Android本地视频播放器开发 - 搜索本地视频（1）

　这一章的主要内容是搜索手机本地视频，添加到ListView列表里，每一个表项含有这个视频的缩略图，视频的播放时间，视频的标题，在搜索本地视频（1）中我们先制作搜索功能。
 
Video.java--视频相关的属性类

　　package com.zhangjie.graduation.videopalyer.videofile;

　　import java.io.Serializable;

　　import com.zhangjie.graduatioponent.LoadedImage;

　　public class Video implements Serializable{
    /**
  * 
  */
 private static final long serialVersionUID = -7920222595800367956L;
 private int id;
    private String title;
    private String album;
    private String artist;
    private String displayName;
    private String mimeType;
    private String path;
    private long size;
    private long duration;
    private LoadedImage image;

　　/**
    * 
    */
    public Video() {
        super();
    }

　　/**
    * @param id
    * @param title
    * @param album
    * @param artist
    * @param displayName
    * @param mimeType
    * @param data
    * @param size
    * @param duration
    */
    public Video(int id, String title, String album, String artist,
            String displayName, String mimeType, String path, long size,
            long duration) {
        super();
        this.id = id;
        this.title = title;
        this.album = album;
        this.artist = artist;
        this.displayName = displayName;
        this.mimeType = mimeType;
        this.path = path;
        this.size = size;
        this.duration = duration;
    }

　　public int getId() {
        return id;
    }

　　public void setId(int id) {
        this.id = id;
    }

　　public String getTitle() {
        return title;
    }

　　public void setTitle(String title) {
        this.title = title;
    }

　　public String getAlbum() {
        return album;
    }

　　public void setAlbum(String album) {
        this.album = album;
    }

　　public String getArtist() {
        return artist;
    }

　　public void setArtist(String artist) {
        this.artist = artist;
    }

　　public String getDisplayName() {
        return displayName;
    }

　　public void setDisplayName(String displayName) {
        this.displayName = displayName;
    }

　　public String getMimeType() {
        return mimeType;
    }

　　public void setMimeType(String mimeType) {
        this.mimeType = mimeType;
    }

　　public String getPath() {
        return path;
    }

　　public void setPath(String path) {
        this.path = path;
    }

　　public long getSize() {
        return size;
    }

　　public void setSize(long size) {
        this.size = size;
    }

　　public long getDuration() {
        return duration;
    }

　　public void setDuration(long duration) {
        this.duration = duration;
    }
    
    public LoadedImage getImage(){
     return image;

  
     }
     
     public void setImage(LoadedImage image){
      this.image = image;
     }
 
  
 　　}
 
  
 　　AbstructProvider.java ---一个接口，来获取搜索的视频的一个集合
 package com.zhangjie.graduation.videopalyer.videofile;
 
  
 　　import java.util.List;
 
  
 　　public interface AbstructProvider {
  
     public List
 
  
 　　VideoProvider.java--- 实现AbstructProvider接口，通过cursor来搜索视频的相关信息
 package com.zhangjie.graduation.videopalyer.videofile;
 
  
 　　import java.util.ArrayList;
 import java.util.List;
 
  
 　　import ntent.Context;
 import android.database.Cursor;
 import android.provider.MediaStore;
 
  
 　　public class VideoProvider implements AbstructProvider {
     private Context context;
     
     public VideoProvider(Context context) {
         ntext = context;
     }
     
     @Override
     public List
 
  
 　　}
 
  
 　　最后在主类中使用如下代码来获取最终得到的视频相关信息集合
 
  
 　　AbstructProvider provider = new VideoProvider(this);
 List
 
  
 　　在上面的listVideos包含了本地所有的视频的相关信息，下一章将会用到listVideos数据。
 
  
 　　在Android本地视频播放器开发--搜索本地视频（1） ;中我们获取了本地视频的数据，在这一章里面，我们将获取的数据通过LIstView来动态的实现出来。
 
  
 　　1、首先介绍布局代码，主布局代码只含有一个LIstView  --jie_video.xml
 
  
 　　
      android:layout_width="match_parent"
     android:layout_height="match_parent" >
     android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:layout_alignParentBottom="true"
   android:id="@+id/jievideolistfile"
  />
 
 
  
 　　2、下一个布局就是listView的子项的布局
 
  
 　　
      android:layout_width="match_parent"
     android:layout_height="wrap_content" >
              android:layout_width="120dp"
         android:layout_height="80dp"
         android:id="@+id/video_img"
         android:contentDescription="@string/cont"
         />
              android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:layout_toRightOf="@id/video_img"
     android:layout_alignBottom="@id/video_img"
         >
                android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:id="@+id/video_title"
       android:gravity="center"
       android:layout_marginTop="5dp"
       android:text="@string/title"
     />
         
          android:layout_width="match_parent"
       android:layout_height="wrap_content"
       android:id="@+id/video_time"
       android:gravity="center"
       android:layout_alignParentBottom="true"
       android:layout_marginBottom="5dp"
       android:text="@string/time"
     />
     
 
 
