Develop Reference

TensorFlow + AndroidScanner - couldn't find "libopencv_java3.so"

I'm having a problem with combining Tensorflow and AndroidScanner.
I use Tensorflow to display an overlay over the camera feed. I take a picture with the camera, and then send it to a server. It works.
Now I imported the AndroidScannerDemo, I want to use the taken picture and crop/transform it with the newly imported module. It crashes. When I open the ScanActivity (from the AndroidScannerDemo), it tries to load opencv, and never succeeds. The error message is as follows:
FATAL EXCEPTION: main
Process: fr.pacifica.insurancechat.debug, PID: 2139
java.lang.UnsatisfiedLinkError: dalvik.system.PathClassLoader[DexPathList[[zip file "/data/app/fr.pacifica.insurancechat.debug-OI_d1EANbiczpZEwAHYdkw==/base.apk"],nativeLibraryDirectories=[/data/app/fr.pacifica.insurancechat.debug-OI_d1EANbiczpZEwAHYdkw==/lib/arm64, /data/app/fr.pacifica.insurancechat.debug-OI_d1EANbiczpZEwAHYdkw==/base.apk!/lib/arm64-v8a, /system/lib64, /system/vendor/lib64]]] couldn't find "libopencv_java3.so"
at java.lang.Runtime.loadLibrary0(Runtime.java:1011)
at java.lang.System.loadLibrary(System.java:1657)
at com.scanlibrary.ScanActivity.(ScanActivity.java:125)
at java.lang.Class.newInstance(Native Method)
at android.app.Instrumentation.newActivity(Instrumentation.java:1190)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2837)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3046)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1688)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6809)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
When I delete TensorFlow references from gradle/code, the imported module works just fine.

The project you imported, only builds 32-bit versions of libScanner.so, and therefore only uses the 32-bit versions of libopencv_java3.so. In the short run, you can keep that, only set
android {
defaultConfig {
ndk {
abiFilters 'armeabi-v7a'
}
}
}
This will cause your APK run in 32-bit mode on arm64 devices.
In the long run, you should update the Scanner library to build in 64-bit, too. This may have a significant performance gain.
from August 2019, 64-bit support is required for all apps in Play Store

I had the same problem with some mobiles (64 bits processor)
Here is the libs you need for every single arquitecture. You can download it and import manually.
https://github.com/jhansireddy/AndroidScannerDemo/tree/2cd23d3d362d0a6248cf489a79ebc4ba2c425c60/ScanDemoExample/scanlibrary/src/main/libs

How to import Guava into Android applications

What is the proper way to import Guava into an Android project? Every time I try to use it I get a NoClassDefFoundError.
This is what I'm doing to generate the crash. I'm using Android Studio 3.0 Canary 7.
Create an new project File > New > New Project, target API 26.0, using the Empty Activity template.
Add to app/build.gradle in the dependencies section
implementation "com.google.guava:guava:20.0"
Add this to the onCreate method in MainActivity.java
ImmutableList<String> foo = ImmutableList.of("A", "B", "C");
Log.d("MainActivity", foo.get(0));
Run the App and open up Logcat to see this exception:
FATAL EXCEPTION: main
Process: com.letsdoit.guavaissue, PID: 14366
java.lang.NoClassDefFoundError: Failed resolution of: Lcom/google/common/collect/ImmutableList;
at com.letsdoit.guavaissue.MainActivity.onCreate(MainActivity.java:20)
at android.app.Activity.performCreate(Activity.java:6679)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.common.collect.ImmutableList" on path: DexPathList[[zip file "/data/app/com.letsdoit.guavaissue-1/base.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_dependencies_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_0_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_1_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_2_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_3_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_4_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_5_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_6_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_7_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_8_apk.apk", zip file "/data/app/com.letsdoit.guavaissue-1/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/data/app/com.letsdoit.guavaissue-1/lib/x86, /system/lib, /vendor/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
at com.letsdoit.guavaissue.MainActivity.onCreate(MainActivity.java:20) 
at android.app.Activity.performCreate(Activity.java:6679) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:6119) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
I'm almost certain it has to do with Gauva being large and not playing well with multidex, but am not sure what to do about it. These are some of the note worthy things I've tried to no avail:
Enabling multidex and specifying ImmutableList in the multiDexKeepFile.
Disabling instant run.
Pulled the APKs from the device and verified the Guava classes are in the APKs.
Following the recommendations in this stack overflow question.

