flet build apk fail

[jk-2022]

Question

I'm getting errors when trying to build the APK, I'm using a Windows 11, Android Studio 2023.1, Flutter SDK 3.16.6

Code sample

import flet as ft


def main(page: ft.Page):
    page.add(ft.SafeArea(ft.Text("Hello, Flet!")))


ft.app(main)

Error message

C:\Users\jk\Desktop\myapp>flet build apk --verbose
Flutter bootstrap directory: C:\Users\jk\AppData\Local\Temp\flet_flutter_build_vrOOwZxpXd
Creating Flutter bootstrap project...OK
Customizing app icons and splash images...Copying C:\Users\jk\Desktop\myapp\assets\icon.png to C:\Users\jk\AppData\Local\Temp\flet_flutter_build_vrOOwZxpXd\images
OK
Generating app icons...OK
Generating splash screens...OK
Packaging Python app...OK
Building .apk for Android...['C:\\flutter\\bin\\flutter.BAT', 'build', 'apk']
Resolving dependencies...
  fl_chart 0.65.0 (0.66.0 available)
  flutter_lints 2.0.3 (3.0.1 available)
  flutter_native_splash 2.3.7 (2.3.9 available)
  js 0.6.7 (0.7.0 available)
  lints 2.1.1 (3.0.0 available)
  matcher 0.12.16 (0.12.16+1 available)
  material_color_utilities 0.5.0 (0.8.0 available)
  meta 1.10.0 (1.11.0 available)
  package_info_plus 4.2.0 (5.0.1 available)
  path 1.8.3 (1.9.0 available)
  petitparser 5.4.0 (6.0.2 available)
  test_api 0.6.1 (0.7.0 available)
  toml 0.14.0 (0.15.0 available)
  web 0.3.0 (0.4.2 available)
  web_socket_channel 2.4.0 (2.4.3 available)
  xml 6.3.0 (6.5.0 available)
Got dependencies!
16 packages have newer versions incompatible with dependency constraints.
Try `flutter pub outdated` for more information.

Running Gradle task 'assembleRelease'...
Running Gradle task 'assembleRelease'...                           585ms

Exception in thread "main" java.util.zip.ZipException: zip END header not found
        at java.base/java.util.zip.ZipFile$Source.findEND(ZipFile.java:1474)
        at java.base/java.util.zip.ZipFile$Source.initCEN(ZipFile.java:1482)
        at java.base/java.util.zip.ZipFile$Source.<init>(ZipFile.java:1320)
        at java.base/java.util.zip.ZipFile$Source.get(ZipFile.java:1282)
        at java.base/java.util.zip.ZipFile$CleanableResource.<init>(ZipFile.java:709)
        at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:243)
        at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:172)
        at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:186)
        at org.gradle.wrapper.Install.unzip(Install.java:214)
        at org.gradle.wrapper.Install.access$600(Install.java:27)
        at org.gradle.wrapper.Install$1.call(Install.java:74)
        at org.gradle.wrapper.Install$1.call(Install.java:48)
        at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
        at org.gradle.wrapper.Install.createDist(Install.java:48)
        at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
        at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
Gradle task assembleRelease failed with exit code 1

Deleting Flutter bootstrap directory C:\Users\jk\AppData\Local\Temp\flet_flutter_build_vrOOwZxpXd
Error building Flet app - see the log of failed command above.

------------------------------------------------------

• I have searched for answers to my question both in the issues and in previous discussions.

[FeodorFitsner]

Looks like it can't download Gradle distro?

[jk-2022]

Yes

[deeplook]

I'm running into the same error on macOS, even after brew-installing flutter, java and gradle with an installation log ending like this:

Exception in thread "main" java.util.zip.ZipException: zip END header not found
        at java.base/java.util.zip.ZipFile$Source.findEND(ZipFile.java:1649)
        at java.base/java.util.zip.ZipFile$Source.initCEN(ZipFile.java:1657)
        at java.base/java.util.zip.ZipFile$Source.<init>(ZipFile.java:1495)
        at java.base/java.util.zip.ZipFile$Source.get(ZipFile.java:1458)
        at java.base/java.util.zip.ZipFile$CleanableResource.<init>(ZipFile.java:724)
        at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:251)
        at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:180)
        at java.base/java.util.zip.ZipFile.<init>(ZipFile.java:194)
        at org.gradle.wrapper.Install.unzip(Install.java:214)
        at org.gradle.wrapper.Install.access$600(Install.java:27)
        at org.gradle.wrapper.Install$1.call(Install.java:74)
        at org.gradle.wrapper.Install$1.call(Install.java:48)
        at 
org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
        at org.gradle.wrapper.Install.createDist(Install.java:48)
        at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:128)
        at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
Gradle task assembleRelease failed with exit code 1

Error building Flet app - see the log of failed command above.

Any other ideas?

[deeplook]

Yes, I've used brew install --cask android-platform-tools and running sdkmanager --help gives a LinkageError:

java.lang.UnsupportedClassVersionError: com/android/sdklib/tool/sdkmanager/SdkManagerCli
has been compiled by a more recent version of the Java Runtime (class file version 61.0), this
version of the Java Runtime only recognizes class file versions up to 55.0

It seems like there are too many moving parts, versions and dependencies...

[09u2h4n]

It is caused by java which is i guess java version is 11 but 18 needed. Try to install java 18.

Maybe it helps to install:
https://thejavaguy.org/posts/001-how-to-install-jdk-18-on-macos/#:~:text=First%20you%20have%20to%20visit,because%20it's%20gzipped%20tar%20file.

