比如 有个库A.so 想使用另外一个库B.so里的函数,调用B.so中的get_value()函数获取该库中的变量值。
B.so里的这个变量值是上层通过JNI控制的,是变化的
可是我在A.so里把从B.so里获取的值打出来 一直是一个不变的值。
请帮忙看看。谢谢
------解决方案--------------------
以下是两个.c的调用。
TwoLibs.java
public class TwoLibs extends Activity{
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
TextView tv = new TextView(this);
int x = 1000;
int y = 42;
System.loadLibrary("twolib-second");
int z = add(x, y);
tv.setText( "The sum of " + x + " and " + y + " is " + z );
setContentView(tv);
}
public native int add(int x, int y);
}
jni文件夹下面的文件:
Android.mk
LOCAL_PATH:= $(call my-dir)
# first lib, which will be built statically
#
include $(CLEAR_VARS)
LOCAL_MODULE := libtwolib-first
LOCAL_SRC_FILES := first.c
include $(BUILD_STATIC_LIBRARY)
# second lib, which will depend on and include the first one
#
include $(CLEAR_VARS)
LOCAL_MODULE := libtwolib-second
LOCAL_SRC_FILES := second.c
LOCAL_STATIC_LIBRARIES := libtwolib-first
include $(BUILD_SHARED_LIBRARY)
first.c
#include "first.h"
int first(int x, int y)
{
return x + y;
}
first.h
#include "first.h"
#include <jni.h>
jint
Java_com_example_twolibs_TwoLibs_add( JNIEnv* env,
jobject this,
jint x,
jint y )
{
return first(x, y);
}
second.c
#include "first.h"
#include <jni.h>
jint
Java_com_example_twolibs_TwoLibs_add( JNIEnv* env,
jobject this,
jint x,
jint y )
{
return first(x, y);
}
最后你自己去把用NDK编译下工程。然后在执行就OK了。其实这些都可以再ndk\android-ndk-r7b\samples里面找到。