TL;DR
Use guava version 22.0-android and up. Make sure to use the -android flavor, otherwise you'll run into the NoClassDefFoundError.
Explanation
I learned after posting the question how to manually clean the project and uninstall apks from the emulator. It turns out that version 20.0 actually does work, but I had tried version 21.0 right before then and failed to clean.
The non-android flavors of guava as of version 21.0 are using Java 8. The android flavors and versions before 21.0 use Java 7. This is described in these release notes for version 22.0.
I tested these flavors and versions:
20.0 (Java 7) - works
21.0 (Java 8) - doesn't work
22.0 (Java 8) - doesn't work
22.0-android (Java 7) - works
When using version 21.0 or 22.0 (no -android) the ImmutableList class is getting referenced but not compiled into the dex files (since it's in italics). This was causing the NoClassDefFoundError.
APK with dangling references to ImmutableList
As the android developer docs explain
In the tree view, italicized nodes are references that do not have a
definition in the selected DEX file.
It further explains that
A DEX file can reference methods and fields that are defined in a
different a file. For example System.out.println() is a reference to
the println() method in the Android framework.
But in this case, there is no other file that these methods and class definition should end up in. It's just failing to add them.
Contrast that to using 20.0 or 22.0-android, where the ImmutableList class actually gets compiled in.
APK with ImmutableList defined
And the app starts up as expected.

UnsatisfiedLinkError in pjsip library

I build Pjsip library and use its sample in android studio .
question
When I run that i got this error.How could I solve it ? thanks in advance.
exception
jsip.pjsua2.app E/AndroidRuntime: FATAL EXCEPTION: main
Process: org.pjsip.pjsua2.app, PID: 4360
java.lang.UnsatisfiedLinkError: No implementation found for void org.pjsip.pjsua2.pjsua2JNI.swig_module_init() (tried Java_org_pjsip_pjsua2_pjsua2JNI_swig_1module_1init and Java_org_pjsip_pjsua2_pjsua2JNI_swig_1module_1init__)
at org.pjsip.pjsua2.pjsua2JNI.swig_module_init(Native Method)
at org.pjsip.pjsua2.pjsua2JNI.(pjsua2JNI.java:2351)
at org.pjsip.pjsua2.Endpoint.(Endpoint.java:68)
at org.pjsip.pjsua2.app.MyApp.(MyApp.java:296)
at org.pjsip.pjsua2.app.MainActivity.onCreate(MainActivity.java:92)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2332)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2442)
at android.app.ActivityThread.access$800(ActivityThread.java:156)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5389)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)

It may happen for several reasons. First, check if you attached the native library correctly. For that create a folder named "jniLibs" into the projects
app/src/main/jniLibs
then put your armeabi architecture library like
armeabi/libpjsua2.so
for other architecture like armeabi-v7a use
armeabi-v7a/libpjsua2.so
like this.
there are other reasons may happen. If you build pjsip library for armeabi architecture only and running your application in an x86 architecture device then this error may occur. So check it also if you have built it for that application.

Please take a look at this thread: building pjsua2 dll
the important thing to know here is that the error you show in your question is caused by the fact that the pjsua2.dll (a c++ dll) is not in your output directory.

Visual Studio Xamarin android app crashes

I'm trying to run an android xamarin app in Visual Studio 2013, it deploys normally, but crashes after start.
Here is the log:
java.lang.RuntimeException: Unable to get provider mono.MonoRuntimeProvider: java.lang.RuntimeException: Unable to find application Mono.Android.Platform.ApiLevel_22 or Xamarin.Android.Pla
at android.app.ActivityThread.installProvider(ActivityThread.java:5002)
at android.app.ActivityThread.installContentProviders(ActivityThread.java:4594)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4534)
at android.app.ActivityThread.access$1500(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1364)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.RuntimeException: Unable to find application Mono.Android.Platform.ApiLevel_22 or Xamarin.Android.Platform!
at mono.MonoRuntimeProvider.attachInfo(MonoRuntimeProvider.java:38)
at android.app.ActivityThread.installProvider(ActivityThread.java:4999)
... 11 more
Caused by: android.content.pm.PackageManager$NameNotFoundException: Xamarin.Android.Platform
at android.app.ApplicationPackageManager.getApplicationInfo(ApplicationPackageManager.java:281)
at mono.MonoRuntimeProvider.attachInfo(MonoRuntimeProvider.java:32)
The same thing on emulator with any platform and device.
Thank you in advance.

