Android demo compile issues

[Jasonvdb]

Steps to reproduce:

• Used these instructions to build the artifacts on ubuntu using docker.
• Copied artifacts/android/library-debug.aar into demo/android/app/libs/
• Open /demo/android in Android Studio and build project

Build error:

/Users/jason/Documents/Repositories/rgb/rgb-sdk/demo/android/app/src/main/java/org/lnpbp/demoapp/DemoApp.java:6: error: package org.lnpbp.rgbnode does not exist
import org.lnpbp.rgbnode.Runtime;
                        ^

I noticed org.lnpbp.rgbnode.Runtime does not exist but org.lnpbp.rgb.Runtime does so I made these changes and I get the app to build but it then crashes on first open with this run error:

I/DemoApp: Loading 'rgb_node' library
E/DemoApp: Error loading 'rgb_node' library: java.lang.UnsatisfiedLinkError: dlopen failed: library "librgb_node.so" not found
E/g.lnpbp.demoap: No implementation found for long org.lnpbp.rgb_autogen.rgbJNI.rgb_node_run(java.lang.String, java.lang.String, java.lang.String, short) (tried Java_org_lnpbp_rgb_1autogen_rgbJNI_rgb_1node_1run and Java_org_lnpbp_rgb_1autogen_rgbJNI_rgb_1node_1run__Ljava_lang_String_2Ljava_lang_String_2Ljava_lang_String_2S)
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: org.lnpbp.demoapp, PID: 7455
    java.lang.UnsatisfiedLinkError: No implementation found for long org.lnpbp.rgb_autogen.rgbJNI.rgb_node_run(java.lang.String, java.lang.String, java.lang.String, short) (tried Java_org_lnpbp_rgb_1autogen_rgbJNI_rgb_1node_1run and Java_org_lnpbp_rgb_1autogen_rgbJNI_rgb_1node_1run__Ljava_lang_String_2Ljava_lang_String_2Ljava_lang_String_2S)
        at org.lnpbp.rgb_autogen.rgbJNI.rgb_node_run(Native Method)
        at org.lnpbp.rgb_autogen.rgb.rgb_node_run(rgb.java:57)
        at org.lnpbp.rgb.Runtime.<init>(Runtime.java:24)
        at org.lnpbp.demoapp.DemoApp.onCreate(DemoApp.java:32)
        at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1192)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:6712)
        at android.app.ActivityThread.access$1300(ActivityThread.java:237)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1913)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

[dr-orlovsky]

The crash seems to be another naming-related issue. Will try to fix

[dr-orlovsky]

Ok, this is not the naming issue. It just can't find the library in runtime, i.e. it is not copied as a part of APK: E/DemoApp: Error loading 'rgb_node' library: java.lang.UnsatisfiedLinkError: dlopen failed: library "librgb_node.so" not found

[dr-orlovsky]

Working on replicating all the steps. BTW, you get this error on device or in simulator? And are you using Java or already React Native?

[Jasonvdb]

Have managed to get the same error on a device and simulator.

For this error I'm using the Java Android demo in this repo. I do have a react-native wrapper that is working for iOS so far. If I can get this demo working then it should be simple enough to fix for react-native as well.

[dr-orlovsky]

From what I see by looking inside .aar package is that the binary library called librgb.so and not librgb_node.so (while Android is looking for librgb_node.so as error message says). Don't know how to change that part, I assume this is something gradle-related. Any ideas?

[dr-orlovsky]

... considering of renaming librgb.so back into librgb_node.so. This renaming was mostly accidential and I see has broken many things

[Jasonvdb]

I thought maybe just changing this line final String libName = "rgb_node"; to use rgb instead of rgb_node would work but I then get the this error:

E/DemoApp: Error loading 'rgb' library: java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "_ZNSt12length_errorD1Ev" referenced by "/data/app/~~LN6GpR4dsQOH6xN0_cqfNA==/org.lnpbp.demoapp-1eB-I4WLe5-ims5tw7RtTA==/lib/x86/librgb.so"...
E/g.lnpbp.demoap: No implementation found for long org.lnpbp.rgb_autogen.rgbJNI.rgb_node_run(java.lang.String, java.lang.String, java.lang.String, short) (tried Java_org_lnpbp_rgb_1autogen_rgbJNI_rgb_1node_1run and Java_org_lnpbp_rgb_1autogen_rgbJNI_rgb_1node_1run__Ljava_lang_String_2Ljava_lang_String_2Ljava_lang_String_2S)

I can't see where else to fix the name, there's nothing in the gradle file it seems.

[dr-orlovsky]

Ok, figured out the reason of the second error. Now actually it finds the library, however swig (after update?) generates incorrect binding linking uchar/byte to short (which is two bytes). Figuring out how to fix.

[dr-orlovsky]

E/DemoApp: Error loading 'rgb' library: java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "_ZNSt12length_errorD1Ev" referenced by "/data/app/~~LN6GpR4dsQOH6xN0_cqfNA==/org.lnpbp.demoapp-1eB-I4WLe5-ims5tw7RtTA==/lib/x86/librgb.so"...

Spent a day investigating & trying to fix. No success so far; however what I have found out:

1. Error is a library linking error: it happens before any function inside the app or inside the library is called and before the app has actually started.
2. Error is independent from library name: I tried both librgb and librgb_node. Error and happens only when library named in the correct way (if the library named incorrectly we have the other, originally reported issue).
3. Changing function name and it's arguments does not fix the issue; it continues to happen for the new function
4. The symbol mentioned in the error text (length_error) is absent from the code and I have no idea why it is required and how it should be used.
5. Improving/changing swig.i does not affect error.

[dr-orlovsky]

Ok, this seems to be an Android NDK issue: android/ndk#833

Strange we had not it before. Will try to fix by switching to c++_static library.