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cocos2dx 音频模块分析(5): 音效部分
我们上一篇中分析的音效部分的预加载和播放函数，这一篇来分析下其他函数：
1、
暂停某个播放中的音效
//注意这里的nSoundId不是java端的soundID，而是streamID
//不要被参数的名字迷惑了。
void SimpleAudioEngine::pauseEffect(unsigned int nSoundId)
{
pauseEffectJNI(nSoundId);
}
-->>
void pauseEffectJNI(unsigned int nSoundId)
{
// void pauseEffect(int)
JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "pauseEffect", "(I)V"))
{
return ;
}
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID, (int)nSoundId);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
---->>//java端方法：
//pStreamID 这个参数，是调用unsigned int SimpleAudioEngine::playEffect()放回的StreamID
public void pauseEffect(final int pStreamID) {
/**
* Pause a playback stream. 暂停一个播放流
*
* Pause the stream specified by the streamID. This is the
* value returned by the play() function. (这个值是play函数的返回值)If the stream is
* playing, it will be paused. If the stream is not playing
* (e.g. is stopped or was previously paused), calling this
* function will have no effect.(如果处于播放状态则暂停，如果不处于播放状态，则无效)
*
* @param streamID a streamID returned by the play() function
*/
this.mSoundPool.pause(pStreamID);
}
2、
暂停所有音效
void pauseAllEffectsJNI()
{
// void pauseAllEffects()
JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "pauseAllEffects", "()V"))
{
return ;
}
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
--->>java端
public void pauseAllEffects() {
/**
* Pause all active streams. //暂停所有正在播放的音效
*
* Pause all streams that are currently playing. This function
* iterates through all the active streams and pauses any that
* are playing. It also sets a flag so that any streams that
* are playing can be resumed by calling autoResume().
*/
this.mSoundPool.autoPause();
}
3、
恢复播放某个音效
void resumeEffectJNI(unsigned int nSoundId)
{
// void resumeEffect(int)
JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "resumeEffect", "(I)V"))
{
return ;
}
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID, (int)nSoundId);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
--->>
public void resumeEffect(final int pStreamID) {
/**
* Resume a playback stream.
* 只有处于暂停状态的stream，才可以恢复播放。
* Resume the stream specified by the streamID. This
* is the value returned by the play() function. If the stream
* is paused, this will resume playback. If the stream was not
* previously paused, calling this function will have no effect.
*
* @param streamID a streamID returned by the play() function
*/
this.mSoundPool.resume(pStreamID);
}
4、
void resumeAllEffectsJNI()
{
// void resumeAllEffects()
JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "resumeAllEffects", "()V"))
{
return ;
}
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
---->>>java端函数：
public void resumeAllEffects() {
// can not only invoke SoundPool.autoResume() here, because
// it only resumes all effects paused by pauseAllEffects()
// 这里注释的很清楚
if (!this.mPathStreamIDsMap.isEmpty()) {
final Iterator<Entry<String, ArrayList<Integer>>> iter = this.mPathStreamIDsMap.entrySet().iterator();
while (iter.hasNext()) {
final Entry<String, ArrayList<Integer>> entry = iter.next();
for (final int pStreamID : entry.getValue()) {
this.mSoundPool.resume(pStreamID);
}
}
}
}
5、
停止播放某个音效，这里的nSoundId同样是pStreamID，停止播放的音效是不能
通过resume恢复播放的。
void SimpleAudioEngine::stopEffect(unsigned int nSoundId)
{
stopEffectJNI(nSoundId);
}
--->>java端：
public void stopEffect(final int pStreamID) {
/**
* Stop a playback stream.
*
* Stop the stream specified by the streamID. This
* is the value returned by the play() function. If the stream
* is playing, it will be stopped. It also releases any native
* resources associated with this stream. (会释放对应的资源)If the stream is not
* playing, it will have no effect.