  
 　　3、布局都写好了，然后就是Activity的编写，这里涉及到视频的缩略图的显示，所以要用到异步加载功能
 
  
 　　JieVideo.java
 
  
 　　package com.zhangjie.graduation.videopalyer;
 
  
 　　import java.util.List;
 
  
 　　import com.zhangjie.graduatioponent.JieVideoListViewAdapter;
 import com.zhangjie.graduatioponent.LoadedImage;
 import com.zhangjie.graduation.videopalyer.videofile.AbstructProvider;
 import com.zhangjie.graduation.videopalyer.videofile.Video;
 import com.zhangjie.graduation.videopalyer.videofile.VideoProvider;
 
  
 　　import android.app.Activity;
 import ntent.Intent;
 import android.graphics.Bitmap;
 import android.graphics.drawable.BitmapDrawable;
 import dia.ThumbnailUtils;
 import android.os.AsyncTask;
 import android.os.Bundle;
 import android.provider.MediaStore.Video.Thumbnails;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.ImageView;
 import android.widget.ListView;
 import android.widget.AdapterView.OnItemClickListener;
 
  
 　　public class JieVideo extends Activity{
 
  
 　　public JieVideo instance = null;
  ListView mJieVideoListView;
  JieVideoListViewAdapter mJieVideoListViewAdapter;
  List
 
  
 　　for (int i = 0; i < count; i++) {
    final ImageView v = (ImageView) grid.getChildAt(i);
    list[i] = new LoadedImage(
      ((BitmapDrawable) v.getDrawable()).getBitmap());
   }
 
  
 　　return list;
  }
  /** 
     * 获取视频缩略图 
     * @param videoPath 
     * @param width 
     * @param height 
     * @param kind 
     * @return 
     */  
     private Bitmap getVideoThumbnail(String videoPath, int width , int height, int kind){  
     Bitmap bitmap = null;  
     bitmap = ThumbnailUtils.createVideoThumbnail(videoPath, kind);  
     bitmap = ThumbnailUtils.extractThumbnail(bitmap, width, height, ThumbnailUtils.OPTIONS_RECYCLE_INPUT);  
     return bitmap;  
     } 
 
  
 　　class LoadImagesFromSDCard extends AsyncTask {
   @Override
   protected Object doInBackground(Object... params) {
    Bitmap bitmap = null;
    for (int i = 0; i < videoSize; i++) {
     bitmap = getVideoThumbnail(listVideos.get(i).getPath(), 120, 120, Thumbnails.MINI_KIND);
     if (bitmap != null) {
      publishProgress(new LoadedImage(bitmap));
     }
    }
    return null;
   }
   
   @Override
   public void onProgressUpdate(LoadedImage... value) {
    addImage(value);
   }
  }
  }
 
  
 　　4、上面还涉及一个就是LIstView的适配器，这里是继承BaseAdapter。
 
  
 　　JieVideoListViewAdapter.java
 
  
 　　package com.zhangjie.graduatioponent;
 
  
 　　import java.util.ArrayList;
 import java.util.List;
 
  
 　　import com.zhangjie.graduation.videopalyer.R;
 import com.zhangjie.graduation.videopalyer.videofile.Video;
 
  
 　　import ntent.Context;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.BaseAdapter;
 import android.widget.ImageView;
 import android.widget.TextView;
 
  
 　　public class JieVideoListViewAdapter extends BaseAdapter{
 
  
 　　List
 
  
 　　@Override
  public View getView(int position, View convertView, ViewGroup parent) {
   ViewHolder holder = null;
   if (convertView == null) {
    holder = new ViewHolder();
    convertView = mLayoutInflater.inflate(R.layout.video_list_view, null);
    holder.img = (ImageView)convertView.findViewById(R.id.video_img);
    holder.title = (TextView)convertView.findViewById(R.id.video_title);
    holder.time = (TextView)convertView.findViewById(R.id.video_time);
    convertView.setTag(holder);
   }else {
    holder = (ViewHolder)convertView.getTag();
   }
    holder.title.setText(listVideos.get(position).getTitle());//ms
    long min = listVideos.get(position).getDuration() /1000 / 60;
    long sec = listVideos.get(position).getDuration() /1000 % 60;
    holder.time.setText(min+" : "+sec);
    holder.img.setImageBitmap(photos.get(position).getBitmap());
   
   return convertView;
  }
 
  
 　　public final class ViewHolder{
   public ImageView img;
   public TextView title;
   public TextView time;
  }
 }
 
  
 　　5、还有一个在JieVideo类中使用了一个LoadedImage的类，它的代码如下：
 
  
 　　package com.zhangjie.graduatioponent;
 
  
 　　import android.graphics.Bitmap;
 
  
 　　public class LoadedImage {
   Bitmap mBitmap;
 
  
 　　public LoadedImage(Bitmap bitmap) {
   mBitmap = bitmap;
  }
 
  
 　　public Bitmap getBitmap() {
   return mBitmap;
  }
 }
 
  
 　　那就看看最终的实现效果吧：
 
  
 　　
 
  
 　　在Android本地视频播放器开发中的搜索本地视频章节中，我们能够搜索本地视频并且显示每个视频的图片、标题、时间长度，当然如果需要添加其他的例如视频的长度和宽度可以使用Video类中的方法，既然我们获取到视频后，那么接下来就是解码视频，解码视频我使用的是ffmpeg，所以这张就是使用NDK编译手机可以使用的FFmpeg库。
 
  
 　　首先到官网下载最新的源码,然后在ffmpeg目录下面创建一个脚本config.sh，内容如下:
 
  
 　　NDK=/opt/android-ndk-r8d
 PLATFORM=$NDK/platforms/android-8/arch-arm/
 PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
 LOCAL_ARM_NEON=true
 CPU=armv7-a
 OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -mcpu=cortex-a8"
 PREFIX=./android/$CPU
 ./configure --target-os=linux \
     --prefix=$PREFIX \
     --enable-cross-compile \
     --arch=arm \
     --enable-nonfree \
     --enable-asm \
     --cpu=cortex-a8 \
     --enable-neon \
     --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
     --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
     --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
     --sysroot=$PLATFORM \
     --extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 $OPTIMIZE_CFLAGS " \
     --disable-shared \
     --enable-static \
     --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -nostdlib -lc -lm -ldl -llog" \
     --disable-ffmpeg \
     --disable-ffplay \
     --disable-ffprobe \
     --disable-ffserver \
     --disable-swscale \
     --disable-swresample \
     --enable-avformat \
     --enable-avcodec \
     --disable-optimizations \
     --disable-debug \
     --disable-doc \
     --disable-stripping \
     --enable-pthreads \
     --disable-yasm \
     --enable-zlib \
     --enable-pic \
     --enable-small
 
  
 　　make clean
 make  -j4 install
 
  
 　　$PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
 
  
 　　$PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg-neon.so -shared -nostdlib  -z noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg-neon.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a
 
