Android下引用系统库(.so文件)的方法及问题

1、我们看一下如何在Android环境下引用/system/lib下的.so文件（若您也对此有所了解，还望不吝赐教后面的问题，先谢为避免讲得混淆，先将我的代码的结构贴出来Andr&idJniT&st音5rc由,JAndrciellniTestActivity.j;TCaEIMative.javaaMfe&fegen.Litdt+L：-已二jAndroid2.2m砧eUbin匕二include-telephony国cit_cdma_sm&rh国ril.h&librilmoek-rilreferEnce-nl&riId.秒Andraid.mkl_cjma

2、rsccm-CallNativc.h国testx包Hbt日amneabipr；libtest,so&objfe®旦AndroidManifest.xmlQguwd.cfg凿project,propertiesThninflrnid-JImiTcrtH首先，新建Android工程：AndroidJniTest,在AndroidJniTestActivity.java中的代码如下:javaviewplaincopyprint?1. ;2. importandroid.app.Activity;3. importandroid.os.Bundle;4. publicclassAnd

3、roidJniTestActivityextendsActivity5. /*Calledwhentheactivityisfirstcreated.*/6. Override7. publicvoidonCreate(BundlesavedInstanceState)8. super.onCreate(savedInstanceState);9. setContentView(R.layout.main);10. System.loadLibrary("test");11. CallNativecallnative=newCallNative();12. bytecmd=

4、(byte)'u004c'13. inta=callnative.writeCmd(cmd,"/system/lib");14.15. 16. ;importandroid.app.Activity;importandroid.os.Bundle;publicclassAndroidJniTestActivityextendsActivity/*Calledwhentheactivityisfirstcreated.*/OverridepublicvoidonCreate(BundlesavedInstanceState)super.onCreate(sav

5、edInstanceState);setContentView(R.layout.main);System.loadLibrary("test");CallNativecallnative=newCallNative();bytecmd=(byte)'u004c'inta=callnative.writeCmd(cmd,"/system/lib");再在包下建立文件：CallNative.java代码：javaviewplaincopyprint?1. ;2. publicclassCallNative3. publicnativebyt

6、ereadCmd(Stringpath);4. publicnativeintwriteCmd(bytecmd,Stringpath);5. ;publicclassCallNativepublicnativebytereadCmd(Stringpath);publicnativeintwriteCmd(bytecmd,Stringpath);利用javah工具创建本地库文件的头文件mars_com_CallNative.h代码：cppviewplaincopyprint?1. /*DONOTEDITTHISFILE-itismachinegenerated*/2. #include<j

7、ni.h>3. /*Headerforclassmars_com_CallNative*/4. #ifndef_Included_mars_com_CallNative5. #define_Included_mars_com_CallNative6. #ifdef_cplusplus7. extern"C"8. #endif9. /*10. *Class:mars_com_CallNative11. *Method:readCmd12. *Signature:(Ljava/lang/String;)B13. */14. JNIEXPORTjbyteArrayJNICA

8、LLJava_mars_com_CallNative_readCmd15. (JNIEnv*,jobject,jstring);16. /*17. *Class:mars_com_CallNative18. *Method:writeCmd19. *Signature:(BLjava/lang/String;)I20. */21. JNIEXPORTjintJNICALLJava_mars_com_CallNative_writeCmd22. (JNIEnv*,jobject,jbyteArray,jstring);23. #ifdef_cplusplus24. 25. #endif26. #

9、endif/*DONOTEDITTHISFILE-itismachinegenerated*/#include<jni.h>/*Headerforclassmars_com_CallNative*/#ifndef_Included_mars_com_CallNative#define_Included_mars_com_CallNative#ifdef_cplusplusextern"C"#endif/*Class:mars_com_CallNative*Method:readCmd*Signature:(Ljava/lang/String;)B*/JNIEXP

10、ORTjbyteArrayJNICALLJava_mars_com_CallNative_readCmd(JNIEnv*,jobject,jstring);/*Class:mars_com_CallNative*Method:writeCmd*Signature:(BLjava/lang/String;)I*/JNIEXPORTjintJNICALLJava_mars_com_CallNative_writeCmd(JNIEnv*,jobject,jbyteArray,jstring);#ifdef_cplusplus#endif#endifcppviewplaincopyprint?1.&l

11、t;pre><pre>javaviewplaincopyprint?1.<preclass="cpp"name="code"><pre><preclass="cpp"name="code"><pre>至于如何生成此头文件，可自行学习，这里不多讲了第二,在工程目录下建立文件夹：jni,将文件mars_com_CallNative.h拷贝到此目录下，再在此目录下建立文件test.c代码：#include"mars_com_CallNative.

