[android-developers] Re: Android JNI
Hi,all:
I think JNI is supported in 0.9 Beta. Because I wrote a
helloworld's jni application in 0.9 beta,and it seem running
successfully.
but i encounter a trouble, I can not do any writing operation,
like remove/rename file.
Next is JNI C code:
JNIEXPORT void JNICALL Java_jprint_print(JNIEnv *env, jobject obj)
{
remove(/data/a.log);
rename(/data/b.log, /data/c.log);
printf(hello jni===\r\n);
}
JNIEXPORT jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
JNIEnv *env;
JNINativeMethod meth;
jclass k;
jint r;
r = (*vm)-GetEnv (vm, (void **) env, JNI_VERSION_1_4);
k = (*env)-FindClass (env, com.android.helloactivity.jprint);
meth.name = print;
meth.signature = ()V;
meth.fnPtr = Java_jprint_print;
r = (*env)-RegisterNatives (env, k, meth, 1);
return JNI_VERSION_1_4;
}
JNIEXPORT void JNI_OnUnload(JavaVM *vm, void *reserved)
{
JNIEnv *env;
jclass k;
jint r;
r = (*vm)-GetEnv (vm, (void **) env, JNI_VERSION_1_2);
k = (*env)-FindClass (env, com.android.helloactivity.jprint);
(*env)-UnregisterNatives(env, k);
}
It is very important to call RegisterNatives() to register native
interface. It will show error information Not Implemention if you
do not register it.
Next is Jave Code:
public class jprint
{
public native void print();
static
{
try {
Log.i(JNI, Trying to load jni .so);
System.out.println(System.getProperty(java.library.path));
System.load(/data/libjnilibs.so);
}
catch (UnsatisfiedLinkError ule) {
Log.e(JNI, ule.getMessage());
}
}
}
Add code to Android OnCreate():
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
jprint p = new jprint();
p.print();
...
}
It is also very important to call System.load(/data/libjnilibs.so)
in java instead of System.loadLibrary(), because System.loadLibrary()
always load library from /system/lib directory.
because /system/bin is readonly file system. so you can push .so file
to /data.
1.build out .so file using arm-eabi compiler
2.push .so to /data directoy: adb push d:/libjnilibs.so /data.(I use
windows's emulator and tool)
3.run java application, you will see(via adb logcat):
I/JNI ( 524): Trying to load jni .so
I/System.out( 524): /system/lib
D/dalvikvm( 524): Trying to load lib /data/libjnilibs.so 0x433f22d0
D/dalvikvm( 524): Added shared lib /data/libjnilibs.so 0x433f22d0
I/ActivityManager( 50): Displayed activity com.android.helloactivity
No, the native interface print() will be called from Jave application.
But It can not remove file in JNI. I think it is limited by java's
security management.
JNIEXPORT void JNICALL Java_jprint_print(JNIEnv *env, jobject obj)
{
remove(/data/a.log);
rename(/data/b.log, /data/c.log);
printf(hello jni===\r\n);
}
I do not know how to solve this problem. who can tell me and
suggestion?
On Aug 26, 5:01 am, hackbod [EMAIL PROTECTED] wrote:
Native code is not supported in 1.0.
On Aug 25, 11:15 am, Tyler Ernst [EMAIL PROTECTED] wrote:
Thanks, that was exactly what we needed. We realize JNI is not
supported, but Java code is just too slow to do the things we need...
On Aug 25, 2:23 am, Volker Gropp [EMAIL PROTECTED] wrote:
On Aug 22, 9:30 pm, Tyler Ernst [EMAIL PROTECTED] wrote:
Also since the 0.9 beta has been released I have been unable to copy
the .so to the /system/lib directory of the emulator. If anyone has
found a way to do this that would be greatly appreciated.
Hi,
you have to mount the system rw. To do so run `adb remount` before you
push your .so. And keep in mindJNIwill not be supported, or did you
find a way to deploy your native lib with a .apk?
