[BUG] Unhandled exception: FormatException: Invalid number (at character 1)

[ProgrammingLife]

ℹ️ Info

Flutter 2.8.1
Flutter Launcher Icons: 0.9.2
Dart 2.15.1
Linux

💬 Description

 » flutter pub run flutter_launcher_icons:main
  ════════════════════════════════════════════
     FLUTTER LAUNCHER ICONS (v0.9.1)                               
  ════════════════════════════════════════════
  

✓ Successfully generated launcher icons
Unhandled exception:
FormatException: Invalid number (at character 1)

^

#0      int._handleFormatError (dart:core-patch/integers_patch.dart:129:7)
#1      int.parse (dart:core-patch/integers_patch.dart:55:14)
#2      minSdk (package:flutter_launcher_icons/android.dart:310:18)
#3      createIconsFromConfig (package:flutter_launcher_icons/main.dart:94:47)
#4      createIconsFromArguments (package:flutter_launcher_icons/main.dart:60:7)
#5      main (file:///home/denis/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/bin/main.dart:6:26)
#6      _delayEntrypointInvocation.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:295:32)
#7      _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:192:12)
pub finished with exit code 255

📜 Pubspec.yaml

dependencies:
  flutter:
    sdk: flutter
  path_provider: ^2.0.8
  flutter_launcher_icons: ^0.9.2

# ....

flutter_icons:
  android: "launcher_icon"
  ios: true
  # image_path: "assets/icon/icon_512x512.png"
  image_path: "assets/icon/icon.png"
  remove_alpha_ios: true

[ProgrammingLife]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

[cklanac]

I just got the same error and fixed it by manually setting the minSdkVersion in android/app/build.gradle

    defaultConfig {
        applicationId "com.example.foo"
        minSdkVersion 16 // <<== set this
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

New Flutter projects now have the minSdkVersion set to flutter.minSdkVersion which (currently) resolves to 16 but it appears the package does not pick up that value.

EDIT: Note, minSDKVersion 16 is the bare minimum. Some apps may require a higher minimum for like 19 or even 21 depending on what plugins you have installed (e.g. WebView, Google Maps and several FlutterFire plugins etc.)

[bulanni00]

ndroid.

Good

[bulanni00]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

Good 这个方法简单有效

[phadtrapong]

Hi guys, Is there any suggestion for longterm solution ? I would like to help fix this.

[krin-san]

Since Flutter 2.8 minSdkVersion value is defined local.properties file. Changing the following in constants.dart fixes it:

-const String androidGradleFile = 'android/app/build.gradle';
+const String androidGradleFile = 'android/local.properties';

For the proper fix it'll be better to rename this property as well.

[kiokumicu]

Still not working for me (

[chrystoffer]

changing the file "android/app/build.gradle" did not work for me...
changing the file "flutter_launcher_icons-0.9.2/lib/android.dart" worked successfully! 👍 :) tks!

flutter 2.8.1

[RicardoCLake]

For me, just the "flutter_launcher_icons-0.9.2/lib/android.dart" hint wasn't helpful, but ,when i changed also the "android/app/build.gradle", it worked.

[kiokumicu]

changing the file "flutter_launcher_icons-0.9.2/lib/android.dart" worked successfully! 👍 :) tks!

Maybe it's good if it's working, but I think it's not a good decision )

[chrystoffer]

changing the file "flutter_launcher_icons-0.9.2/lib/android.dart" worked successfully! 👍 :) tks!

Maybe it's good if it's working, but I think it's not a good decision )

not the best option but needed to release an app :(

[Areopagitics]

it would be nice if flutter had the option to set it in the pubspec.yaml, since flutter supports all the way to minSdk 16, and it would be nice to choose.

[cobategit]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

its work for me, i just change minSkdVersion.
before : minSdkVersion 21
after : minSdkVersion '21'
and worked.

[manyeagaf]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

Could you please explain? Where can i locate this path?