12、h"#include<jni.h>#include<stdio.h>#include<string.h>#include<assert.h>#include<android/log.h>#include<dlfcn.h>#include<unistd.h>#include<sys/types.h>#include"include/telephony/ril.h"#defineLOGD()_android_log_print(ANDROID_LOG_DEBUG,"

13、;keymatch",_VA_ARGS_)JNIEXPORTjbyteArrayJNICALLJava_mars_com_CallNative_readCmd(JNIEnv*evn,jobjectobj,jstringjstr)exit(0);JNIEXPORTjintJNICALLJava_mars_com_CallNative_writeCmd(JNIEnv*evn,jobjectjobj,jbyteArrayjba,jstringjstr)return56;jintJNI_OnLoad(JavaVM*vm,void*reserved)LOGD("JNIONLOADsu

14、ccess!");char*path="/system/lib/libril.so"void*filehandle0=dlopen(path,RTLD_LAZY|RTLD_GLOBAL);/引用path指向的库：/system/lib/libril.sochar*ll;intpid;if(filehandle0)LOGD("opensosuccess!");char*(*requesttostring)(int);if(0=pid)sleep(1);/子进程睡眠一秒requesttostring=(char*(*)(int)dlsym(file

15、handle0,"requestToString");pid=fork();if(requesttostring)LOGD("callfunctionrequesttostringOK!");ll=requesttostring(RIL_REQUEST_GET_NEIGHBORING_CELL_IDS);RIL_REQUEST_GET_NEIGHBORING_CELL_IDS定义在include/telephony/ril.h中LOGD("thevalueofrequesttostringis%s",*ll);elseLOGD(&qu

16、ot;callfunctiongetinformation!ERROR!");LOGD("ok");elseif(0<pid)LOGD("intheparent%s'n",getpid();elseLOGD("forkerror");将Android源码hardware/ril下的include文件夹也拷贝到jni文件夹下(因为在requesttostring(RIL_REQUEST_GET_NEIGHBORING_CELL_IDS)中使用的RIL_REQUEST_GET_NEIGHBORING_CELL_ID

17、S在include文件夹下的ril.h中定义了)在jni文件夹下新建Android.mk文件，内容如下：plainviewplaincopyprint?1. LOCAL_PATH:=$(callmy-dir)2. include$(CLEAR_VARS)3. LOCAL_MODULE:=test4. LOCAL_SRC_FILES:=test.c5. LOCAL_LDLIBS:=-llog6. LOCAL_CERTIFICATE:=platform7. include$(BUILD_SHARED_LIBRARY)LOCAL_PATH:=$(callmy-dir)include$(CLEAR_V

18、ARS)LOCAL_MODULE:=testLOCAL_SRC_FILES:=test.cLOCAL_LDLIBS:=-llogLOCAL_CERTIFICATE:=platforminclude$(BUILD_SHARED_LIBRARY)第三，接下来就是编译的时候了。在cygwin下$ndk/ndk-build卅$ndk/nd!tJbuildGompllatliumb=test<=testSJiaredLibrarji；lil)tcst,soInstall:lihtestiso=>libe/apmeahi/libtest.so显示编译通过了，F5刷新工程，发现在工程目录下多了一

19、下文件夹：libs,其中就包含了生成的文件:libtest.so最后，运行。发现在Logcat下有这些信息：Trnep©AppJisyrtipnT叼"dt33<335:33:4；,f-OL皿士二:业ktITEBUTE:&tLKh:fthreadT5ioderThreadI31failedM-1325d3:4*.337郎cfara.30£dalvifcT：tiding1cj.lLit-daa-da-a,iran,zge/life,libtez*j3£«IjiH'fei£SSzQ3-1?05:31:4.337439M

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25、E：fRL刑util*1X&WXE!：J<：0£I03r13g§；06；5£JQ?寸斜Fna4/"*白事：iiTPTni:邛：OH%Ol：«iwjrCt附如电州,驰上，.ummMJSLirnftttl1!7JUSN址1果”3(IMS>0空凡涯出CLHT3Irfi：-r«dN7也芳，口：1MX匕七弟itE?喈：OJ-1:g匚跖图馨fy:；Esjr：K!j女工豺匚能"：*上"：1门；JT%湍：，"；1式汉3丹：小；七:注：？酢：4G：；H=7好了，问题来了。问题一、从绿色部分的内容来看，应该是成功引用了/system/lib/libril.so的，但为什么在上面只输出了TimePIDApplicctiGnTag7erf：C0-13053:15.477UU7E：a?aAat£"