（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

1 public class  MediaInfo
2 {
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);

 

posted on 2014-10-30 15:28  darkknightzh  阅读(809)  评论(0)  编辑  收藏  举报

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