Second display not working in Release APK

[ziakhan110]

Describe the bug
When we make release APK , second display does not work.

[VNAPNIC]

u run "flutter build apk --release" right?

[ziakhan110]

Yes i did that,
When app is running i get this,

Tried to automatically register plugins with FlutterEngine (io.flutter.embedding.engine.FlutterEngine@4748c80) but could not find and invoke the GeneratedPluginRegistrant.

[ziakhan110]

the problem might be related to proguard shrinking

[VNAPNIC]

i don't use proguard shrinking in the project.
u can add to manifest

<meta-data
    android:name="flutterEmbedding"
    android:value="2" />

[MarcoGolin]

on debug work normaly, same problem here when run "Flutter run --release"

[ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: PlatformException(showPresentation, Value null at displayId of type org.json.JSONObject$1 cannot be
converted to int, null, null)
E/flutter ( 6899): #0 StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:597)
E/flutter ( 6899): #1 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:158)
E/flutter ( 6899):

[VNAPNIC]

@MarcoGolin What device are you using?
I think maybe both devices are not connected yet

[MarcoGolin]

@MarcoGolin What device are you using?
I think maybe both devices are not connected yet

is the Sunmi D2-mini

[VNAPNIC]

Sunmi D2-mini i think u should use flutter_nearby_connections for it
We're use flutter_nearby_connections for D2-mini in the my project

[ziakhan110]

i don't use proguard shrinking in the project.
u can add to manifest

<meta-data
    android:name="flutterEmbedding"
    android:value="2" />

my project is already using V2

[vagers2000]

Same error to me, release apk is not working and at same place debug one is working.

[mjafartp]

Same issue,
Not working on the release version.

[EbramTawfik]

Worked for me by adding a progaurd rule

-keep class com.namit.** { *; }

[arbyazra123]

its because flutter release mode using obfuscating code on it, and DisplayJson.kt in native code will be obfuscated.
But I fixed this issue by using klutzy way haha,
try this https://github.com/arbyazra123/presentation-displays,
I changed the parameter in native android to a = displayId, b = flags, c = rotation, d = displayName, because the compiler obfuscate the fields of DisplayJson.kt, and I tried to generalize it.

Or you may use the way above me to avoid obfuscating code by using -keep class com.namit.** { *; }

[azhura14]

i was use two condition but nothing change

[ziakhan110]

https://developer.android.com/reference/android/support/annotation/Keep
Use this to ignore the DisplayJson.kt from obfuscating.

[ziakhan110]

Another solution will be to use GSON field name annotations on the DisplayJson.kt fields, this way if the variable name changes the annotated name will remain , and it will work fine.

[johnfriend88]

i have added the -keep class com.namit.** { *; } in proguard . but when i release the apk, the get display shows "null null"

but works with debug mode.

Release mode error:

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Null check operator used on a null value
#0 _DisplayManagerScreenState._getDisplays... (package:hi/test_project.dart:232)
#1 List.forEach (dart:core-patch/growable_array.dart:416)
#2 _DisplayManagerScreenState._getDisplays.. (package:hi/test_project.dart:231)
#3 State.setState (package:flutter/src/widgets/framework.dart:1203)
#4 _DisplayManagerScreenState._getDisplays. (package:hi/test_project.dart:226)

Even when i open example app in release mode, it will show null, null..

I am new to this. could you please help me on this?

[hrueger]

It seems like with the latest flutter, that problem also exists in the example app... Just clone the repo, run flutter pub get, cd example, flutter build apk --release and install the apk. Get Displays returns null, null, null, null...

[patelnirav48]

@VNAPNIC Could you please help here. When we test using release apk its not working

[hrueger]

@patelnirav48 I'm using @arbyazra123's fork successfully (#7 (comment))

[patelnirav48]

@hrueger I'm using iMin device (connected through HDMI) will it work on that too?

[hrueger]

I have no idea - try it and report your findings ;-)

[patelnirav48]

@hrueger Tested, and it works. Thanks a lot.

[dan8551]

displays_manager.dart line 68-70:
displays.add(kReleaseMode ? displayReleaseFromJson(map as Map<String, dynamic>) : displayFromJson(map as Map<String, dynamic>));

What is the reason for this code? It changes the list keys, breaking the code in release

[ziakhan110]

This code is not needed. The author used obfuscated keys for parsing json, but those keys change on each compilation.
The actual soltion is to add this file to prguard rules file to not be obfuscated in release.

Check it here
#42

[ziakhan110]

Here is prguard rules, this should be added to the readme.md of this library so people know its needed in release apk.

-keep class com.namit.** { *; }

[khamenkhai]

When i release the apk file, the secondary display didn't work.Why?? Please tell me

[khamenkhai]

Hello guys, please help me when I release the apk the second display didn't work.Only worked in the debug apk.why is that??

[patelnirav48]

I'm using @arbyazra123's fork successfully (#7 (comment))

Check @arbyazra123's fork (#7 (comment))
It worked for me.

[ejjat0909]

-keep class com.namit.** { *; }

not working

[ejjat0909]

its because flutter release mode using obfuscating code on it, and DisplayJson.kt in native code will be obfuscated. But I fixed this issue by using klutzy way haha, try this https://github.com/arbyazra123/presentation-displays, I changed the parameter in native android to a = displayId, b = flags, c = rotation, d = displayName, because the compiler obfuscate the fields of DisplayJson.kt, and I tried to generalize it.

Or you may use the way above me to avoid obfuscating code by using -keep class com.namit.** { *; }

I have tried to run your project, its not working