use file_to_dropbox_from_bitbucket

bitbucket-pipelines.yml

image: uber/android-build-environment:latest

pipelines:
  branches:
    master:
      - step:
          script:
              - mkdir -p "$ANDROID_HOME/licenses"
              - echo -e "\n8933bad161af4178b1185d1a37fbf41ea5269c55" >> "$ANDROID_HOME/licenses/android-sdk-license"
              - echo -e "d56f5187479451eabf01fb78af6dfcb131a6481e" >> "$ANDROID_HOME/licenses/android-sdk-license"
              - echo -e "\nd975f751698a77b662f1254ddbeed3901e976f5a" >> "$ANDROID_HOME/licenses/intel-android-extra-license"
              - echo y | android update sdk --no-ui -a
              - bash gradlew clean assembleRelease
              - bash dropbox.sh

dropbox.sh

#!/bin/bash

curl -X POST https://api.dropboxapi.com/2/files/delete \
    --header 'Authorization: Bearer ${access_token}' \
    --header 'Content-Type: application/json' \
    --data '{"path":"/module/${apk-name}.apk"}'

curl -X POST https://content.dropboxapi.com/2/files/upload \
    --header "Authorization: Bearer ${access_token}" \
    --header "Dropbox-API-Arg: { \"path\": \"/module/${apk-name}.apk\", \"mode\": \"add\", \"autorename\": true, \"mute\": false }" \
    --header "Content-Type: application/octet-stream" \
    --data-binary @app/build/outputs/apk/release/app-release.apk