android中使用jni，ndk的C语言回调方法

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???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;

??? public classHelloJni extends Activity
??? {
????????public String mJniMsg;
?
????????public HelloJni(){}
????????@Override
????????publicvoid onCreate(Bundle savedInstanceState)
???????{
????????????super.onCreate(savedInstanceState);

????????????//System.loadLibrary("hello-jni");
????????????TextView? tv = new TextView(this);
????????????tv.setText("Eagle,morning!");
?????????????setContentView(tv);
????????????doCLanguageWork();
???????}

???????public void myCallbackFunc(String nMsg)
???????{
???????????Log.v("EagleTag","back message:"+nMsg);
???????}
????????publicnative String doCLanguageWork();

???????static

???????{
???????????System.loadLibrary("hello-jni");
???????}
??? }

?

???C语言代码部分：

???//====================================================================
??? #include<string.h>
????#include<jni.h>

??? JNIEXPORTjstring JNICALL
???jobject??gJniObj;
???jclass??gJniClass;
???jmethodID?gJinMethod;

??? void?GetInstance(JNIEnv* env, jclass obj_class);
??? void?DisplayCallBack(JNIEnv* env);

??? JNIEXPORTjstring JNICALL
???Java_com_example_hellojni_HelloJni_doCLanguageWork(JNIEnv* env,jobject obj)
??? {
????????char ?tChar[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, "Eagle is reallygreat!......");
??? }

??? 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)
??? {
????????char tChars[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？