proguardLevel 'all' leads to blank black screen

Hi! I try to reduce app size by using proguard.
So I set proguardLevel ‘all’ and add my android proguard rules as appendCfgFile

tasks.withType( {
  task ->
    task.appendCfgFile = file("${rootDir}/../android/proguard-debug.cfg")

Build and deploy works well, but I see just black screen on my device. I don’t see any errors or exceptions in logs. How can I investigate where is a problem?

Dear zufarfakhurtdinov,

android’s ProGuard rules will not be enough. You will need to keep iOS protocol interfaces:

-keep interface apple.uikit.protocol.UIApplicationDelegate { *; }

Best Regards,

I’ve fixed it by add

-keepclassmembers class ** {** public *;

Can I use more strict rule for this?