CODEWITHSUNDEEP
androidcallbackjava-native-interface
user2642459
user2642459

Reputation: 507

GetMethodID failes on android jni

I'm trying to implement a callback function in JNI/NDK. I got error in GetMethodID function

I want to execute a function in Java (from C) that has the following signature:

[java code]

public int callback(String msg) {
    cb_tv.setText(msg);
    return 1;
}

[native C code]

JNIEXPORT void JNICALL Java_com_example_hellojni1_nativeJava_testDirectCallback(JNIEnv *env, jclass obj) {
    static jmethodID cb = NULL;
    jclass cls = (*env)->GetObjectClass(env, obj);

    if(cb == NULL)  {
        cb = (*env)->GetMethodID(env, cls, "callback", "(Ljava/lang/String;)I");
    if(cb == NULL) return;
    }
    (*env)->CallVoidMethod(env, obj, cb, (*env)->NewStringUTF(env, "[C->J] callback"));

    return;
}

I get the following error:

08-01 16:26:43.617: W/dalvikvm(516): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
08-01 16:26:43.637: E/AndroidRuntime(516): FATAL EXCEPTION: main
08-01 16:26:43.637: E/AndroidRuntime(516): java.lang.NoSuchMethodError: callback

I don't understand the error. Is there anyone who can help me? Thank you in advance

Upvotes: 1

Views: 2861

Answers (1)

oliw
oliw

Reputation: 78

Like fadden metioned...

Check that your Java_com_example_hellojni1_nativeJava_testDirectCallback is declared "native" and not "static native".

This was my problem.

Upvotes: 4

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