Flutter Release apk is not working properly?

I think you need

flutter clean

(I'd consider it a bug that this is necessary, but I'm encountering it as well)

and

flutter build apk --release

If your problem is that the flutter build (APK, bundle) isn't making API calls in a real device, this is because you need to add the Internet permission to Android Manifest before creating the release/build.

By default, "internet use" will work fine on the emulator but not on a real device.

To fix this, simply:

Open the file "android/app/src/main/AndroidManifest.xml" and add the proper user-permission:

<manifest> 
...
 <uses-permission android:name="android.permission.INTERNET"/>
...
</manifest>

And then create your build again.

1. you can change in local.properties android project

       sdk.dir=D:/SDK               //your android SDK location
       flutter.sdk=D:\\Flutter\\flutter  //your flutter SDK location
       flutter.versionName=1.0.0
       flutter.versionCode=2
       flutter.buildMode=release
   

2. changes in your android/app/build.gradle file

        buildTypes {
               release {
                   // if everything ok then not add 
                   //minifyEnabled true 
                   //another you can remove minifyEnabled true
                   proguardFiles getDefaultProguardFile('proguard- 
                    android.txt'), 'proguard-rules.pro'
                   signingConfig signingConfigs.release
               }
           }
   

3. you can also changes in android/app/build.gradle defaultConfig method body.

     multiDexEnabled true
   

4. if you want to migrate to androidx then do it setup.

   dependencies { testImplementation 'junit:junit:4.12' androidTestImplementation 'androidx.test:runner:1.1.1' androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1' implementation 'androidx.multidex:multidex:2.0.1'

   }

   5. and clean before create build folder by following this cmd.

       - flutter clean
      
       - flutter build apk --release
      
       - flutter install
      

6.Release Apk location.

        in `android studio termial` or inside `project-root` you can navigate to this.

        cd build\app\outputs\apk\release