flutter build apk 

Initializing gradle...                                              0.9s
Resolving dependencies...

⣟ (This is taking an unexpectedly long time.)
⣟ (This is taking an unexpectedly long time.)
⣟ (This is taking an unexpectedly long time.)
⣟ (This is taking an unexpectedly long time.)

[✓] Flutter (Channel stable, v1.2.1, on Linux, locale en_US.UTF-8)
    • Flutter version 1.2.1 at /home/alouch/flutter
    • Framework revision 8661d8aecd (9 weeks ago), 2019-02-14 19:19:53 -0800
    • Engine revision 3757390fa4
    • Dart version 2.1.2 (build 2.1.2-dev.0.0 0a7dcf17eb)

[!] Android toolchain - develop for Android devices (Android SDK version 27.0.3)
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    ✗ Flutter requires Android SDK 28 and the Android BuildTools 28.0.3
      To update using sdkmanager, run:
        /home/alouch/Android/Sdk/tools/bin/sdkmanager "platforms;android-28"
        "build-tools;28.0.3"
      or visit https://flutter.io/setup/#android-setup for detailed
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[✓] Android Studio (version 3.2)
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    • Flutter plugin version 24.2.2
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    • Java version OpenJDK Runtime Environment (build
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