With the last Xamarin Update i run into this problem as well.
Try disabling "Use shared runtime" in your Android Build options. It seems with the current Version a developent build is not able to call into the shared mono runtime.
--> https://forums.xamarin.com/discussion/52439/unable-to-get-provider-mono-monoruntimeprovider
What helped some others:
Some suggested to just change "Target Version" (and "Compile Version" for VS) and Rebuild. The important part was to have changes in the Project File and not what exactly you changed "Target Version" from and to.
--> https://stackoverflow.com/a/32607524/383658

java.lang.UnsatisfiedLinkError after updating to Android 5.0

I'm developing an Android app which uses a native library called liballjoyn_java.so (available here in the Android Core SDK). I'm using Android Studio as IDE and Maven as build/dependency system (not Gradle). With Android KitKat everything worked like a charm and this is how I added the library to my project:
1) Added the library to my local Maven repo
mvn install:install-file -Dfile=./alljoyn/liballjoyn_java.so -DgroupId=org.alljoyn -DartifactId=liballjoyn_java -Dversion=14.06.00 -Dscope=runtime -Dpackaging=so
2) Defined a dependency in the POM file:
<dependency>
<groupId>org.alljoyn</groupId>
<artifactId>liballjoyn_java</artifactId>
<scope>runtime</scope>
<type>so</type>
<version>14.06.00</version>
</dependency>
3) Called it statically from my code:
static {
try {
System.loadLibrary("alljoyn_java");
Log.d("AllJoynManager", "static - Loaded AllJoyn native library");
} catch (Exception exception) {
Log.d("AllJoynManager", "static - Error loading AllJoyn native library");
exception.printStackTrace();
}
}
This was working perfectly under KitKat in my Nexus 4 phone but now I installed the official Android 5.0 OTA update and I get the following error on runtime:
11-28 17:57:39.988 30068-30068/com.avispalabs.kiihome E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.avispalabs.kiihome, PID: 30068
java.lang.UnsatisfiedLinkError: dalvik.system.PathClassLoader[DexPathList[[zip file "/data/app/com.avispalabs.kiihome-2/base.apk"],nativeLibraryDirectories=[/data/app/com.avispalabs.kiihome-2/lib/arm, /vendor/lib, /system/lib]]] couldn't find "liballjoyn_java.so"
at java.lang.Runtime.loadLibrary(Runtime.java:366)
at java.lang.System.loadLibrary(System.java:989)
at com.avispalabs.kiihome.helpers.network.alljoyn.AlljoynManager.<clinit>(AlljoynManager.java:38)
at com.avispalabs.kiihome.ui.activities.MainActivity.<init>(MainActivity.java:38)
at java.lang.reflect.Constructor.newInstance(Native Method)
at java.lang.Class.newInstance(Class.java:1572)
at android.app.Instrumentation.newActivity(Instrumentation.java:1065)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2199)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
11-28 17:57:55.432 30068-30068/com.avispalabs.kiihome I/Process﹕ Sending signal. PID: 30068 SIG: 9
I suspect the .so library might have been compiled in way which is somehow incompatible with the new Android 5.0 ART (?). The message that says it can't find the library is probably misleading (the exception is also seen when a library fails to load) but I'm not sure (another possibility is the .so is not correctly extracted or placed).
The library comes precompiled and is advertised to be compatible with JellyBean. I thought previous dynamic libraries would be compatible with new versions of Android, otherwise a lot of apps would break. If I install the same APK in a Nexus 4 with KitKat it just works.
Any advice is highly appreciated.
UPDATE: I have tested my project in a KitKat based device and switched the runtime to ART rather than Dalvik, and the project works fine. This problem seems to be tied to Android 5 rather than ART itself.

Answering my own question here. You can solve it by compiling liballjoyn_java as PIE as explained here:
https://jira.allseenalliance.org/browse/ASACORE-1208
This is a workaround until the AllJoyn guys publish a new Android build. Keep an eye here to get the updated release:
https://build.allseenalliance.org/ci/view/Core%20RB14.12%20SDK/job/branch-android-sdk/