what is the possible reason of " Unable to initialize SurfaceComposerClient " ?

[workzj]

my jni code :

android::spandroid::SurfaceComposerClient sc = new android::SurfaceComposerClient();

is failed .

i don't know why ??
look up the android source , i wirte the test code like this :

//test code
sp<ISurfaceComposer> sm(ComposerService::getComposerService());
if (sm != 0) {
    sp<ISurfaceComposerClient> conn = sm->createConnection();
    if (conn != 0) {
        LOG("init success ... ");
        return 1;
    }
    LOG("conn == 0");
    return -1;
}

the run result is : conn == 0 .
my question is why createConnection is failed ?
is authority ? is thread ?

i use the code in apk with JNI .

[sorccu]

Normal applications don't have permission to access SurfaceComposerClient. Only system apps can do it, or you can try rooting your device. Alternatively, if you're OK with supporting only Android 5.0+, try adding the CAPTURE_VIDEO_OUTPUT permission. I haven't tried it myself but it might work. Although if you're OK with 5.0+, you should use the official public APIs instead.

[workzj]

but,my device is root . and i run app on android 4.4. is any other reason?

[sorccu]

Does your app run as root?

[workzj]

yes, this is my test code:

JNIEXPORT jint JNICALL Java_com_hupo_Screenshot(JNIEnv *jPE, jobject jo, jint jiX, jint jiY)
{
    int result = system("su");
    if (result == -1)
    {
        return -1;
    }

    ProcessState::self()->startThreadPool();

    ScreenshotClient mScreenshotClient;

    sp<android::CpuConsumer> mConsumer;
    sp<android::IBinder> mVirtualDisplay;
    CpuConsumer::LockedBuffer mBuffer;
    sp<FrameProxy> mFrameProxy;
    status_t err;

    DisplayInfo dinfo;
    /*
    sp<android::IBinder> dpy = SurfaceComposerClient::getBuiltInDisplay(DEFAULT_DISPLAY_ID);
    err = SurfaceComposerClient::getDisplayInfo(dpy, &dinfo);

    if (err != NO_ERROR) {
        LOGD("SurfaceComposerClient::getDisplayInfo() failed: %s (%d)\n", error_name(err), err);
        return err;
    }*/

    //test code
    sp<ISurfaceComposer> sm(ComposerService::getComposerService());
    if (sm != 0) {
        sp<ISurfaceComposerClient> conn = sm->createConnection();
        if (conn != 0) {
            LOG("init success ... ");
            return 1;
        }
        LOG("conn == 0");
        return -1;
    }

    return -1;
}

[sorccu]

That's not how su works... you only get root permissions inside su's child processes. Your code doesn't do anything.

[sorccu]

Also what does this have to do with minicap?

[workzj]

this is my test code , because of my original code :
// Create a Surface for the virtual display to write to.
LOG("Creating SurfaceComposerClient");
android::spandroid::SurfaceComposerClient sc = new android::SurfaceComposerClient();

LOG("Performing SurfaceComposerClient init check");
if ((err = sc->initCheck()) != android::NO_ERROR) {
    LOGD("Unable to initialize SurfaceComposerClient failed: %s (%d)", error_name(err), err);
    return err;
}

is " Unable to initialize SurfaceComposerClient ".so i write this test.

[sorccu]

I see. Well, you need to fix your su usage somehow, but if you get that fixed I think it will work.

[workzj]

i don't understand ... you means , my app has not get the root authority ?

[sorccu]

Yes, because that's not how su works.

[workzj]

thank you ~! i try