  
 　　注意上面的NDK要换成你本地的路径。这个脚本我是启用neon的，所以只能运行在有neon的手机上，如果想要运行到非neon的手机上，则需要去掉neon特性。
 
  
 　　然后执行这个脚本，就会生成libffmpeg-neon.so
 
  
 　　在下一张中会使用ffmpeg解码视频文件中音频。
 
  
 　　在上一章中Android本地视频播放器开发--NDK编译FFmpeg能够获取编译出来的ffmpeg库（见 ），接下来就是调用ffmpeg来实现解码，这里我们先解码音频，然后在播放音频，同时为了适应性我会用不同的方法进行播放例如使用Android提供的AudioTrack，SDL、OpengAL,OpenSL ES，最终合入视频播放器的是OpenSL ES，这样可以减少CPU的利用率。接下来在这一章中，先简单的介绍如何解码音频，在下一章中，实现音频的播放。
  
 首先就是编写调用ffmpeg的文件这里命名为:Decodec_Audio.c
 
  
 　　#include 
 #include 
 
  
 　　#include 
 
  
 　　#include "VideoPlayerDecode.h"
 #include "../ffmpeg/libavutil/avutil.h"
 #include "../ffmpeg/libavcodec/avcodec.h"
 #include "../ffmpeg/libavformat/avformat.h"
 
  
 　　#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "graduation", __VA_ARGS__))
 
  
 　　AVFormatContext *pFormatCtx = NULL;
 int            audioStream, delay_time, videoFlag = 0;
 AVCodecContext  *aCodecCtx;
 AVCodec        *aCodec;
 AVFrame        *aFrame;
 AVPacket        packet;
 int  frameFinished = 0;
 
  
 　　JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayer
 (JNIEnv *env, jclass clz, jstring fileName)
 {
  const char* local_title = (*env)->GetStringUTFChars(env, fileName, NULL);
  av_register_all();//注册所有支持的文件格式以及编解码器
  /*
   *只读取文件头，并不会填充流信息
   */
  if(avformat_open_input(&pFormatCtx, local_title, NULL, NULL) != 0)
   return -1;
  /*
   *获取文件中的流信息，此函数会读取packet，并确定文件中所有流信息，
   *设置pFormatCtx->streams指向文件中的流，但此函数并不会改变文件指针，
   *读取的packet会给后面的解码进行处理。
   */
  if(avformat_find_stream_info(pFormatCtx, NULL) < 0)
   return -1;
  /*
   *输出文件的信息，也就是我们在使用ffmpeg时能够看到的文件详细信息，
   *第二个参数指定输出哪条流的信息，-1代表ffmpeg自己选择。最后一个参数用于
   *指定dump的是不是输出文件，我们的dump是输入文件，因此一定要为0
   */
  av_dump_format(pFormatCtx, -1, local_title, 0);
  int i = 0;
  for(i=0; i< pFormatCtx->nb_streams; i++)
  {
   if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO){
    audioStream = i;
    break;
   }
  }
 
  
 　　if(audioStream < 0)return -1;
  aCodecCtx = pFormatCtx->streams[audioStream]->codec;
  aCodec = avcodec_find_decoder(aCodecCtx->codec_id);
  if(avcodec_open2(aCodecCtx, aCodec, NULL) < 0)return -1;
  aFrame = avcodec_alloc_frame();
  if(aFrame == NULL)return -1;
  int ret;
  while(videoFlag != -1)
  {
   if(av_read_frame(pFormatCtx, &packet) < 0)break;
   if(packet.stream_index == audioStream)
   {
    ret = avcodec_decode_audio4(aCodecCtx, aFrame, &frameFinished, &packet);
    if(ret > 0 && frameFinished)
    {
     int data_size = av_samples_get_buffer_size(
       aFrame->linesize,aCodecCtx->channels,
       aFrame->nb_samples,aCodecCtx->sample_fmt, 0);
     LOGI("audioDecodec  :%d",data_size);
    }
 
  
 　　}
   usleep(50000);
   while(videoFlag != 0)
   {
    if(videoFlag == 1)//暂停
    {
     sleep(1);
    }else if(videoFlag == -1) //停止
    {
     break;
    }
   }
   av_free_packet(&packet);
  }
  av_free(aFrame);
  avcodec_close(aCodecCtx);
  avformat_close_input(&pFormatCtx);
  (*env)->ReleaseStringUTFChars(env, fileName, local_title);
 }
 
  
 　　JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayerPauseOrPlay
   (JNIEnv *env, jclass clz)
 {
         if(videoFlag == 1)
         {
                 videoFlag = 0;
         }else if(videoFlag == 0){
                 videoFlag = 1;
         }
         return videoFlag;
 }
 
  
 　　JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayerStop
   (JNIEnv *env, jclass clz)
 {
         videoFlag = -1;
 }
 
  
 　　接下来就是编写Android.mk:
 
  
 　　#######################################################
 ##########              ffmpeg-prebuilt        #######
 #######################################################
 #declare the prebuilt library
 include $(CLEAR_VARS)
 LOCAL_MODULE := ffmpeg-prebuilt
 LOCAL_SRC_FILES := ffmpeg/android/armv7-a/libffmpeg-neon.so
 LOCAL_EXPORT_C_INCLUDES := ffmpeg/android/armv7-a/include
 LOCAL_EXPORT_LDLIBS := ffmpeg/android/armv7-a/libffmpeg-neon.so
 LOCAL_PRELINK_MODULE := true
 include $(PREBUILT_SHARED_LIBRARY)
 
