Write an Android application

Make a notebook apps on Android. What I am thinking in my head is the Note in Mac. The apps would allow people to write plain text files. No need to consider file names or so. I want everything simple and fast. Just use random GUIDs as file names. In the interface, show the first line of a file content, so users can tell which file it is would be good enough. The interface doesn't matter. Just a simple interface that cost the least time to implement would be good. A tricky part is: the app would sync the text files to the cloud, like Dropbox. I would accept OneDrive or Google Drive too. Perhaps Google Drive make sense for it is native to Android. Just choose one cloud service that is fastest and easiest to implement. Don't bother to implement and test on more than one cloud. The developer should propose which cloud to use. The most tricky part is: the apps would accept a password, and encrypt the content of the files before syncing to the cloud. It is OK to store plain text locally; however, when sync to cloud, it must be encrypted. The developer should propose which encryption algorithm to use. I would accept to store the password in plain text locally if it would help the initial release faster. We can assume a user who uses such apps would encrypt his phone's memory. However, please do reserve flexibility to store the password in a better way. We may want to improve it in the future. The sync would be one-way sync. That is: from the only one Android device to the cloud. No need to consider multiple Android devices to sync to the same cloud. Considering it is interesting but would incur very high development cost.