First Android App with Kotlin

Tutorial

tutorial: Build Your First Android App in Kotlin

features

• toast: by clicking this button, toast message shows, and then dismisses in seconds.
• count: by clicking this button, integer increases from 0 by 1.
• random: show random integer between 0 and counted number.
  • counted number updated by clicking the "count" button
  • by clicking the "random" button, next page will show a random integer between 0 and counted number
  • this counted number was passed through navigated pages via "androidx.navigation.safeargs"
• http: with retrofit2, by clicking count button, send request to httpbin.org
  • Android Networking With Kotlin Tutorial: Getting Started
  • Retrofit
  • httpbin.org

Screenshots

Development

build from command line

# list all tasks
./gradlew tasks

# build debug apk
./gradlew assemble

# apk path
ls -lh app/build/outputs/apk/debug

deploy to emulator

# ensure path in bash_profile/zshrc/...
# see https://stackoverflow.com/a/49511666/1448139
# e.g.:
export ANDROID_SDK=~/Library/Android/sdk
export PATH=${ANDROID_SDK}/emulator:${ANDROID_SDK}/tools:${ANDROID_SDK}/cmdline-tools/5.0/bin:${ANDROID_SDK}/platform-tools:$PATH

# list all emulators
emulator -list-avds

# start emulator
emulator -avd Pixel_5_API_30

# install use adb
adb install app/build/outputs/apk/debug/app-debug.apk

Issues

issue1: navigation-safe-args

• error: Type 'ArgumentsGenerationTask' property 'applicationId' is missing an input or output annotation.
• see: https://stackoverflow.com/a/67107330/1448139

issue2:

• error: Unresolved reference: SecondFragmentArgs
• see: google-developer-training/first-android-app#80

Reference

• Build your app from the command line
• Build Your First Android App in Kotlin
• GitHub Actions for Android developers
• Android Networking With Kotlin Tutorial: Getting Started
• Retrofit
• httpbin.org