Document PDF Convertor

I have a requirement for an application that will present the user with a list of their folders and contents. so when application open a list of folder on their phone will appear. Onclick or folder select a list of documents in that folder will appear. User should then be able to select from folder a file to convert to pdf. files types html jpg bmp word excel text The most important formats are html,text followed by word and excel. The file selected will be converted to pdf and placed in pdfConverted folder. The user should also have the option to mail the pdf file created from that folder. We will need the code and apk file when finished