NDK using dynamic library (shared library problem)

posts by Thomas082 edited 2012-03-20 23:47:15

(1) to generate dynamic library

Build a file folder named JNI, after which add two documents, namely add.c and Android.mk,
shown below
add.c

 # include  

int add (int a, int b) 
{
return a + b; 
} 

Android.mk

 LOCAL_PATH: = $ (call my-dir) 

include $ (CLEAR_VARS) 

LOCAL_MODULE: = add 
LOCAL_SRC_FILES: = add.c 

include $ (BUILD_SHARED_LIBRARY) 

After ndk-build, got libadd.so


(2) modify the hello-jni project

is as follows
hello-jni comes Lie, I tried to return the string before calling about the dynamic library add (int, int) method, the modified
hello-jni.c

 # include  
# Include  
# Include  
# Include  

jstring 
Java_com_example_hellojni_HelloJni_stringFromJNI (JNIEnv * env, 
jobject thiz) 
{
add (1, 2); 
return (* env) -> NewStringUTF (env, "Hello from JNI!"); 
} 

Android.mk

 LOCAL_PATH: = $ (call my-dir) 

include $ (CLEAR_VARS) 

LOCAL_MODULE: = add 
LOCAL_SRC_FILES: = libadd.so 
LOCAL_EXPORT_C_INCLUDES: = $ (LOCAL_PATH) / include 

include $ (PREBUILT_SHARED_LIBRARY) 

include $ (CLEAR_VARS) 

LOCAL_MODULE: = hello-jni 
LOCAL_SRC_FILES: = hello-jni.c 
LOCAL_SHARED_LIBRARIES: = add 

include $ (BUILD_SHARED_LIBRARY) 

Yes, I'm still include files add a simple add.h

 int add (int a, int b) 

Of course, I also added a JNI directory libadd.so

Finally, I would certainly use the NDK 7 compiled through, and \ hello-jni \ libs \ armeabi have two libraries libadd.so and libhello-jni.so
Library libadd.so, is automatically in the past, not the past
I manually copy copy
Originally feel that this should be no problem under the bar, but throw an error:
03-20 23:17:30.434: D / dalvikvm (192): Trying to load lib / data / data / com.example.hellojni / lib / libhello-jni.so 0x43757ca8
03-20 23:17:30.474: I / dalvikvm (192): Unable to dlopen (/ data / data / com.example.hellojni / lib / libhello-jni.so): Cannot load library: link_image [1638]: 30 could not load needed library 'libadd.so' for 'libhello-jni.so' (load_library [984]: Library 'libadd.so' not found) < br />

I do not understand why? We have encountered this problem? How to solve it?

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Reply:
LOCAL_SHARED_LIBRARIES: =-ladd plus-l
Reply:


LOCAL_SHARED_LIBRARIES: = add this right

Reply:
To add System.loadLibrary ("add");
Reply:
Later I ask is how to solve it? I also encountered the same problem, please enlighten me ~ Thank you
Reply:
Thomas082 answer right, to System.loadLibrary ("add");
Reply:
The landlord Hello, may I ask "
you mentioned in the articleYes, I'm still include files add a simple add.h "
This include file is where what is meant? ? ? ?