  
 　　########################################################
 ##              ffmpeg-test-neno.so            ########
 ########################################################
 include $(CLEAR_VARS)
 TARGET_ARCH_ABI=armeabi-v7a
 LOCAL_ARM_MODE=arm
 LOCAL_ARM_NEON=true
 LOCAL_ALLOW_UNDEFINED_SYMBOLS=false
 LOCAL_MODULE := ffmpeg-test-neon
 LOCAL_SRC_FILES := jniffmpeg/Decodec_Audio.c
 
  
 　　LOCAL_C_INCLUDES := $(LOCAL_PATH)/ffmpeg/android/armv7-a/include \
                     $(LOCAL_PATH)/ffmpeg \
                     $(LOCAL_PATH)/ffmpeg/libavutil \
                     $(LOCAL_PATH)/ffmpeg/libavcodec \
                     $(LOCAL_PATH)/ffmpeg/libavformat \
                     $(LOCAL_PATH)/ffmpeg/libavcodec \
                     $(LOCAL_PATH)/ffmpeg/libswscale \
                     $(LOCAL_PATH)/jniffmpeg \
                     $(LOCAL_PATH)
 LOCAL_SHARED_LIBRARY := ffmpeg-prebuilt
 LOCAL_LDLIBS    := -llog -ljnigraphics -lz -lm $(LOCAL_PATH)/ffmpeg/android/armv7-a/libffmpeg-neon.so
 include $(BUILD_SHARED_LIBRARY)
 
  
 　　然后在终端运行ndk-build,运行结果如下:
 
  
 　　root@zhangjie:/Graduation/jni# ndk-build
 Install        : libffmpeg-neon.so => libs/armeabi/libffmpeg-neon.so
 Compile arm    : ffmpeg-test-neon <= Decodec_Audio.c
 SharedLibrary  : libffmpeg-test-neon.so
 Install        : libffmpeg-test-neon.so => libs/armeabi/libffmpeg-test-neon.so
 
  
 　　把编译出来的
 
  
 　　libffmpeg-test-neon.so
 
  
 　　libffmpeg-neon.so
 
  
 　　拷贝到之前android功能下的libs/armeabi目录下面，点击视频，视频文件开始解码音频，当解码成功，则打印出解码音频包的大小：
 
  
 　　06-07 04:51:30.953: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.000: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.109: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.156: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.257: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.304: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.406: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.460: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:31.554: I/graduation(7014): audioDecodec  :2048
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 06-07 04:51:32.367: I/graduation(7014): audioDecodec  :2048
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 06-07 04:51:32.515: I/graduation(7014): audioDecodec  :2048
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 06-07 04:51:32.671: I/graduation(7014): audioDecodec  :2048
 06-07 04:51:32.773: I/graduation(7014): audioDecodec  :2048
 
  
 　　在logcat里面可以看到解码音频成功，下面一章我们将解码出来的音频进行播放。
 
  
 　　在Android本地视频播放器开发--ffmpeg解码视频文件中的音频(1)【】中我们从视频文件中解码出音频，这一章中将使用OpenSL ES来播放解码的音频数据，首先关于OpenSL ES这里暂不介绍，可以查看官网以及NDK中samples下面的native-audio里面的文件，这里我也是扣取了其中的代码，我们播放音频的部分在上一章的基础上进行添加的，代码如下:
 
  
 　　#include 
 #include 
 #include 
 
  
 　　#include 
 #include 
 
  
 　　// for native audio
 #include 
 #include 
 
  
 　　#include "VideoPlayerDecode.h"
 #include "../ffmpeg/libavutil/avutil.h"
 #include "../ffmpeg/libavcodec/avcodec.h"
 #include "../ffmpeg/libavformat/avformat.h"
 
  
 　　#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "graduation", __VA_ARGS__))
 
  
 　　AVFormatContext *pFormatCtx = NULL;
 int            audioStream, delay_time, videoFlag = 0;
 AVCodecContext  *aCodecCtx;
 AVCodec        *aCodec;
 AVFrame        *aFrame;
 AVPacket        packet;
 int  frameFinished = 0;
 
  
 　　// engine interfaces
 static SLObjectItf engineObject = NULL;
 static SLEngineItf engineEngine;
 
  
 　　// output mix interfaces
 static SLObjectItf outputMixObject = NULL;
 static SLEnvironmentalReverbItf outputMixEnvironmentalReverb = NULL;
 
  
 　　// buffer queue player interfaces
 static SLObjectItf bqPlayerObject = NULL;
 static SLPlayItf bqPlayerPlay;
 static SLAndroidSimpleBufferQueueItf bqPlayerBufferQueue;
 static SLEffectSendItf bqPlayerEffectSend;
 static SLMuteSoloItf bqPlayerMuteSolo;
 static SLVolumeItf bqPlayerVolume;
 
  
 　　// aux effect on the output mix, used by the buffer queue player
 static const SLEnvironmentalReverbSettings reverbSettings =
     SL_I3DL2_ENVIRONMENT_PRESET_STONECORRIDOR;
 
  
 　　// file descriptor player interfaces
 static SLObjectItf fdPlayerObject = NULL;
 static SLPlayItf fdPlayerPlay;
 static SLSeekItf fdPlayerSeek;
 static SLMuteSoloItf fdPlayerMuteSolo;
 static SLVolumeItf fdPlayerVolume;
 
  
 　　// pointer and size of the next player buffer to enqueue, and number of remaining buffers
 static short *nextBuffer;
 static unsigned nextSize;
 static int nextCount;
 
