android ndk 给结构体赋值的方法

来源：互联网发布：移动4g网络模式选择编辑：程序博客网时间：2024/06/01 07:34

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, 10);

(e)->SetIntField(o, nWidth, 100);

(e)->SetObjectField(o, strStream, (e)->NewStringUTF("my stream"));

return 0;

}

Java 调用

MediaInfo info = new MediaInfo();

RtspConnect.GetMediaInfo(0, info);

Log.i("info", ""+info.nHeight);

Log.i("info", ""+info.nWidth);

Log.i("info", ""+info.strStream);

0 0