JNI在Android开发中的应用之-用AudioRecord录音，用AudioTrack播放声音

下面是主Activity.package com.example.hellojni;import android.app.Activity;import android.os.Bundle;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import java.io.BufferedOutputStream;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class HelloJni extends Activity{	Button startRecord;	Button stopRecord;	Button play;	static BufferedOutputStream bos;    static {        System.loadLibrary("hello-jni");    }    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        startRecord = (Button)findViewById(R.id.start);        stopRecord = (Button)findViewById(R.id.stop);        play  =(Button)findViewById(R.id.play);        startRecord.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				new Thread(){					public void run(){						initOutputStream();						startRecord();					}				}.start();			}		});        stopRecord.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				new Thread(){					public void run(){						stopRecord();						try{							Thread.sleep(1000*2);							if(bos!=null){								try {									bos.close();								} catch (IOException e) {									// TODO Auto-generated catch block									e.printStackTrace();								}							}						}catch(Exception e){						}					}				}.start();			}		});        play.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				new Thread(){public void run(){play();}}.start();			}		});    }    public void initOutputStream(){    		File file = new File("/sdcard/temp.pcm");    		try {				bos = new BufferedOutputStream(new FileOutputStream(file));			} catch (FileNotFoundException e) {				e.printStackTrace();			}    }    public static void receiveAudioData(byte[] data,int size){    		try {				bos.write(data);				bos.flush();			} catch (IOException e) {				e.printStackTrace();			}    }    public native void startRecord();    public native void stopRecord();    public native void play();}

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布局文件：

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<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >	<Button android:id="@+id/start"	    android:layout_width="wrap_content"	    android:layout_height="wrap_content"	    android:text="用AudioRecord录音"/>	<Button android:id="@+id/stop"	    android:layout_width="wrap_content"	    android:layout_height="wrap_content"	    android:text="停止录音"/>	<Button android:id="@+id/play"	    android:layout_width="wrap_content"	    android:layout_height="wrap_content"	    android:text="用AudioTrack播放"/>	<Button android:id="@+id/stop"	    android:layout_width="wrap_content"	    android:layout_height="wrap_content"	    android:text="底层在录音哦，请点击我，我反应很快的耶，没有阻塞UI线程"/></LinearLayout>

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接下来是hello-jni.c:

