lamacpp is kind of this. you give it a path to a model and a prompt. download a smallish model GGUF file by thebloke. lamacpp main exec has an interactive mode too which can function like a chatbot. i never built it on android though maybe you need android NDK
Do we have any llama apk/deb/flatpack/appimage where you just choose the llm to use?
Idk if GPT4All is what you want.
Do we have apt install gtp4qll?
https://gpt4all.io/index.html
Says ubuntu, works fine on my non-apt distro.
lamacpp is kind of this. you give it a path to a model and a prompt. download a smallish model GGUF file by thebloke. lamacpp main exec has an interactive mode too which can function like a chatbot. i never built it on android though maybe you need android NDK