文章目录
代码下载:http://dl.dbank.com/c0c0xs3b24
一、JNI实现回调
通过JNI在Native层调用JAVA层的方法,来实现Native层向JAVA层传递消息。
JNICallback.java
public class JNICallback extends Activity {
static {
System.loadLibrary("callback");
}
public void callback(int notify_id, int param)
{
Log.e("JNICallback","notify_id="+notify_id+";param="+param);
}
public native void setCallBack();
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setCallBack();
}
}
com_JNICallback_JNICallback.cpp
void JNICALL Java_com_JNICallback_JNICallback_setCallBack (JNIEnv *env, jobject obj) { LOGE("jni callback (0)"); jclass cls = env->GetObjectClass(obj); jmethodID callback = env->GetMethodID(cls,"callback","(II)V"); env->CallVoidMethod(obj,callback,5,10); LOGE("jni callback (1)"); }
javah -classpath . -jni com.JNICallback.JNICallback(包名+类名)
二、JNI调用JAVA函数
获取实例的类定义 jclass cls = env->GetObjectClass(obj);
获取方法定义 jmethodID callback = env->GetMethodID(cls,"callback","(II)V");
调用方法 env->CallVoidMethod(obj,callback,5,10);
三、参数和返回值的格式
参考 http://java.sun.com/docs/books/jni/html/jniTOC.html