[ahzam-shahnil]

For Upcoming Users, here a simple fix:
If you don't have a flutter.minSdkVersion property, then add it to local.properties file:

flutter.minSdkVersion=21

After That go to app/build.gradle file and add this if not present:

def flutterMinSdkVersion = localProperties.getProperty('flutter.minSdkVersion')
if (flutterMinSdkVersion == null) {
    flutterMinSdkVersion = flutter.minSdkVersion.toString()
}

Then in default config: edit it like this:

 defaultConfig {
        applicationId 'com.example'
        minSdkVersion flutterMinSdkVersion.toString()
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

Then run :

flutter clean

Then run the flutter launcher icon command:

flutter pub get
flutter pub run flutter_launcher_icons:main

[cacothi]

I couldn't still make it work in the new Flutter Version (it did work on the previous version tho)

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 2.8.1, on macOS 12.0.1 21A559 darwin-arm, locale en-AU)
[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
[✓] Xcode - develop for iOS and macOS (Xcode 13.2.1)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2020.3)
[✓] VS Code (version 1.63.2)
[✓] Connected device (5 available)

flutter pub run flutter_launcher_icons:main
════════════════════════════════════════════
FLUTTER LAUNCHER ICONS (v0.9.1)
════════════════════════════════════════════

✓ Successfully generated launcher icons
Unhandled exception:
FormatException: Invalid number (at character 1)

^

#0 int._handleFormatError (dart:core-patch/integers_patch.dart:129:7)
#1 int.parse (dart:core-patch/integers_patch.dart:55:14)
#2 minSdk (package:flutter_launcher_icons/android.dart:309:18)
#3 createIconsFromConfig (package:flutter_launcher_icons/main.dart:94:47)
#4 createIconsFromArguments (package:flutter_launcher_icons/main.dart:60:7)

[ahzam-shahnil]

Did you followed exact steps . I would like to see you edited configuration

[ahzam-shahnil]

Did run flutter clean after you edited the build file. It is important to do that.

[cacothi]

I did them all. I’ve actually ended up doing all the changes manually. Which was easy tho. It’s a shame they haven’t fixed it yet. It seems the repo is abandoned.

On Thu, 27 Jan 2022 at 8:14 pm, Ahzam Shahnil ***@***.***> wrote: Did run flutter clean after you edited the build file. It is important to do that. — Reply to this email directly, view it on GitHub <#324 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC4AGTYRZ37GJK3NN72LJA3UYELH5ANCNFSM5LKA262Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.Message ID: ***@***.***>

-- Sent from iPhone

[zetsu01]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart):

From

int minSdk() {
  final File androidGradleFile = File(constants.androidGradleFile);
  final List<String> lines = androidGradleFile.readAsLinesSync();
  for (String line in lines) {
    if (line.contains('minSdkVersion')) {
      // remove anything from the line that is not a digit
      // final String minSdk = '16';
      final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      return int.parse(minSdk);
    }
  }
  return 0; // Didn't find minSdk, assume the worst
}

To

int minSdk() {
  final File androidGradleFile = File(constants.androidGradleFile);
  final List<String> lines = androidGradleFile.readAsLinesSync();
  for (String line in lines) {
    if (line.contains('minSdkVersion')) {
      // remove anything from the line that is not a digit
      // final String minSdk = '16';
      final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
       
      // add new code
      try {
        return int.parse(minSdk);
      } on FormatException catch (_) {
        printStatus("minSdk '${minSdk}' cannot be parsed as int...");
      }
    }
  }
  return 0; // Didn't find minSdk, assume the worst
} 

Follow this link to see [PR submited by marcobazzani ](#88 (comment))

[tdkehoe]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

Could you please explain? Where can i locate this path?

On my macBook it was in development > flutter > .pub-cache etc. shift-command-. (period) hides and shows files that start with . (period).

