Unhandled Exception: MissingPluginException

Flutter
1

Hello. When run application in Release mode, got his error:

[ERROR:flutter/lib/ui/ui_dart_state.cc(209)] Unhandled Exception: MissingPluginException(No implementation found for method Backendless.Data.of.find on channel backendless/data)

E/flutter ( 9802): #0 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:154)
E/flutter ( 9802):
E/flutter ( 9802): #1 MapDrivenDataStore.find (package:backendless_sdk/src/modules/data/data_store.dart:87)
E/flutter ( 9802):
E/flutter ( 9802): #2 _LoadDataState.loadData (package:a2capital_app/pages/load_data.dart:95)
E/flutter ( 9802):
E/flutter ( 9802):

Code example from pages/load_data.dart:95

93: DataQueryBuilder queryBuilder = DataQueryBuilder()
94: …whereClause = “toUser = '”+num+"’";
95: Backendless.data.of(“settings”).find(queryBuilder).then((foundUser) {
…

}

Bug only in Android, Release build.
IOS works perfect, and Android debug build also works good.

All Proguard definitions added:

-dontwarn com.backendless.**
-dontwarn weborb.**
-keep class weborb.** {;}
-keep class com.backendless.** {;}

Error both Backendless SDK 7.1.1 and 7.1.3

2

Hello @A2_Capital

An internal ticket has been created, the ticket’s number for reference is BKNDLSS-26366.
We will update you here once our Flutter engineer takes a look into the issue.

Regarda, Vlad

3

Hello, @A2_Capital.

Sorry for the long delay.
I just tested my Android app in release mode. It worked great for me, and no problem.
Checked on version 7.1.7.
Is this problem relevant to this version for you?
If so, then I assume that you have something wrong with your proguard or gradle setting.
There is my proguard file:

#Flutter Wrapper
-keep class io.flutter.app.** { *; }
-keep class io.flutter.plugin.**  { *; }
-keep class io.flutter.util.**  { *; }
-keep class io.flutter.view.**  { *; }
-keep class io.flutter.**  { *; }
-keep class io.flutter.plugins.**  { *; }
#Backendless
-dontwarn com.backendless.**
-dontwarn weborb.**
-keep class weborb.** {*;}
-keep class com.backendless.** {*;}

There is my app/build.gradle:

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('app/key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '2'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.1'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 30

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
        checkReleaseBuilds false //<- add this line
    }

    defaultConfig {
        applicationId "com.backendless.exampleSupport"
        minSdkVersion 20
        targetSdkVersion 30
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        multiDexEnabled = true
    }

    signingConfigs {
        release {
            keyAlias keystoreProperties['keyAlias']
            keyPassword keystoreProperties['keyPassword']
            storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
            storePassword keystoreProperties['storePassword']
        }
    }

    buildTypes {
        release {
            signingConfig signingConfigs.release

            useProguard true

            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.android.support:multidex:1.0.3'
}

I ran project with flutter run --release command