Gradle/Java compatibility:

Java version	Support for compiling/testing/...	Support for running Gradle
8	N/A	2.0
9	N/A	4.3
10	N/A	4.7
11	N/A	5.0
12	N/A	5.4
13	N/A	6.0
14	N/A	6.3
15	6.7	6.7
16	7.0	7.0
17	7.3	7.3
18	7.5	7.5
19	7.6	7.6
20	8.1	8.3
21	8.4	8.5

[FeodorFitsner]

Look here: https://flet.dev/docs/guides/python/packaging-app-for-distribution#android - I've used temurin8 with SDK Manager and it worked pretty well.

[deeplook]

Which gives:

brew install --cask temurin8
==> Downloading https://formulae.brew.sh/api/cask.jws.json
#################################################################################### 100.0%
Warning: Cask 'temurin8' is unavailable: No Cask with this name exists.
==> Downloading https://formulae.brew.sh/api/formula.jws.json
#################################################################################### 100.0%
==> Searching for similarly named casks...
==> Casks
temurin

To install temurin, run:
  brew install --cask temurin

which would install jdk-21.0.2...

[jaluscgr]

I tried to do it on Linux but it didn't work for me even though it installed properly since I got a white screen. I found that on macOS in this way the apk could work:

     - export PATH="$PATH:$HOME/.local/bin"

       # Agregar el directorio bin de python3 al PATH
     - export PATH="$PATH:$(python3 -m site --user-base)/bin"

       # Añadir la clave GPG de Eclipse Adoptium
     - brew tap homebrew/cask-versions

     #instalar java 18
     - brew install --cask temurin18
     - export JAVA_HOME=$(/usr/libexec/java_home -v 18)
     
     - echo $JAVA_HOME

           
     
     #- brew install gradle
     ## Reinstall Gradle to Latest Version
     #- echo $"\nexport GRADLE_VERSION=$(echo $(arr=($(gradle --version | awk '{ print $2 }')) && echo ${arr[1]}))\n" >> /Users/$(whoami)/.zshrc
     #- echo $"\nexport GRADLE_HOME=`brew --prefix`/Cellar/gradle/$GRADLE_VERSION\n" >> /Users/$(whoami)/.zshrc
     #- echo $"\nexport PATH=$GRADLE_HOME/bin:$PATH\n" >> /Users/$(whoami)/.zshrc


     ## Since android-sdk is deprecated
     - brew install --cask android-commandlinetools

     # Export some paths
     - echo $"\nexport ANDROID_HOME=`brew --prefix`/share/android-commandlinetools\n" >> /Users/$(whoami)/.zshrc
     - echo $"\nexport PATH=$ANDROID_HOME:$PATH\n" >> /Users/$(whoami)/.zshrc

     - echo $"\nexport SDK_MANAGER=`brew --prefix`/bin/sdkmanager\n" >> /Users/$(whoami)/.zshrc
     - echo $"\nexport PATH=$SDK_MANAGER:$PATH\n" >> /Users/$(whoami)/.zshrc

     - echo $"\nexport AVD=`brew --prefix`/bin/avdmanager\n" >> /Users/$(whoami)/.zshrc
     - echo $"\nexport PATH=$AVD:$PATH\n" >> /Users/$(whoami)/.zshrc

     # Then Accept all licenses
     - yes | sdkmanager --licenses

     # Then Install Tools
     - y | sdkmanager "cmdline-tools;latest" "platforms;android-33" "emulator" "tools" "platform-tools" "ndk;25.2.9519653"


     - sdkmanager "ndk-bundle"


     - brew install android-platform-tools

     - echo $"\nexport ADB=`brew --prefix`/bin/adb\n" >> /Users/$(whoami)/.zshrc
     - echo $"\nexport PATH=$ADB:$PATH\n" >> /Users/$(whoami)/.zshrc


       # Instalar flet
     - pip3 install flet

     - export ANDROID_SDK_ROOT="/usr/local/share/android-commandlinetools"
     - export NDK_VERSION=25.2.9519653
     - export SDK_VERSION=android-33



     #- echo "y" | sdkmanager --install "ndk;$NDK_VERSION" --channel=3
     #- echo "y" | sdkmanager --install "platforms;$SDK_VERSION"     

     #- ls $ANDROID_HOME


       # Instalar python-for-android
     - pip3 install git+https://github.com/flet-dev/python-for-android.git@3.11.6

       # Actualizar Cython
     - pip3 install --upgrade cython


       # Crear el entorno de distribución para Python en Android
     - for i in {1..2}; do if [ $i -eq 1 ]; then echo "N"; else echo "Y"; fi; done | p4a create --requirements python3 --arch arm64-v8a --arch armeabi-v7a --arch x86_64 --sdk-dir $ANDROID_SDK_ROOT --ndk-dir $ANDROID_SDK_ROOT/ndk/$NDK_VERSION --dist-name mydist
     
     - export SERIOUS_PYTHON_P4A_DIST=$HOME/.python-for-android/dists/mydist



     
     #flutter
     - HOMEBREW_NO_AUTO_UPDATE=1 brew install cocoapods
     - curl $FLUTTER_MACOS_URL -o "$HOME/flutter_macos_stable.zip"
     - unzip -qq "$HOME/flutter_macos_stable.zip" -d $HOME
     - export PATH="$PATH:$HOME/flutter/bin"
     - flutter channel stable
     - flutter upgrade
     - flutter config --enable-macos-desktop
     - flutter doctor


  
    
     - flet build apk -vv