Android Question DJI DRONES - ERROR

Roberto P.

Well-Known Member
Licensed User
I resumed my attempt to develop an app for DJI with the libraries of the post:

I was able to activate the app DroneFirst but when it tries to connect from the following error..

**************************** BaseApplication **************************
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
activation listener added
Registered successfully!
No connected product
java.lang.NoClassDefFoundError: Failed resolution of: Landroid/support/v4/util/Pools$SynchronizedPool;
at$a.<clinit>(Unknown Source:0)
at$a.obtain(Unknown Source:0)
at Source:5)
at dji.midware.usb.P3.UsbAccessoryService$1.onGetBody(Unknown Source:304)
at dji.midware.parser.plugins.b.c(Unknown Source:170)
at dji.midware.parser.plugins.b.a(Unknown Source:23)
at dji.midware.usb.P3.UsbAccessoryService$ Source:305)
Caused by: java.lang.ClassNotFoundException: Didn't find class "$SynchronizedPool" on path: DexPathList[[zip file "/system/framework/", zip file "/data/app/b4a.dji.test1-59uId5oyeV6PLep8H92nfw==/base.apk", zip file "/data/user/0/b4a.dji.test1/.cache_sdk/sdkclasses.jar"],nativeLibraryDirectories=[/data/app/b4a.dji.test1-59uId5oyeV6PLep8H92nfw==/lib/arm, /system/fake-libs, /data/app/b4a.dji.test1-59uId5oyeV6PLep8H92nfw==/base.apk!/lib/armeabi-v7a, /system/lib, /system/vendor/lib]]
at dalvik.system.BaseDexClassLoader.findClass(
at java.lang.ClassLoader.loadClass(
at java.lang.ClassLoader.loadClass(
... 8 more
** Activity (main) Pause, UserClosed = true **

can anyone tell me what it refers to?

thank in advance

Roberto P.

Well-Known Member
Licensed User
Hi Manfred
thanks for your reply

but I have the same error

see the code below

#BridgeLogger: true
#MultiDex: true
#AdditionalJar: dji-sdk-provided-4.4.1, ReferenceOnly
#Additionaljar: androidx.legacy:legacy-support-v4
thank for your


Licensed User
i dont see any androidx files here.

anyway i can´t help any further on this. i never used the lib in the last time (about 1,5 years ago). Don´t know if it is maybe incompatible with AndroidX.

Roberto P.

Well-Known Member
Licensed User
I'm working on a new version of DJI library.
Hi Erel
very interesting .... do you have any idea how much you could release it? I would like to develop with B4A and not with Android Studio.

Thanks in advance