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#include <malloc.h>#include <string.h>#include <jni.h>#include <android/log.h>#include <stdio.h>static JNIEnv* (*jni_env);static jbyteArray buffer;static jobject audio_track;static jint buffer_size;static jmethodID method_write;#define AUDIO_SOURCE_VOICE_COMMUNICATION (7)#define AUDIO_SOURCE_MIC (1)#define SAMPLE_RATE_IN_HZ (11025)#define CHANNEL_CONFIGURATION_MONO (16)#define ENCODING_PCM_16BIT (2)#define LOG_TAG "test"#define LOGI(f,v)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,f,v)#define LOGI2(a)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,a)static int run= 1;void  Java_com_example_hellojni_HelloJni_stopRecord(JNIEnv* jni_env,		jobject thiz){	run = 0;}void  Java_com_example_hellojni_HelloJni_startRecord(JNIEnv* jni_env,		jobject thiz){	jclass audio_record_class =(*jni_env)->FindClass(jni_env,"android/media/AudioRecord");	jmethodID constructor_id = (*jni_env)->GetMethodID(jni_env,audio_record_class, "<init>",				"(IIIII)V");	jmethodID min_buff_size_id = (*jni_env)->GetStaticMethodID(jni_env,audio_record_class,				"getMinBufferSize", "(III)I");	jint buff_size				= (*jni_env)->CallStaticIntMethod(jni_env,audio_record_class,						min_buff_size_id,						SAMPLE_RATE_IN_HZ,						CHANNEL_CONFIGURATION_MONO,						ENCODING_PCM_16BIT);	jobject audioRecord = (*jni_env)->NewObject(jni_env,audio_record_class, constructor_id,	//			AUDIO_SOURCE_MIC,				AUDIO_SOURCE_VOICE_COMMUNICATION,				SAMPLE_RATE_IN_HZ,				CHANNEL_CONFIGURATION_MONO,				ENCODING_PCM_16BIT,				buff_size);	LOGI2("startRecording");	jmethodID record_id = (*jni_env)->GetMethodID(jni_env,audio_record_class, "startRecording",				"()V");	//start recording	(*jni_env)->CallVoidMethod(jni_env,audioRecord, record_id);	LOGI2("after call startRecording");	jmethodID read_id = (*jni_env)->GetMethodID(jni_env,audio_record_class, "read", "([BII)I");	int nread = 0;	int blockSize = 100;	jbyteArray read_buff = (*jni_env)->NewByteArray(jni_env,blockSize);	jbyteArray aes_bytes = (*jni_env)->NewByteArray(jni_env,blockSize);	jbyte* audio_bytes;	FILE* fp = fopen("/sdcard/temp.pcm","ab");	LOGI2("after fopen");	//	jclass HelloJniCls =(*jni_env)->FindClass(jni_env,"com/example/hellojni/HelloJni");	jmethodID receiveAudioData = (*jni_env)->GetStaticMethodID(jni_env,HelloJniCls,"receiveAudioData",			"([BI)V");	while (run) {			nread = (*jni_env)->CallIntMethod(jni_env,audioRecord,read_id, read_buff, 0, blockSize);			if(nread<=0){				break;			}			audio_bytes = (jbyte*)calloc(nread,1);			(*jni_env)->GetByteArrayRegion(jni_env,read_buff, 0, nread,audio_bytes);//			fwrite(audio_bytes, 1, nread, fp);			(*jni_env)->CallStaticVoidMethod(jni_env,HelloJniCls, receiveAudioData, read_buff,nread);			usleep(50);	}}void  Java_com_example_hellojni_HelloJni_play(JNIEnv* jni_env,		jobject thiz){	  LOGI2("after Java_com_example_hellojni_HelloJni_play");//	(*jni_env) = jni_env;	jclass audio_track_cls = (*jni_env)->FindClass(jni_env,"android/media/AudioTrack");	jmethodID min_buff_size_id = (*jni_env)->GetStaticMethodID(										 jni_env,										 audio_track_cls,										"getMinBufferSize",										"(III)I");	buffer_size = (*jni_env)->CallStaticIntMethod(jni_env,audio_track_cls,min_buff_size_id,			    11025,			    2,			/*CHANNEL_CONFIGURATION_MONO*/				2);         /*ENCODING_PCM_16BIT*/	LOGI("buffer_size=%i",buffer_size);	buffer = (*jni_env)->NewByteArray(jni_env,buffer_size/4);	char buf[buffer_size/4];	jmethodID constructor_id = (*jni_env)->GetMethodID(jni_env,audio_track_cls, "<init>",			"(IIIIII)V");	audio_track = (*jni_env)->NewObject(jni_env,audio_track_cls,			constructor_id,			3, 			  /*AudioManager.STREAM_MUSIC*/			11025,        /*sampleRateInHz*/			2,			  /*CHANNEL_CONFIGURATION_MONO*/			2,			  /*ENCODING_PCM_16BIT*/			buffer_size,  /*bufferSizeInBytes*/			1			  /*AudioTrack.MODE_STREAM*/	);	//setvolume	LOGI2("setStereoVolume 1");	jmethodID setStereoVolume = (*jni_env)->GetMethodID(jni_env,audio_track_cls,"setStereoVolume","(FF)I");	(*jni_env)->CallIntMethod(jni_env,audio_track,setStereoVolume,1.0,1.0);	LOGI2("setStereoVolume 2");	//play    jmethodID method_play = (*jni_env)->GetMethodID(jni_env,audio_track_cls, "play",			"()V");    (*jni_env)->CallVoidMethod(jni_env,audio_track, method_play);    //write    method_write = (*jni_env)->GetMethodID(jni_env,audio_track_cls,"write","([BII)I");   FILE* fp = fopen("/sdcard/temp.pcm","rb");   LOGI2("after open");   int i=0;   while(!feof(fp)){	   jint read= fread(buf,sizeof(char),200,fp);	   (*jni_env)->SetByteArrayRegion(jni_env,buffer, 0,read, (jbyte *)buf);	   (*jni_env)->CallVoidMethod(jni_env,audio_track,method_write,buffer,0,read);   }}

编译文件:Android.mk:

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LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE    := hello-jniLOCAL_SRC_FILES := hello-jni.cLOCAL_LDLIBS := -L$(SYSROOT)/usr/lib -lloginclude $(BUILD_SHARED_LIBRARY)

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贴上效果图:

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例子中的调用思路:?? Activity->JNI API ->c??? c->JNI API->Activity?????

点击"用AudioRecord录音",启动了一条线程，该线程调用native方法startRecord，开始在native层启动录音。在录音的过程中，再将读取到的音频字节数组丢到java层。方法是：->(*jni_env)->CallStaticVoidMethod(jni_env,HelloJniCls, receiveAudioData, read_buff,nread);?? 然后在Activity中的静态方法?public static void receiveAudioData(byte[] data,int size){
?? ??? ??? ?try {
?? ??? ??? ??? ?bos.write(data);
?? ??? ??? ??? ?bos.flush();
?? ??? ??? ?} catch (IOException e) {
?? ??? ??? ??? ?e.printStackTrace();
?? ??? ??? ?}
??? }

中将数据写到文件.

至于用AudioTrack来播放的流程差不多，就不废话了。

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非常要注意的是在：

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startRecord.setOnClickListener(new OnClickListener() {
?? ??? ??? [email protected]
?? ??? ??? ?public void onClick(View v) {
?? ??? ??? ??? ?new Thread(){
?? ??? ??? ??? ??? ?public void run(){

?? ??? ??? ??? ??? ??? ?initOutputStream();

?? ??? ??? ??? ??? ??? ?startRecord();
?? ??? ??? ??? ??? ?}
?? ??? ??? ??? ?}.start();

?? ??? ??? ?}
?? ??? ?});

这里要写个线程，很重要！！！！ ，不然会阻塞UI线程的！！！

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做这个例子是做一个远程会议产品中要用到底层录音，由于项目中开启录音导致界面很卡，所以通过这个例子找到了原因，那就是录音模块没有在一个非UI线程中运行，导致阻塞UI.

转载自：http://blog.csdn.net/liuxiit/article/details/7915513