*
* @param streamID a streamID returned by the play() function
*/
this.mSoundPool.stop(pStreamID);
// remove record
// 从记录列表中移除
for (final String pPath : this.mPathStreamIDsMap.keySet()) {
if (this.mPathStreamIDsMap.get(pPath).contains(pStreamID)) {
this.mPathStreamIDsMap.get(pPath).remove(this.mPathStreamIDsMap.get(pPath).indexOf(pStreamID));
break;
}
}
}
6、
void stopAllEffectsJNI()
{
// void stopAllEffects()
JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "stopAllEffects", "()V"))
{
return ;
}
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
--->>>java端
@SuppressWarnings("unchecked")
public void stopAllEffects() {
// stop effects，停止所有音效的播放
if (!this.mPathStreamIDsMap.isEmpty()) {
final Iterator<?> iter = this.mPathStreamIDsMap.entrySet().iterator();
while (iter.hasNext()) {
final Map.Entry<String, ArrayList<Integer>> entry = (Map.Entry<String, ArrayList<Integer>>) iter.next();
for (final int pStreamID : entry.getValue()) {
this.mSoundPool.stop(pStreamID);
}
}
}
// remove records，清空播放记录
this.mPathStreamIDsMap.clear();
}
7、
卸载加载的音效(重要)
//pszFilePath：音效文件名
void SimpleAudioEngine::unloadEffect(const char* pszFilePath)
{
std::string fullPath = getFullPathWithoutAssetsPrefix(pszFilePath);
unloadEffectJNI(fullPath.c_str());
}
--->>
void unloadEffectJNI(const char* path)
{
// void unloadEffect(String)
JniMethodInfo methodInfo;
if (! getStaticMethodInfo(methodInfo, "unloadEffect", "(Ljava/lang/String;)V"))
{
return ;
}
jstring stringArg = methodInfo.env->NewStringUTF(path);
methodInfo.env->CallStaticVoidMethod(methodInfo.classID, methodInfo.methodID, stringArg);
methodInfo.env->DeleteLocalRef(stringArg);
methodInfo.env->DeleteLocalRef(methodInfo.classID);
}
--->>>
public void unloadEffect(final String pPath) {
// stop effects
// 先停止
final ArrayList<Integer> streamIDs = this.mPathStreamIDsMap.get(pPath);
if (streamIDs != null) {
for (final Integer pStreamID : streamIDs) {
this.mSoundPool.stop(pStreamID);
}
}
this.mPathStreamIDsMap.remove(pPath);
// unload effect
final Integer soundID = this.mPathSoundIDMap.get(pPath);
if(soundID != null){
/**
* Unload a sound from a sound ID.
*
* Unloads the sound specified by the soundID. This is the value
* returned by the load() function. Returns true if the sound is
* successfully unloaded, false if the sound was already unloaded.
*
* @param soundID a soundID returned by the load() function
* @return true if just unloaded, false if previously unloaded
*/
// 卸载音效
this.mSoundPool.unload(soundID);
// 从mPathSoundIDMap中移除
this.mPathSoundIDMap.remove(pPath);
}
}
/************************************************
总结:
音效部分最重要的函数是preloadEffect，unloadEffect，playEffect，stopAllEffects
其他的感觉不是很常用，java有两个比较重要的map，一个是：
private final HashMap<String, Integer> mPathSoundIDMap = new HashMap<String, Integer>();
这个是用来存放所有加载的音效文件路径和SoundID的map。
一个是：
// sound path and stream ids map cocos2dx原本注释
// a file may be played many times at the same time
// so there is an array map to a file path
private final HashMap<String, ArrayList<Integer>> mPathStreamIDsMap = new HashMap<String, ArrayList<Integer>>();
用来存放所有播放的音效文件路径和StreamIDs的map。
注意：这里的SoundID和StreamID不是一个概念，一个音效文件只对应一个SoundID，而却可以对应多个StreamID，因为一个
音效文件可以播放多次(StreamID)，但是只需要加载一次(SoundID).
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原文地址：http://blog.csdn.net/tianxiawuzhei/article/details/45933769
