android中使用jni，ndk的C语言回调方法

   不说太罗嗦了，回调分为Java代码和C语言代码两部分，我举的例子简单而且是通过调试可以运行的.

   Java代码：

   //====================================================================    packagecom.example.hellojni;

    importandroid.app.Activity;

importandroid.util.Log;

importandroid.widget.TextView;

    importandroid.os.Bundle;

publicclassHelloJniextendsActivity

{

publicStringmJniMsg;

publicHelloJni(){}

@Override

publicvoidonCreate(BundlesavedInstanceState)

{

            super.onCreate(savedInstanceState);

            //System.loadLibrary("hello-jni");

TextViewtv=newTextView(this);

tv.setText("Eagle,morning!");

setContentView(tv);

doCLanguageWork();

       }

       public void myCallbackFunc(String nMsg)

{

Log.v("EagleTag","backmessage:"+nMsg);

}

        publicnative String doCLanguageWork();

       static

       {

System.loadLibrary("hello-jni");

}

    }

   C语言代码部分：

   //====================================================================

#include<string.h>

    #include<jni.h>

    JNIEXPORTjstring JNICALL

jobjectgJniObj;

jclassgJniClass;

   jmethodID gJinMethod;

voidGetInstance(JNIEnv*env,jclassobj_class);

    void DisplayCallBack(JNIEnv* env);

    JNIEXPORTjstring JNICALL

Java_com_example_hellojni_HelloJni_doCLanguageWork(JNIEnv*env,jobjectobj)

{

chartChar[256];

gJniClass=0;

gJinMethod=0;

gJniClass=(*env)->FindClass(env,"com/example/hellojni/HelloJni");

if(gJniClass==0||gJniClass==NULL)

return(*env)->NewStringUTF(env,"-1");

        GetInstance(env,gJniClass);

        gJinMethod=(*env)->GetMethodID(env,gJniClass,"myCallbackFunc","(Ljava/lang/String;)V");

if(gJinMethod==0||gJinMethod==NULL)

return(*env)->NewStringUTF(env,"-2");

strcpy(tChar,"PROG:10");

(*env)->CallVoidMethod(env,gJniObj,gJinMethod,(*env)->NewStringUTF(env,tChar));

DisplayCallBack(env);

return(*env)->NewStringUTF(env,"Eagleisreallygreat!......");

    }

    voidGetInstance(JNIEnv* env, jclass obj_class) 

{

jmethodIDconstruction_id=(*env)->GetMethodID(env,obj_class,"<init>","()V");

gJniObj=(*env)->NewObject(env,obj_class,construction_id);

   } 

    voidDisplayCallBack(JNIEnv* env)

{

chartChars[256];

strcpy(tChars,"DEBUG:Hello,Eagle");

(*env)->CallVoidMethod(env,gJniObj,gJinMethod,(*env)->NewStringUTF(env,tChars));

}

怎么样？不是很难吧？具体能不能理解，就看大家的编程经验怎么样了？