  
 　　// this callback handler is called every time a buffer finishes playing
 void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
 {
     assert(bq == bqPlayerBufferQueue);
     assert(NULL == context);
     // for streaming playback, replace this test by logic to find and fill the next buffer
     if (--nextCount > 0 && NULL != nextBuffer && 0 != nextSize) {
         SLresult result;
         // enqueue another buffer
         result = (*bqPlayerBufferQueue)->Enqueue(bqPlayerBufferQueue, nextBuffer, nextSize);
         // the most likely other result is SL_RESULT_BUFFER_INSUFFICIENT,
         // which for this code example would indicate a programming error
         assert(SL_RESULT_SUCCESS == result);
     }
 }
 
  
 　　void createEngine(JNIEnv* env, jclass clazz)
 {
  SLresult result;
 
  
 　　// create engine
     result = slCreateEngine(&engineObject, 0, NULL, 0, NULL, NULL);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// realize the engine
     result = (*engineObject)->Realize(engineObject, SL_BOOLEAN_FALSE);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// get the engine interface, which is needed in order to create other objects
     result = (*engineObject)->GetInterface(engineObject, SL_IID_ENGINE, &engineEngine);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// create output mix, with environmental reverb specified as a non-required interface
     const SLInterfaceID ids[1] = {SL_IID_ENVIRONMENTALREVERB};
     const SLboolean req[1] = {SL_BOOLEAN_FALSE};
     result = (*engineEngine)->CreateOutputMix(engineEngine, &outputMixObject, 1, ids, req);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// realize the output mix
     result = (*outputMixObject)->Realize(outputMixObject, SL_BOOLEAN_FALSE);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// get the environmental reverb interface
     // this could fail if the environmental reverb effect is not available,
     // either because the feature is not present, excessive CPU load, or
     // the required MODIFY_AUDIO_SETTINGS permission was not requested and granted
     result = (*outputMixObject)->GetInterface(outputMixObject, SL_IID_ENVIRONMENTALREVERB,
             &outputMixEnvironmentalReverb);
     if (SL_RESULT_SUCCESS == result) {
         result = (*outputMixEnvironmentalReverb)->SetEnvironmentalReverbProperties(
                 outputMixEnvironmentalReverb, &reverbSettings);
     }
     // ignore unsuccessful result codes for environmental reverb, as it is optional for this example
 }
 
  
 　　void createBufferQueueAudioPlayer(JNIEnv* env, jclass clazz, int rate, int channel,int bitsPerSample)
 {
  SLresult result;
 
  
 　　// configure audio source
     SLDataLocator_AndroidSimpleBufferQueue loc_bufq = {SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE, 2};
 //    SLDataFormat_PCM format_pcm = {SL_DATAFORMAT_PCM, 2, SL_SAMPLINGRATE_16,
 //        SL_PCMSAMPLEFORMAT_FIXED_16, SL_PCMSAMPLEFORMAT_FIXED_16,
 //        SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT, SL_BYTEORDER_LITTLEENDIAN};
   SLDataFormat_PCM format_pcm;
   format_pcm.formatType = SL_DATAFORMAT_PCM;
 format_pcm.numChannels = channel;
 format_pcm.samplesPerSec = rate * 1000;
  format_pcm.bitsPerSample = bitsPerSample;
  ntainerSize = 16;
 if(channel == 2)
 format_pcm.channelMask = SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT;
 else
 format_pcm.channelMask = SL_SPEAKER_FRONT_CENTER;
 format_pcm.endianness = SL_BYTEORDER_LITTLEENDIAN;
     SLDataSource audioSrc = {&loc_bufq, &format_pcm};
 
  
 　　// configure audio sink
     SLDataLocator_OutputMix loc_outmix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObject};
     SLDataSink audioSnk = {&loc_outmix, NULL};
 
  
 　　// create audio player
     const SLInterfaceID ids[3] = {SL_IID_BUFFERQUEUE, SL_IID_EFFECTSEND,
             /*SL_IID_MUTESOLO,*/ SL_IID_VOLUME};
     const SLboolean req[3] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE,
             /*SL_BOOLEAN_TRUE,*/ SL_BOOLEAN_TRUE};
     result = (*engineEngine)->CreateAudioPlayer(engineEngine, &bqPlayerObject, &audioSrc, &audioSnk,
             3, ids, req);
     assert(SL_RESULT_SUCCESS == result);
 // realize the player
     result = (*bqPlayerObject)->Realize(bqPlayerObject, SL_BOOLEAN_FALSE);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// get the play interface
     result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_PLAY, &bqPlayerPlay);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// get the buffer queue interface
     result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_BUFFERQUEUE,
             &bqPlayerBufferQueue);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// register callback on the buffer queue
     result = (*bqPlayerBufferQueue)->RegisterCallback(bqPlayerBufferQueue, bqPlayerCallback, NULL);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// get the effect send interface
     result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_EFFECTSEND,
             &bqPlayerEffectSend);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　#if 0  // mute/solo is not supported for sources that are known to be mono, as this is
     // get the mute/solo interface
     result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_MUTESOLO, &bqPlayerMuteSolo);
     assert(SL_RESULT_SUCCESS == result);
 #endif
 
  
 　　// get the volume interface
     result = (*bqPlayerObject)->GetInterface(bqPlayerObject, SL_IID_VOLUME, &bqPlayerVolume);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　// set the player's state to playing
     result = (*bqPlayerPlay)->SetPlayState(bqPlayerPlay, SL_PLAYSTATE_PLAYING);
     assert(SL_RESULT_SUCCESS == result);
 
  
 　　}
 
  
 　　void AudioWrite(const void*buffer, int size)
 {
  (*bqPlayerBufferQueue)->Enqueue(bqPlayerBufferQueue, buffer, size);
 }
 
