Webview app crashes when trying to request permissions

[frnsys]

Checklist

• the issue is indeed a bug and not a support request
• issue doesn't already exist: https://github.com/kivy/python-for-android/issues
• I have a short, runnable example that reproduces the issue
• I reproduced the problem with the latest development version (p4a.branch = develop)
• I used the grave accent (aka backticks) to format code or logs when appropriated

Versions

• Python: 3.6.6
• OS: Ubuntu 20.04
• python-for-android: 2020.6.2

Description

I'm building with:

HERE=$(pwd)
cd app

export ANDROIDSDK="$HERE/android_sdks"
# Have also tried with
# export ANDROIDNDK="$HERE/android_sdks/android-ndk-r19c"
export ANDROIDNDK="$HERE/android_sdks/android-ndk-r21d"
export ANDROIDAPI="27"  # Target API version of your application
export NDKAPI="21"  # Minimum supported API version of your application

p4a apk --private "." --package=org.anarres.pdfreader --name "pdf reader" --version 0.1 --bootstrap=webview --requirements=python3,flask --port=5000 --orientation=sensor --blacklist="../blacklist.txt" --permission READ_EXTERNAL_STORAGE --permission WRITE_EXTERNAL_STORAGE

My python code is just:

from android.permissions import request_permissions, Permission
request_permissions([Permission.READ_EXTERNAL_STORAGE, Permission.WRITE_EXTERNAL_STORAGE])

from flask import Flask, render_template

app = Flask(__name__)

@app.route('/')
def index():
    return render_template('index.html')

if __name__ == '__main__':
    app.run(port=5000)

If I comment out:

from android.permissions import request_permissions, Permission
request_permissions([Permission.READ_EXTERNAL_STORAGE, Permission.WRITE_EXTERNAL_STORAGE])

I don't see the error, but then of course I can't access the external storage.

Logs

ImportError: dlopen failed: cannot locate symbol "SDL_ANDROID_GetJNIEnv" referenced by "/data/data/org.anarres.pdfreader/files/app/_python_bundle/site-packages/android/_android.so"...

[mnba]

Seems the code in your linked _android.so library by some reason requests SDL_xxx functions while they are not built in, as your bootstrap is webview, and hence the code you built has no SDL functions in it

[frnsys]

Yeah, references to SDL_Android_GetJNIEnv are hard coded in the library: https://github.com/kivy/python-for-android/search?q=SDL_Android_GetJNIEnv. I tried replacing it wherever it shows up with WebView_AndroidGetJNIEnv (which appears to be defined here?) but that led to a similar error:

ImportError: dlopen failed: cannot locate symbol "WebView_AndroidGetJNIEnv" referenced by "/data/data/org.anarres.pdfreader/files/app/_python_bundle/site-packages/android/_android.so"...

[obfusk]

@frnsys I think I managed to fix this in #2340.