[matievisthekat]

i was also experiencing this error.

version info:

Flutter 2.10.0 • channel stable • https://github.com/flutter/flutter
Framework • revision 5f105a6ca7 (8 days ago) • 2022-02-01 14:15:42 -0800
Engine • revision 776efd2034
Tools • Dart 2.16.0 • DevTools 2.9.2

i fixed it by manually setting minSdkVersion 21 in android/app/build.gradle

[naveenlearner38]

I just got the same error and fixed it by manually setting the minSdkVersion in android/app/build.gradle

    defaultConfig {
        applicationId "com.example.foo"
        minSdkVersion 16 // <<== set this
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

New Flutter projects now have the minSdkVersion set to flutter.minSdkVersion which (currently) resolves to 16 but it appears the package does not pick up that value.

EDIT: Note, minSDKVersion 16 is the bare minimum. Some apps may require a higher minimum for like 19 or even 21 depending on what plugins you have installed (e.g. WebView, Google Maps and several FlutterFire plugins etc.)

This is working perfectly. New Version of Flutter there is no sdk mentioned directly. That is the problem here.

[RedMillLtd]

I managed to make a change that allows me to use the local.properties file still. The problem is the .contains condition, in my case it was picking up the def and so I needed to change it to .startsWith

For example the line below was being caught as the minSDKVersion
def flutterMinSdkVersion = localProperties.getProperty('flutter.minSdkVersion')

Ended up changing the minSdk() method to the following:

/// Retrieves the minSdk value from the Android build.gradle file
int minSdk() {
  final File androidGradleFile = File(constants.androidGradleFile);
  final List<String> lines = androidGradleFile.readAsLinesSync();
  for (String line in lines) {
    if (line.startsWith('minSdkVersion')) {
      // remove anything from the line that is not a digit
      // final String minSdk = '16';
      final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
       
      // add new code
      try {
        return int.parse(minSdk);
      } on FormatException catch (_) {
        printStatus("minSdk '${minSdk}' cannot be parsed as int...");
      }
    }
  }
  return 0; // Didn't find minSdk, assume the worst
} 

[jishnutv]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

Could you please explain? Where can i locate this path?

In windows C:\flutter\ .pub-cache\hosted\pub.dartlang.org\flutter_launcher_icons-0.9.2\lib
After editing android.dart file run flutter pub get and flutter pub run flutter_launcher_icons:main

[cacothi]

It seems this library is abandoned.

On Fri, 18 Feb 2022 at 7:24 am, Jishnu T V ***@***.***> wrote: Solved with replacing this line (~/flutter/.pub-cache/hosted/ pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308): // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), ''); // To this: final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), ''); That's so stupid I know. But why not? If it's only for the one time of using it. Could you please explain? Where can i locate this path? In windows C:\flutter.pub-cache\hosted\pub.dartlang.org \flutter_launcher_icons-0.9.2\lib After editing android.dart file run flutter pub get and flutter pub run flutter_launcher_icons:main — Reply to this email directly, view it on GitHub <#324 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AC4AGT2JYJWWOPHHIHDQXJDU3VRQPANCNFSM5LKA262Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.Message ID: ***@***.***>

-- Sent from iPhone

[erlangparasu]

i got this error too because the plugin read line that contains comment
in my case look like this:

// minSdkVersion flutter.minSdkVersion
// targetSdkVersion flutter.targetSdkVersion
minSdkVersion 21
targetSdkVersion 30

the error trown because the lib still read the commented line because it contains "minSdkVersion" string

so the current solution i just flip it to:

minSdkVersion 21
targetSdkVersion 30
// minSdkVersion flutter.minSdkVersion
// targetSdkVersion flutter.targetSdkVersion

now it read the first line that contains "minSdkVersion" and it works

i also already create a PR to solve the comment problem
#340

[trspsb]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

it's work for me. thx

[abakhbakh]

I just got the same error and fixed it by manually setting the minSdkVersion in android/app/build.gradle

    defaultConfig {
        applicationId "com.example.foo"
        minSdkVersion 16 // <<== set this
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

New Flutter projects now have the minSdkVersion set to flutter.minSdkVersion which (currently) resolves to 16 but it appears the package does not pick up that value.