  
 　　JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayer
 (JNIEnv *env, jclass clz, jstring fileName)
 {
  const char* local_title = (*env)->GetStringUTFChars(env, fileName, NULL);
  av_register_all();//注册所有支持的文件格式以及编解码器
  /*
   *只读取文件头，并不会填充流信息
   */
  if(avformat_open_input(&pFormatCtx, local_title, NULL, NULL) != 0)
   return -1;
  /*
   *获取文件中的流信息，此函数会读取packet，并确定文件中所有流信息，
   *设置pFormatCtx->streams指向文件中的流，但此函数并不会改变文件指针，
   *读取的packet会给后面的解码进行处理。
   */
  if(avformat_find_stream_info(pFormatCtx, NULL) < 0)
   return -1;
  /*
   *输出文件的信息，也就是我们在使用ffmpeg时能够 到的文件详细信息，
   *第二个参数指定输出哪条流的信息，-1代表ffmpeg自己选择。最后一个参数用于
   *指定dump的是不是输出文件，我们的dump是输入文件，因此一定要为0
   */
  av_dump_format(pFormatCtx, -1, local_title, 0);
  int i = 0;
  for(i=0; i< pFormatCtx->nb_streams; i++)
  {
   if(pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO){
    audioStream = i;
    break;
   }
  }
 
  
 　　if(audioStream < 0)return -1;
  aCodecCtx = pFormatCtx->streams[audioStream]->codec;
  aCodec = avcodec_find_decoder(aCodecCtx->codec_id);
  if(avcodec_open2(aCodecCtx, aCodec, NULL) < 0)return -1;
  aFrame = avcodec_alloc_frame();
  if(aFrame == NULL)return -1;
  int ret;
  createEngine(env, clz);
  int flag_start = 0;
  while(videoFlag != -1)
  {
   if(av_read_frame(pFormatCtx, &packet) < 0)break;
   if(packet.stream_index == audioStream)
   {
    ret = avcodec_decode_audio4(aCodecCtx, aFrame, &frameFinished, &packet);
    if(ret > 0 && frameFinished)
    {
     if(flag_start == 0)
     {
      flag_start = 1;
      createBufferQueueAudioPlayer(env, clz, aCodecCtx->sample_rate, aCodecCtx->channels, SL_PCMSAMPLEFORMAT_FIXED_16);
     }
     int data_size = av_samples_get_buffer_size(
       aFrame->linesize,aCodecCtx->channels,
       aFrame->nb_samples,aCodecCtx->sample_fmt, 1);
     LOGI("audioDecodec  :%d : %d, :%d    :%d",data_size,aCodecCtx->channels,aFrame->nb_samples,aCodecCtx->sample_rate);
     (*bqPlayerBufferQueue)->Enqueue(bqPlayerBufferQueue, aFrame->data[0], data_size);
    }
 
  
 　　}
   usleep(5000);
   while(videoFlag != 0)
   {
    if(videoFlag == 1)//暂停
    {
     sleep(1);
    }else if(videoFlag == -1) //停止
    {
     break;
    }
   }
   av_free_packet(&packet);
  }
  av_free(aFrame);
  avcodec_close(aCodecCtx);
  avformat_close_input(&pFormatCtx);
  (*env)->ReleaseStringUTFChars(env, fileName, local_title);
 }
 
  
 　　JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayerPauseOrPlay
   (JNIEnv *env, jclass clz)
 {
         if(videoFlag == 1)
         {
                 videoFlag = 0;
         }else if(videoFlag == 0){
                 videoFlag = 1;
         }
         return videoFlag;
 }
 
  
 　　JNIEXPORT jint JNICALL Java_com_zhangjie_graduation_videopalyer_jni_VideoPlayerDecode_VideoPlayerStop
   (JNIEnv *env, jclass clz)
 {
         videoFlag = -1;
 }
 
  
 　　然后就是需要在Android.mk中添加OpenSL ES的库支持，代码如下:
 
  
 　　LOCAL_PATH := $(call my-dir)
 #######################################################
 ##########  ffmpeg-prebuilt  #######
 #######################################################
 #declare the prebuilt library
 include $(CLEAR_VARS)
 LOCAL_MODULE := ffmpeg-prebuilt
 LOCAL_SRC_FILES := ffmpeg/android/armv7-a/libffmpeg-neon.so
 LOCAL_EXPORT_C_INCLUDES := ffmpeg/android/armv7-a/include
 LOCAL_EXPORT_LDLIBS := ffmpeg/android/armv7-a/libffmpeg-neon.so
 LOCAL_PRELINK_MODULE := true
 include $(PREBUILT_SHARED_LIBRARY)
 
  
 　　########################################################
 ##  ffmpeg-test-neno.so  ########
 ########################################################
 include $(CLEAR_VARS)
 TARGET_ARCH_ABI=armeabi-v7a
 LOCAL_ARM_MODE=arm
 LOCAL_ARM_NEON=true
 LOCAL_ALLOW_UNDEFINED_SYMBOLS=false
 LOCAL_MODULE := ffmpeg-test-neon
 #LOCAL_SRC_FILES := jniffmpeg/VideoPlayerDecode.c
 LOCAL_SRC_FILES := jniffmpeg/Decodec_Audio.c 
 
  
 　　LOCAL_C_INCLUDES := $(LOCAL_PATH)/ffmpeg/android/armv7-a/include \
       $(LOCAL_PATH)/ffmpeg \
       $(LOCAL_PATH)/ffmpeg/libavutil \
       $(LOCAL_PATH)/ffmpeg/libavcodec \
       $(LOCAL_PATH)/ffmpeg/libavformat \
       $(LOCAL_PATH)/ffmpeg/libavcodec \
       $(LOCAL_PATH)/ffmpeg/libswscale \
       $(LOCAL_PATH)/jniffmpeg \
       $(LOCAL_PATH)
 LOCAL_SHARED_LIBRARY := ffmpeg-prebuilt
 LOCAL_LDLIBS    := -llog -lGLESv2 -ljnigraphics -lz -lm $(LOCAL_PATH)/ffmpeg/android/armv7-a/libffmpeg-neon.so
 LOCAL_LDLIBS    += -lOpenSLES 
 include $(BUILD_SHARED_LIBRARY)
 
