, null));

        Display.getDisplay(midlet).setCurrent(form);

    }

    p.start();

} catch (IOException ioe) {

} catch (MediaException me) { }

播放RMS内存储的数据

RecordStore rs;

int recordID;

   :  // code to set up the record store.

try {

    InputStream is = new

    ByteArrayInputStream(rs.getRecord(recordID));

    Player p = Manager.createPlayer(is, "audio/X-wav");

    p.start();

} catch (IOException ioe) {

} catch (MediaException me) { }

播放Jar文件中存储的媒体

/** Notice that in MIDP 2.0, the wav format is mandatory only */

/** in the case that the device supports sampled audio.       */

try {

    InputStream is = getClass().getResourceAsStream("audio.wav");

    Player p = Manager.createPlayer(is, "audio/X-wav");

    p.start();

} catch (IOException ioe) {

} catch (MediaException me) { }

不同Player的同步

Player p1, p2;

try {

    p1 = Manager.createPlayer("http://webserver/tune.mid");

    p1.realize();

    p2 = Manager.createPlayer("http://webserver/movie.mpg");

    p2.realize();

    p2.setTimeBase(p1.getTimeBase());

    p1.prefetch();

    p2.prefetch();

    p1.start();

    p2.start();

} catch (IOException ioe) {

} catch (MediaException me) { }

产生单音序列
byte tempo = 30; // set tempo to 120 bpm
byte d = 8; // eighth-note

byte C4 = ToneControl.C4;;
byte D4 = (byte)(C4 + 2); // a whole step
byte E4 = (byte)(C4 + 4); // a major third
byte G4 = (byte)(C4 + 7); // a fifth
byte rest = ToneControl.SILENCE; // rest

byte[] mySequence = {
ToneControl.VERSION, 1, // version 1
ToneControl.TEMPO, tempo, // set tempo
ToneControl.BLOCK_START, 0, // start define "A" section
E4,d, D4,d, C4,d, E4,d, // content of "A" section
E4,d, E4,d, E4,d, rest,d,
ToneControl.BLOCK_END, 0, // end define "A" section
ToneControl.PLAY_BLOCK, 0, // play "A" section
D4,d, D4,d, D4,d, rest,d, // play "B" section
E4,d, G4,d, G4,d, rest,d,
ToneControl.PLAY_BLOCK, 0, // repeat "A" section
D4,d, D4,d, E4,d, D4,d, C4,d // play "C" section
};

try{
Player p = Manager.createPlayer(Manager.TONE_DEVICE_LOCATOR);
p.realize();
ToneControl c = (ToneControl)p.getControl("ToneControl");
c.setSequence(mySequence);
p.start();
} catch (IOException ioe) {
} catch (MediaException me) { }

语音捕获和录音功能的实现

try {

    // Create a DataSource that captures live audio.

    Player p = Manager.createPlayer("capture://audio");

    p.realize();

    // Get the RecordControl, set the record location, and

    // start the Player and record for 5 seconds.

    RecordControl rc = (RecordControl)p.getControl("RecordControl");

    rc.setRecordLocation("file:/tmp/audio.wav");

    rc.startRecord();

    p.start();

    Thread.currentThread().sleep(5000);

    p.stop();

    rc.stopRecord();

    rc.commit();

} catch (IOException ioe) {

} catch (MediaException me) {

} catch (InterruptedException e) { }

实现摄像功能
Player p;

VideoControl vc;

// initialize camera

try {

    p = Manager.createPlayer("capture://video");

    p.realize();

    // Grab the video control and set it to the current display.

    vc = (VideoControl)p.getControl("VideoControl");

    if (vc != null) {

        Form form = new Form("video");

        form.append((Item)vc.initDisplayMode(vc.USE_GUI_PRIMITIVE, null));

        Display.getDisplay(midlet).setCurrent(form);

    }

    p.start();

} catch (IOException ioe) {

} catch (MediaException me) { }

// now take a picture

try {

    byte[] pngImage = vc.getSnapshot(null);

    // do something with the image ...

} catch (MediaException me) { }


在后面的文章中我们将通过完整的实例演示如何使用MMAPI开发应用程序。

</td></tr></table>

↑返回目录
前一篇: J2ME WEB服务入门教程
后一篇: 了解J2ME可选包MMAPI