automate ndk install in doctor script

[mikehardy]

• doctor can do a better job of installing ndk, I've automated that in other places

Originally posted by @mikehardy in #194 (comment)

NDK automation example:

# check Android NDK is installed, if not release APK is bigger because there is no strip tool
ANDROID_NDK_WANTED=$(grep ndkVersion < packages/public-app/android/build.gradle | cut -d"'" -f2)
echo "Verifying Android NDK (want version $ANDROID_NDK_WANTED)"  
if ! ls -1 "$ANDROID_SDK_ROOT/ndk/$ANDROID_NDK_WANTED/package.xml" >/dev/null 2>&1; then
  echo "Android NDK not installed or not correct version (got $ANDROID_NDK). Installing NDK $ANDROID_NDK_WANTED"
  echo 'count=0' > ~/.android/repositories.cfg
  if ! echo y | "$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager" --no_https "ndk;$ANDROID_NDK_WANTED"; then
    echo "Installing Android NDK failed?"
    exit 1
  fi
fi

relies on cmdline-tools latest being installed which is not always the case, here's that:

# Verify apkanalyzer (used for Android release build script) works after Java11 update
echo "Verifying Android command-line tools are up to date and in PATH"
if ! apkanalyzer > /dev/null 2>&1; then
  echo "Android command-line tools not set up correctly, fixing..."
  if ! [ -f "$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/apkanalyzer" ]; then
    echo "Android development has updated to Java 11, but your command-line tools don't support it."
    echo "You need to open Android Studio, start the SDK Manager tool, install command-line tools, re-run doctor"
    exit 1
  fi
  echo "export PATH=\"\$ANDROID_SDK_ROOT/cmdline-tools/latest/bin:\$PATH\"" >> "$HOME/.bash_profile"
fi

which in turn relies on ANDROID_SDK_ROOT,

# Check Android Studio status optionally?
echo "Verifying Android SDK installation"
if [ "$ANDROID_SDK_ROOT" == "" ]; then
  echo "ANDROID_SDK_ROOT environment variable not found. Configuring standard location"
  USER=$(whoami)
  if [ "$(uname)" == "Darwin" ]; then
    export ANDROID_SDK_ROOT="/Users/$USER/Library/Android/sdk"
  else
    export ANDROID_SDK_ROOT="/home/$USER/Android/Sdk"
  fi
  if ! [ -d "$ANDROID_SDK_ROOT/" ]; then
    echo "Configuring ANDROID_SDK_ROOT to standard location $ANDROID_SDK_ROOT failed"
    exit 1
  else
    echo "export ANDROID_SDK_ROOT=\"$ANDROID_SDK_ROOT\"" >> "$HOME/.bash_profile"
    echo "export PATH=\"\$ANDROID_SDK_ROOT/emulator:\$ANDROID_SDK_ROOT/platform-tools:\$ANDROID_SDK_ROOT/cmdline-tools/latest/bin:\$ANDROID_SDK_ROOT
/tools:\$PATH\"" >> "$HOME/.bash_profile"
    echo "Standard ANDROID_SDK_ROOT location found. Auto-configuration successful."
    echo "!!! You will need to start a new Terminal session before Android builds work."
  fi
fi