  
 　　由于OpenSLES最低版本需要9所以要在Application.mk中添加平台
 
  
 　　# The ARMv7 is significanly faster due to the use of the hardware FPU
 APP_ABI := armeabi 
 APP_PLATFORM := android-9
 APP_STL := stlport_static
 APP_CPPFLAGS += -fno-rtti
 #APP_ABI := armeabi
 
  
 　　最后在终端运行ndk-build,就会将代码添加到
 
  
 　　ffmpeg-test-neon.so这个库中
 
  
 　　最后在Android端调用
 
  
 　　VideoPlayer这个函数就会自动播放视频的声音，测试发现虽然声音正常但是有杂音，可能采样率设置的不对，获取其他的配置有问题，下一章着重解决这个问题，同时使用队列的方式来从视频中取音频包，然后从音频包队列中取出，然后解码播放。
 
  
 　　在上一章  Android本地视频播放器开发--ffmpeg解码视频文件中的音频(2)【】中使用OpenSL ES来播放视频的声音，遗留的问题是声音的不同步，由于视频实现部分也要同步，而且音视频也要同步，所以音频部分就不单独同步问题，当同时播放音视频的时候进行两者的同步问题，对于视频显示部分最后是要使用OpenGL es来实现，由于SDL可以和OpenGL ES进行搭配，所以使用SDL+OpenGL ES进行显示视频，所以这章将要讲解的是SDL的交叉编译.
 
  
 　　一、到官网下载下载2.0的源码也可以通过hg来clone最新的源码
 
  
 　　hg clone
 
  
 　　二、其实1.3以后的版本就添加了android的支持，所以下载完源码后，在SDL目录下创建一个jni的目录，然后将原先SDL目录下面的文件以及文件夹都拷贝到jni目录下面，在jni目录下面我们会看见一个android.mk的文件,这就是官方给我们编写的编译文件，由于手机基本上都是使用的arm编译器，所以我在里面添加了LOCAL_ARM_MODE=arm，模块的编译使用arm编译器来编译，具体的内容如下:
 
  
 　　###########################
 #
 # SDL shared library
 #
 ###########################
 
  
 　　include $(CLEAR_VARS)
 
  
 　　LOCAL_MODULE := SDL2
 LOCAL_ARM_MODE=arm
 LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
 
  
 　　LOCAL_SRC_FILES := \
         $(subst $(LOCAL_PATH)/,, \
         $(wildcard $(LOCAL_PATH)/src/*.c) \
         $(wildcard $(LOCAL_PATH)/src/audio/*.c) \
         $(wildcard $(LOCAL_PATH)/src/audio/android/*.c) \
         $(wildcard $(LOCAL_PATH)/src/audio/dummy/*.c) \
         $(LOCAL_PATH)/src/atomic/SDL_atomic.c \
         $(LOCAL_PATH)/src/atomic/SDL_spinlock.c.arm \
         $(wildcard $(LOCAL_PATH)/src/core/android/*.cpp) \
         $(wildcard $(LOCAL_PATH)/src/cpuinfo/*.c) \
         $(wildcard $(LOCAL_PATH)/src/events/*.c) \
         $(wildcard $(LOCAL_PATH)/src/file/*.c) \
         $(wildcard $(LOCAL_PATH)/src/haptic/*.c) \
         $(wildcard $(LOCAL_PATH)/src/haptic/dummy/*.c) \
         $(wildcard $(LOCAL_PATH)/src/joystick/*.c) \
         $(wildcard $(LOCAL_PATH)/src/joystick/android/*.c) \
         $(wildcard $(LOCAL_PATH)/src/loadso/dlopen/*.c) \
         $(wildcard $(LOCAL_PATH)/src/power/*.c) \
         $(wildcard $(LOCAL_PATH)/src/power/android/*.c) \
         $(wildcard $(LOCAL_PATH)/src/render/*.c) \
         $(wildcard $(LOCAL_PATH)/src/render/*/*.c) \
         $(wildcard $(LOCAL_PATH)/src/stdlib/*.c) \
         $(wildcard $(LOCAL_PATH)/src/thread/*.c) \
         $(wildcard $(LOCAL_PATH)/src/thread/pthread/*.c) \
         $(wildcard $(LOCAL_PATH)/src/timer/*.c) \
         $(wildcard $(LOCAL_PATH)/src/timer/unix/*.c) \
         $(wildcard $(LOCAL_PATH)/src/video/*.c) \
         $(wildcard $(LOCAL_PATH)/src/video/android/*.c))
 
  
 　　LOCAL_CFLAGS += -DGL_GLEXT_PROTOTYPES
 LOCAL_LDLIBS := -ldl -lGLESv1_CM -lGLESv2 -llog
 
  
 　　include $(BUILD_SHARED_LIBRARY)
 
  
 　　三、如果直接编译的话会提示如下错误
 
  
 　　/home/SDL/jni/src/core/android/SDL_android.cpp:30:21: fatal error: EGL/egl.h: No such file or directory
 
  
 　　查看EGL的支持是在2.3版本以上，所以我们需要添加平台的支持，所以需要在jni目录下面创建一个Application.mk文件来指定编译平台，内容如下:
 
