Opening browser from C++

[Muzza]

Hi,

I need an event in my C++ code to start the web browser.
I have java function in my Activity class to do this:

private void OpenURL( String url )
{
Uri uriUrl = Uri.parse( url );
Intent intent = new Intent(Intent.ACTION_VIEW, uriUrl);
intent.setFlags( Intent.FLAG_ACTIVITY_NEW_TASK );
startActivity( intent );
}

And am calling it from C++ like this:

gJavaVM->AttachCurrentThread( &gAndroidActivityEnv, NULL );
jstring jstr = gAndroidActivityEnv->NewStringUTF("www.google.com");
jclass clazz = gAndroidActivityEnv->FindClass("com/
MyAndroidActivity");
jmethodID openURLFunction = gAndroidActivityEnv->GetMethodID(clazz,
"OpenURL", "(Ljava/lang/String;)V");
gAndroidActivityEnv->CallVoidMethod( gAndroidActivityThis,
openURLFunction, jstr );
gJavaVM->DetachCurrentThread();

The result is an immediate fault crash with just some system dump data
as output.
It gets in to OpenURL ok, and if I just replace it with some debug
output there is no problem. It's just the call to startActivity that
seems to be the problem.
OpenURL works fine when called from the Activity in Java.

I thought it was perhaps a thread issue, so I tried the
AttachCurrentThread, but clearly it doesn't do what I hoped it would.

Can anyone offer any suggestions please?
Thanks

[Alexander Fradiani]

Hi, i think you're calling an instance method, but the JNI call is not
using the Java object to be used when calling the function.

I open a browser from my c++ like this:

void jni_openURL(const char* url) {
//LLamar a funcion desde la instancia hungrypigs.
jclass appClass = mEnv->GetObjectClass(appClassObj);
jmethodID mid = mEnv->GetMethodID(appClass, "openURL",
"(Ljava/lang/String;)V");
mEnv->CallVoidMethod(appClassObj, mid, mEnv->NewStringUTF(url));
//llamar a la funcion
}

But you need to have appClassObj initiated, i do that calling a method
named nativeInstanceInit from Java:

void package_class_nativeInstanceInit(JNIEnv* env, jobject thiz) {
appClassObj = env->NewGlobalRef(thiz);
}

I used this guide:
http://journals.ecs.soton.ac.uk/java/tutorial/native1.1/implementing/index.html

Hope that can help.

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[l.b.]

 Hi. to start a browser, I think it's easier to use "am" comannd.

 char* args = {"/system/bin/am", "start","-a", "android.intent.action.VIEW", "http://www.google.com/"};

 if(fork() == 0) {

     execvp("/system/bin/am", args);

 }

 

 Sincerely,

[Dianne Hackborn]

No.  No no no no.  Do you see "am" documented anywhere in the SDK or NDK?  No.  This is not an API.

Use JNI.

And besides using JNI this is going to be like 100x faster to run.  Launching the am command requires starting a clean Dalvik instance in its own process (not forked from zygote) and it takes a *noticeable* amount of time for that to launch.

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[Alastair Murray]

Thanks for the info, I'm still having problems though.

For some reason, using your code GetMethodID is returning NULL for me.

In my code GetMethodID was valid, but calling it resulted in a crash.

Could you give me some more details about the java side please?

Are you call a function in your Activity or somewhere else?

I'm copying the Activity env and class pointer, but then the call from c++ to java occurs

later, via a call to GLSurfaceView Render (this is the only 'link' in my game where java does a c++ call every frame)

I suspect that it's not working for me as I believe GLSurfaceView runs on a different thread.

I've tried adding the openURL function in to the surface view class too (and copying the env and pointer from there), but still no luck.

Thanks