On the main BitPie wallet screen, click on the “Receive” button.
The QR code with your ROSE address will appear. Then, in the top right corner, tap on the kebab menu “⋮” and select “Display Private Key”.
BitPie wallet will now ask you to enter your PIN to access the private key.
Finally, your account’s private key will be shown to you encoded in Base64 format (e.g.
YgwGOfrHG1TVWSZBs8WM4w0BUjLmsbk7Gqgd7IGeHfSqdbeQokEhFEJxtc3kVQ4KqkdZTuD0bY7LOlhdEKevaQ==) which you can import into Oasis Wallet.