  
 　　APP_ABI := armeabi
 APP_PLATFORM := android-9
 
  
 　　四、在jni目录终端下运行ndk-build，就会编译出libSDL2.so，编译过程如下:
 
  
 　　root@zhangjie:/home/SDL/jni# ndk-build
 Compile arm    : SDL2 <= SDL_assert.c
 Compile arm    : SDL2 <= SDL.c
 Compile arm    : SDL2 <= SDL_error.c
 Compile arm    : SDL2 <= SDL_fatal.c
 Compile arm    : SDL2 <= SDL_hints.c
 Compile arm    : SDL2 <= SDL_log.c
 Compile arm    : SDL2 <= SDL_audio.c
 Compile arm    : SDL2 <= SDL_audiocvt.c
 Compile arm    : SDL2 <= SDL_audiodev.c
 Compile arm    : SDL2 <= SDL_audiotypecvt.c
 Compile arm    : SDL2 <= SDL_mixer.c
 Compile arm    : SDL2 <= SDL_wave.c
 Compile arm    : SDL2 <= SDL_androidaudio.c
 Compile arm    : SDL2 <= SDL_dummyaudio.c
 Compile arm    : SDL2 <= SDL_atomic.c
 Compile arm    : SDL2 <= SDL_spinlock.c
 Compile++ arm    : SDL2 <= SDL_android.cpp
 Compile arm    : SDL2 <= SDL_cpuinfo.c
 Compile arm    : SDL2 <= SDL_clipboardevents.c
 Compile arm    : SDL2 <= SDL_dropevents.c
 Compile arm    : SDL2 <= SDL_events.c
 Compile arm    : SDL2 <= SDL_gesture.c
 Compile arm    : SDL2 <= SDL_keyboard.c
 Compile arm    : SDL2 <= SDL_mouse.c
 Compile arm    : SDL2 <= SDL_quit.c
 Compile arm    : SDL2 <= SDL_touch.c
 Compile arm    : SDL2 <= SDL_windowevents.c
 Compile arm    : SDL2 <= SDL_rwops.c
 Compile arm    : SDL2 <= SDL_haptic.c
 Compile arm    : SDL2 <= SDL_syshaptic.c
 Compile arm    : SDL2 <= SDL_gamecontroller.c
 Compile arm    : SDL2 <= SDL_joystick.c
 Compile arm    : SDL2 <= SDL_sysjoystick.c
 Compile arm    : SDL2 <= SDL_sysloadso.c
 Compile arm    : SDL2 <= SDL_power.c
 Compile arm    : SDL2 <= SDL_syspower.c
 Compile arm    : SDL2 <= SDL_render.c
 Compile arm    : SDL2 <= SDL_yuv_mmx.c
 Compile arm    : SDL2 <= SDL_yuv_sw.c
 Compile arm    : SDL2 <= SDL_render_d3d.c
 Compile arm    : SDL2 <= SDL_render_gles2.c
 Compile arm    : SDL2 <= SDL_shaders_gles2.c
 Compile arm    : SDL2 <= SDL_render_gles.c
 Compile arm    : SDL2 <= SDL_render_gl.c
 Compile arm    : SDL2 <= SDL_shaders_gl.c
 Compile arm    : SDL2 <= SDL_render_psp.c
 Compile arm    : SDL2 <= SDL_blendfillrect.c
 Compile arm    : SDL2 <= SDL_blendline.c
 Compile arm    : SDL2 <= SDL_blendpoint.c
 Compile arm    : SDL2 <= SDL_drawline.c
 Compile arm    : SDL2 <= SDL_drawpoint.c
 Compile arm    : SDL2 <= SDL_render_sw.c
 Compile arm    : SDL2 <= SDL_rotate.c
 Compile arm    : SDL2 <= SDL_getenv.c
 Compile arm    : SDL2 <= SDL_iconv.c
 Compile arm    : SDL2 <= SDL_malloc.c
 Compile arm    : SDL2 <= SDL_qsort.c
 Compile arm    : SDL2 <= SDL_stdlib.c
 Compile arm    : SDL2 <= SDL_string.c
 Compile arm    : SDL2 <= SDL_thread.c
 Compile arm    : SDL2 <= SDL_syscond.c
 Compile arm    : SDL2 <= SDL_sysmutex.c
 Compile arm    : SDL2 <= SDL_syssem.c
 Compile arm    : SDL2 <= SDL_systhread.c
 Compile arm    : SDL2 <= SDL_timer.c
 Compile arm    : SDL2 <= SDL_systimer.c
 Compile arm    : SDL2 <= SDL_blit_0.c
 Compile arm    : SDL2 <= SDL_blit_1.c
 Compile arm    : SDL2 <= SDL_blit_A.c
 Compile arm    : SDL2 <= SDL_blit_auto.c
 Compile arm    : SDL2 <= SDL_blit.c
 Compile arm    : SDL2 <= SDL_blit_copy.c
 Compile arm    : SDL2 <= SDL_blit_N.c
 Compile arm    : SDL2 <= SDL_blit_slow.c
 Compile arm    : SDL2 <= SDL_bmp.c
 Compile arm    : SDL2 <= SDL_clipboard.c
 Compile arm    : SDL2 <= SDL_fillrect.c
 Compile arm    : SDL2 <= SDL_pixels.c
 Compile arm    : SDL2 <= SDL_rect.c
 Compile arm    : SDL2 <= SDL_RLEaccel.c
 Compile arm    : SDL2 <= SDL_shape.c
 Compile arm    : SDL2 <= SDL_stretch.c
 Compile arm    : SDL2 <= SDL_surface.c
 Compile arm    : SDL2 <= SDL_video.c
 Compile arm    : SDL2 <= SDL_androidclipboard.c
 Compile arm    : SDL2 <= SDL_androidevents.c
 Compile arm    : SDL2 <= SDL_androidgl.c
 Compile arm    : SDL2 <= SDL_androidkeyboard.c
 Compile arm    : SDL2 <= SDL_androidtouch.c
 Compile arm    : SDL2 <= SDL_androidvideo.c
 Compile arm    : SDL2 <= SDL_androidwindow.c
 StaticLibrary  : libstdc++.a
 SharedLibrary  : libSDL2.so
 Install        : libSDL2.so => libs/armeabi/libSDL2.so
 
  
 　　编译出sdl库后，我们就可以调用它的相关函数来实现我们的功能了