（转）android ndk 给结构体赋值的方法

转自：http://www.cnweblog.com/fly2700/archive/2012/03/21/320083.html

1，java 代码 结构体定义

 public class  MediaInfo
 {
     public int nWidth;
     public int nHeight;
     public String strStream;
 }

java jni接口定义

public native static int       GetMediaInfo(int handle, MediaInfo info); //

c++ ndk 实现代码

 JNIEXPORT jint JNICALL Java_src_jni_RtspConnect_GetMediaInfo
   (JNIEnv *e, jclass c, jint h, jobject o)
 {
     //获取Java中的实例类
     jclass objectClass = (e)->FindClass("src/jni/MediaInfo"); 

     //获取类中每一个变量的定义
     jfieldID strStream = (e)->GetFieldID(objectClass, "strStream", "Ljava/lang/String;");
     jfieldID nHeight = (e)->GetFieldID(objectClass, "nHeight", "I");
     jfieldID nWidth =  (e)->GetFieldID(objectClass, "nWidth", "I");

     //给每一个实例的变量付值
     (e)->SetIntField(o, nHeight, );
     (e)->SetIntField(o, nWidth, );
     (e)->SetObjectField(o, strStream, (e)->NewStringUTF("my stream"));  

     return ;
 }

Java 调用

  MediaInfo info = new MediaInfo();
         RtspConnect.GetMediaInfo(, info);
         Log.i("info", ""+info.nHeight);
         Log.i("info", ""+info.nWidth);
         Log.i("info", ""+info.strStream);