Volker Gropp- Hide quoted text -
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http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html
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[android-developers] Re: Android JNI
On Aug 25, 8:36 pm, ccf2000 [EMAIL PROTECTED] wrote: I think JNI is supported in 0.9 Beta. Because I wrote a helloworld's jni application in 0.9 beta,and it seem running successfully. Native code is NOT SUPPORTED in 1.0. Anything you do here is a hack, which will not be supported across any particular builds of the platform, will run into any number of arbitrary bugs or limitations that may be different across each release of the platform, etc. Feel free to hack away at this stuff if you want, but you have to understand that these are not things a normal application can do, and anything you do here will probably result in your application breaking in future releases (possibly every release) of the platform. As such, all of the discussion about this should be moved to the android- internals group. As far as writing files, applications are not allowed to write outside of their dedicated data directories, as described here: http://code.google.com/android/devel/security.html --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Android JNI
On Aug 22, 9:30 pm, Tyler Ernst [EMAIL PROTECTED] wrote: Also since the 0.9 beta has been released I have been unable to copy the .so to the /system/lib directory of the emulator. If anyone has found a way to do this that would be greatly appreciated. Hi, you have to mount the system rw. To do so run `adb remount` before you push your .so. And keep in mind JNI will not be supported, or did you find a way to deploy your native lib with a .apk? Volker Gropp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Android JNI
Thanks, that was exactly what we needed. We realize JNI is not supported, but Java code is just too slow to do the things we need... On Aug 25, 2:23 am, Volker Gropp [EMAIL PROTECTED] wrote: On Aug 22, 9:30 pm, Tyler Ernst [EMAIL PROTECTED] wrote: Also since the 0.9 beta has been released I have been unable to copy the .so to the /system/lib directory of the emulator. If anyone has found a way to do this that would be greatly appreciated. Hi, you have to mount the system rw. To do so run `adb remount` before you push your .so. And keep in mindJNIwill not be supported, or did you find a way to deploy your native lib with a .apk? Volker Gropp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Android JNI
Blame the Dalvik, not java :P On Mon, Aug 25, 2008 at 2:15 PM, Tyler Ernst [EMAIL PROTECTED] wrote: Thanks, that was exactly what we needed. We realize JNI is not supported, but Java code is just too slow to do the things we need... On Aug 25, 2:23 am, Volker Gropp [EMAIL PROTECTED] wrote: On Aug 22, 9:30 pm, Tyler Ernst [EMAIL PROTECTED] wrote: Also since the 0.9 beta has been released I have been unable to copy the .so to the /system/lib directory of the emulator. If anyone has found a way to do this that would be greatly appreciated. Hi, you have to mount the system rw. To do so run `adb remount` before you push your .so. And keep in mindJNIwill not be supported, or did you find a way to deploy your native lib with a .apk? Volker Gropp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Android JNI
Native code is not supported in 1.0. On Aug 25, 11:15 am, Tyler Ernst [EMAIL PROTECTED] wrote: Thanks, that was exactly what we needed. We realize JNI is not supported, but Java code is just too slow to do the things we need... On Aug 25, 2:23 am, Volker Gropp [EMAIL PROTECTED] wrote: On Aug 22, 9:30 pm, Tyler Ernst [EMAIL PROTECTED] wrote: Also since the 0.9 beta has been released I have been unable to copy the .so to the /system/lib directory of the emulator. If anyone has found a way to do this that would be greatly appreciated. Hi, you have to mount the system rw. To do so run `adb remount` before you push your .so. And keep in mindJNIwill not be supported, or did you find a way to deploy your native lib with a .apk? Volker Gropp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Android JNI
Actually, the errors stemmed from some compile-related incompatabilities. Is it possible to do this from win32, or do I have to do it from Linux? On Aug 22, 11:36 am, vol [EMAIL PROTECTED] wrote: I'm having trouble building the JNI example athttp://davanum.wordpress.com/2007/12/09/android-invoke-jni-based-meth... . First up, is it possible to actually do this from windows? Do I have to do this in a linux environment? I would think that doing this from windows is possible, but I don't have jdk/include/linux, just jdk/ include/win32, so that's throwing me. Second, I am at step 6, and am attempting to use arm-none-linux- gnueabi-gcc. $ arm-none-linux-gnueabi-gcc -I/cygdrive/c/Program\ Files/Java/ jdk1.6.0_04/include/ -I/cygdrive/c/Program\ Files/Java/jdk1.6.0_04/ include/win32/ -fpic -c org_apache_NativeAdd.c In file included from org_apache_NativeAdd.c:1: org_apache_NativeAdd.h:2:17: error: jni.h: No such file or directory In file included from org_apache_NativeAdd.c:1: org_apache_NativeAdd.h:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'jlong' org_apache_NativeAdd.c:3: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'jlong' Ok. Cygwin + arm-none-linux-gnueabi-gcc didn't want to seem to include anything like that, so I just flat out copied over the contents, and it was happy to include them. Unfortunately, it didn't want to build them, giving me other errors like those seen above. What do I have set up incorrectly for building JNI? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
[android-developers] Re: Android JNI
You are getting those errors because you are building for linux, but using the windows jni includes. This is because the compiler does not recognize the __int64 microsoft extension. You can build this in a windows environment, but you'll have to get the include files from the linux environment. Also since the 0.9 beta has been released I have been unable to copy the .so to the /system/lib directory of the emulator. If anyone has found a way to do this that would be greatly appreciated. Thanks On Aug 22, 10:46 am, vol [EMAIL PROTECTED] wrote: Actually, the errors stemmed from some compile-related incompatabilities. Is it possible to do this from win32, or do I have to do it from Linux? On Aug 22, 11:36 am, vol [EMAIL PROTECTED] wrote: I'm having trouble building the JNI example athttp://davanum.wordpress.com/2007/12/09/android-invoke-jni-based-meth... . First up, is it possible to actually do this from windows? Do I have to do this in a linux environment? I would think that doing this from windows is possible, but I don't have jdk/include/linux, just jdk/ include/win32, so that's throwing me. Second, I am at step 6, and am attempting to use arm-none-linux- gnueabi-gcc. $ arm-none-linux-gnueabi-gcc -I/cygdrive/c/Program\ Files/Java/ jdk1.6.0_04/include/ -I/cygdrive/c/Program\ Files/Java/jdk1.6.0_04/ include/win32/ -fpic -c org_apache_NativeAdd.c In file included from org_apache_NativeAdd.c:1: org_apache_NativeAdd.h:2:17: error: jni.h: No such file or directory In file included from org_apache_NativeAdd.c:1: org_apache_NativeAdd.h:15: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'jlong' org_apache_NativeAdd.c:3: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'jlong' Ok. Cygwin + arm-none-linux-gnueabi-gcc didn't want to seem to include anything like that, so I just flat out copied over the contents, and it was happy to include them. Unfortunately, it didn't want to build them, giving me other errors like those seen above. What do I have set up incorrectly for building JNI?- Hide quoted text - - Show quoted text - --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Android Developers group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] Announcing the new Android 0.9 SDK beta! http://android-developers.blogspot.com/2008/08/announcing-beta-release-of-android-sdk.html For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~--~~~~--~~--~--~---