EDIT: Note, minSDKVersion 16 is the bare minimum. Some apps may require a higher minimum for like 19 or even 21 depending on what plugins you have installed (e.g. WebView, Google Maps and several FlutterFire plugins etc.)

your solution worked for me, thanks

[hoonblizz]

// final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
// To this:
final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

This worked perfectly.
For the record, my OSX says .pub-cache is located in <username>/.pub-cache.
Of course "showing hidden files" must be activated by CMD + SHIFT + . (DOT)

[girish54321]

i got this error too because the plugin read line that contains comment in my case look like this:

// minSdkVersion flutter.minSdkVersion
// targetSdkVersion flutter.targetSdkVersion
minSdkVersion 21
targetSdkVersion 30

the error trown because the lib still read the commented line because it contains "minSdkVersion" string

so the current solution i just flip it to:

minSdkVersion 21
targetSdkVersion 30
// minSdkVersion flutter.minSdkVersion
// targetSdkVersion flutter.targetSdkVersion

now it read the first line that contains "minSdkVersion" and it works

i also already create a PR to solve the comment problem #340

Only this worked for me ❤️ @erlangparasu

[CriandoGames]

int minSdk() {
final File androidGradleFile = File(constants.androidGradleFile);
final List lines = androidGradleFile.readAsLinesSync();
for (String line in lines) {
if (line.contains('minSdkVersion')) {
// remove anything from the line that is not a digit
final String minSdk = 21.toString();
return int.parse(minSdk);
}
}
return 0; // Didn't find minSdk, assume the worst
}

[YouSour]

i fix it by this :

 flutter_launcher_icons:
    git:
      url: https://github.com/Davenchy/flutter_launcher_icons.git
      ref: fixMinSdkParseFlutter2.8

[dthuesen]

flutter_launcher_icons:
git:
url: https://github.com/Davenchy/flutter_launcher_icons.git
ref: fixMinSdkParseFlutter2.8

YAEH!!!!!!! That really worked!!!

[mahanmarwat]

I fix it by this:

 flutter_launcher_icons:
    git:
      url: https://github.com/Davenchy/flutter_launcher_icons.git
      ref: fixMinSdkParseFlutter2.8

Yup, Thank you! It worked. <3

[mengtongun]

flutter pub get
flutter pub run flutter_launcher_icons:main

i got this error too because the plugin read line that contains comment in my case look like this:

// minSdkVersion flutter.minSdkVersion
// targetSdkVersion flutter.targetSdkVersion
minSdkVersion 21
targetSdkVersion 30

the error trown because the lib still read the commented line because it contains "minSdkVersion" string

so the current solution i just flip it to:

minSdkVersion 21
targetSdkVersion 30
// minSdkVersion flutter.minSdkVersion
// targetSdkVersion flutter.targetSdkVersion

now it read the first line that contains "minSdkVersion" and it works

i also already create a PR to solve the comment problem #340

It worked for me Thank you!

[HoangHieuS]

i fix it by this :

 flutter_launcher_icons:
    git:
      url: https://github.com/Davenchy/flutter_launcher_icons.git
      ref: fixMinSdkParseFlutter2.8

It worked for me Thank you!

[jdemorcy]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

Could you please explain? Where can i locate this path?

In windows C:\flutter\ .pub-cache\hosted\pub.dartlang.org\flutter_launcher_icons-0.9.2\lib After editing android.dart file run flutter pub get and flutter pub run flutter_launcher_icons:main

Indeed ! don't forget to run 'futter pub get' after editing the file otherwise it won't work ! (took me a while to figure that out...)

[owieth]

i fix it by this :

 flutter_launcher_icons:
    git:
      url: https://github.com/Davenchy/flutter_launcher_icons.git
      ref: fixMinSdkParseFlutter2.8

Thanks mate :D Works like a charm

[ldurniat]

i fix it by this :

 flutter_launcher_icons:
    git:
      url: https://github.com/Davenchy/flutter_launcher_icons.git
      ref: fixMinSdkParseFlutter2.8

Why this work and how?:)

[saqibhaneef]

For Upcoming Users, here a simple fix: If you don't have a flutter.minSdkVersion property, then add it to local.properties file:

flutter.minSdkVersion=21

After That go to app/build.gradle file and add this if not present:

def flutterMinSdkVersion = localProperties.getProperty('flutter.minSdkVersion')
if (flutterMinSdkVersion == null) {
    flutterMinSdkVersion = flutter.minSdkVersion.toString()
}

