- Bitcoin Wallet (Android)
1) Download OpenSSL for your operation system
2) You have to make the make the backup of your wallet (on the android app), by choosing a password and then by moving the backup file on your computer.
3) Then put the backup file in the same folder where there is the executable of OpenSSL
4) Start the command line from the folder and execute this: openssl enc -d -aes-256-cbc -a -in backup_file > result.txt
5) Open result.txt. You will find much incomprehensible text, but at the beginning, there will be a list of 12 words. Save them somewhere. It is the seed.
6) Download and execute this: https://github.com/iancoleman/bip39/blob/master/bip39-standalone.html (Right click and Save as...)
7) On "BIP39 Mnemonic" space you have to insert the seed of your wallet, the 12 words.
8 ) In "Derivation Path" choose "BIP32"
9) On "Client" choose "Multibit HD"
10) You will get the list of your addresses and their private keys.
11) Sweep them with Coinomi

Update
- you can recover the seed from v3.47 or upper with https://github.com/gurnec/decrypt_bitcoinj_seed
- Some BCH could be on the private keys on son address with those settings on the bip39-standalone.html page
Client: Custom derivation path:
BIP32 Derivation Path: m/0'/1