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

1 public class  MediaInfo2 {3     public int nWidth;4     public int nHeight;5     public String strStream;6 }

java jni接口定义

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

c++ ndk 实现代码

 1 JNIEXPORT jint JNICALL Java_src_jni_RtspConnect_GetMediaInfo 2   (JNIEnv *e, jclass c, jint h, jobject o) 3 { 4     //获取Java中的实例类  5     jclass objectClass = (e)->FindClass("src/jni/MediaInfo");  6   7     //获取类中每一个变量的定义  8     jfieldID strStream = (e)->GetFieldID(objectClass, "strStream", "Ljava/lang/String;");  9     jfieldID nHeight = (e)->GetFieldID(objectClass, "nHeight", "I"); 10     jfieldID nWidth =  (e)->GetFieldID(objectClass, "nWidth", "I");11  12  13     //给每一个实例的变量付值 14     (e)->SetIntField(o, nHeight, 10); 15     (e)->SetIntField(o, nWidth, 100);16     (e)->SetObjectField(o, strStream, (e)->NewStringUTF("my stream"));  17     18     return 0; 19 }

Java 调用

1  MediaInfo info = new MediaInfo();2         RtspConnect.GetMediaInfo(0, info);3         Log.i("info", ""+info.nHeight);4         Log.i("info", ""+info.nWidth);5         Log.i("info", ""+info.strStream);

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