Then in default config: edit it like this:

 defaultConfig {
        applicationId 'com.example'
        minSdkVersion flutterMinSdkVersion.toString()
        targetSdkVersion flutter.targetSdkVersion
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

Then run :

flutter clean

Then run the flutter launcher icon command:

flutter pub get
flutter pub run flutter_launcher_icons:main

This worked for me

[macro6461]

i fix it by this :

 flutter_launcher_icons:
    git:
      url: https://github.com/Davenchy/flutter_launcher_icons.git
      ref: fixMinSdkParseFlutter2.8

Why this work and how?:)

It is directly depending on a Git Repository and branch that was forked from the original flutter_launcher_icons. You can find it here.

[kujin521]

int minSdk() {
final File androidGradleFile = File(constants.androidGradleFile);
final List lines = androidGradleFile.readAsLinesSync();
for (String line in lines) {
if (line.contains('minSdkVersion')) {
// remove anything from the line that is not a digit
//final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
//return int.parse(minSdk);
return 21;《《good
}
}
return 0; // Didn't find minSdk, assume the worst
}

[O-sura]

Solved this by changing the minSdkVersion

[mammad-xero]

Solved with replacing this line (~/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart#308):

      // final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      // To this:
      final String minSdk = "21"; // line.replaceAll(RegExp(r'[^\d]'), '');

That's so stupid I know. But why not? If it's only for the one time of using it.

This solution worked for me❤️❤️👌

[edx86]

The reason it fails is because the script just checks the first ocurrence of 'minSdkVersion':

Path <path-to-flutter>/.pub-cache/hosted/pub.dartlang.org/flutter_launcher_icons-0.9.2/lib/android.dart

Excerpt:

/// Retrieves the minSdk value from the Android build.gradle file
int minSdk() {
  final File androidGradleFile = File(constants.androidGradleFile);
  final List<String> lines = androidGradleFile.readAsLinesSync();
  for (String line in lines) {
    if (line.contains('minSdkVersion')) {
      print("line = '$line'");    // <<< [HERE] the output is: line = 'def flutterMinSdkVersion = localProperties.getProperty('flutter.minSdkVersion')'
      // remove anything from the line that is not a digit
      final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      return int.tryParse(minSdk);
    }
  }
  return 0; // Didn't find minSdk, assume the worst
}

So how to make a workaround? See 2 options below:

Option 1 - change in project code

If you have the following code in android/app/build.gradle:

def flutterMinSdkVersion = localProperties.getProperty('flutter.minSdkVersion')
if (flutterMinSdkVersion == null) {
    flutterMinSdkVersion = 21
}

remove it and hardcode minSdkVersion directly in

defaultConfig {
    //...
    minSdkVersion 21     // flutterMinSdkVersion
}

Option 2 - patch cached library

Use power of 'if null' operator?? in Dart like this:

/// Retrieves the minSdk value from the Android build.gradle file
int minSdk() {
  final File androidGradleFile = File(constants.androidGradleFile);
  final List<String> lines = androidGradleFile.readAsLinesSync();
  for (String line in lines) {
    if (line.contains('minSdkVersion')) {
      // remove anything from the line that is not a digit
      final String minSdk = line.replaceAll(RegExp(r'[^\d]'), '');
      return int.tryParse(minSdk) ?? 21;       // <<< [HERE] Change 'int.parse' to 'int.tryParse' and specify minimal version you like
    }
  }
  return 0; // Didn't find minSdk, assume the worst
}

NOTE: I didn't check what's the minimal version of minSdk, but for my project I use version of 21 and it works.

[TheBeachMaster]

None of the above solutions worked for me

For anybody looking for a quick and harmless fix,

Navigate to android/local.properties and add

flutter.minSdkVersion=16

[ged-flod]

I just changed the package version and that solved the problem for me.

dependencies:
  flutter_launcher_icons: ^0.10.0