Installation

Install NDK on Linux (not recommmended)

(Use the following SDK to install NDK)

See https://developer.android.com/ndk/downloads/index.html

See https://www.cryptopp.com/wiki/Android_Setup_(Command_Line) for details.

wget https://dl.google.com/android/repository/android-ndk-r25-linux.zip
unzip -d /ceph-fj/fangjun/software android-ndk-r25-linux.zip
# It will create /ceph-fj/fangjun/software/android-ndk-r25

Other versions can be downloaded from https://github.com/android/ndk/wiki/Unsupported-Downloads

wget https://dl.google.com/android/repository/android-ndk-r24-linux.zip
unzip -d /ceph-fj/fangjun/software android-ndk-r24-linux.zip

# It will create /ceph-fj/fangjun/software/android-ndk-r24

Now create a symlink in /ceph-fj/fangjun/software:

cd /ceph-fj/fangjun/software
ln -s android-ndk-r25 android-ndk

Set the following environment variable:

export ANDROID_NDK_ROOT=/ceph-fj/fangjun/software/android-ndk
export PATH=$ANDROID_NDK_ROOT:$PATH

Install SDK on Linux

Download the commandline tools only from https://developer.android.com/studio#downloads

wget https://dl.google.com/android/repository/commandlinetools-linux-8512546_latest.zip
unzip -d /ceph-fj/fangjun/software/android-sdk ./commandlinetools-linux-8512546_latest.zip
# Everything is inside /ceph-fj/fangjun/software/android-sdk/cmdline-tools/
cd /ceph-fj/fangjun/software/android-sdk
mv cmdline-tools latest
mkdir cmdline-tools
mv latest ./cmdline-tools/

If we don't run mv cmdline-tools latest, it will throw the following error

$ /ceph-fj/fangjun/software/android-sdk/cmdline-tools/bin/sdkmanager --list

Error: Could not determine SDK root.
Error: Either specify it explicitly with --sdk_root= or move this package into its expected location: <sdk>/cmdline-tools/latest/

sdkmanager --update
sdkmanager --list

# Install the build tools
sdkmanager "platforms;android-28" "build-tools;28.0.3"
# It will create the following directories inside /ceph-fj/fangjun/software/android-sdk/
#
# build-tools, emulator, licenses, patcher, platform-tools, platforms, tools

$ sdkmanager --list_installed
Installed packages:=====================] 100% Fetch remote repository...
  Path                 | Version | Description                    | Location
  -------              | ------- | -------                        | -------
  build-tools;28.0.3   | 28.0.3  | Android SDK Build-Tools 28.0.3 | build-tools/28.0.3
  emulator             | 31.3.10 | Android Emulator               | emulator
  patcher;v4           | 1       | SDK Patch Applier v4           | patcher/v4
  platform-tools       | 33.0.2  | Android SDK Platform-Tools     | platform-tools
  platforms;android-28 | 6       | Android SDK Platform 28        | platforms/android-28

sdkmanager --help
yes | sdkmanager --licenses  # to accept or licenses, the decision is saved in a cache file.

Set the following environment variables:

export ANDROID_SDK_ROOT=/ceph-fj/fangjun/software/android-sdk
export PATH=$ANDROID_SDK_ROOT/cmdline-tools/latest/bin:$PATH

export ANDROID_HOME=/ceph-fj/fangjun/software/android-sdk

# for emulator
export PATH=$ANDROID_SDK_ROOT/emulator:$PATH

# for adb
export PATH=$ANDROID_SDK_ROOT/platform-tools:$PATH

# We installed 28.0.3 before
export PATH=$ANDROID_SDK_ROOT/build-tools/28.0.3:$PATH # change it for different versions

Now install NDK using sdkmanager:

# sdkmanager --list | grep ndk
sdkmanager "ndk;21.0.6113669"
# it will download android-ndk-r21 and will generate
#  android-sdk/ndk/21.0.6113669

export ANROID_NDK_HOME=$ANDROID_SDK_ROOT/ndk/21.0.6113669
export PATH=$ANDROID_NDK_ROOT:$PATH

emulator

find /Users/fangjun/software/my-android -name emulator
/Users/fangjun/software/my-android/emulator -list-avds
/Users/fangjun/software/my-android/emulator -avd Pixel_4_API_31 -dns-server 8.8.8.8

Refer to https://developer.android.com/studio/run/emulator-networking#proxy to setup the proxy.