Add audio to text project

I have an application that shows instruction texts. I want to add audio as well. Right now I use sherlookactionbar, so the audio play button will be displayed on that bar. The way it works is as follows: Each instruction has a main ID number. When the user clicks on PLAY, the button changes to PAUSE and if held will STOP playing. Also, user can press the SETTINGS button (on the bar already) and it will continue to play. After the user presses the PLAY, the application should check if file is stored locally. If it is, then just play, otherwise, download from [login to view URL] and store it locally for later (example: /sdcard/Android/data/[login to view URL]). You should take care of the following things: Check if there is enough space to download the file (files are relatively small - no more than 3 MB each) Start downloading the file to a temporary location and only once finished move it to correct folder and make sure you clean temporary file every time in case something happens Take care of any exceptions, such as No Internet Connection and display appropriate message Take care of lost of network connection or user interruptions Only display PAUSE when it starts playing, not downloading Display appropriate messages, such as DOWNLOAD PROGRESS… DOWNLOAD COMPLETE for ID … etc Switching to landscape mode and back should not interrupt the play in any way, however, going to main menu or closing the app will stop Add a preference option to DOWNLOAD ALL where it shows downloaded IDs/total IDs (a progress bar) where the total IDs is a static final number. When pressing DOWNLOAD ALL: should ONLY download those that are not already in the media folder (downloaded) and will do it one file at a time showing progress and displaying appropriate messages. Assume there are a total of 900 MP3 files and the total memory required will be around 1 GB (you should check this as well). Display a confirmation message after pressing DOWNLOAD ALL that states "1 GB required and WIFI connection. Are you sure?" with the buttons YES and CANCEL. Also, add an button to delete all MP3s. Display a confirmation message and if yes is clicked, delete every mp3 file (empty media folder). Lastly, as a security measure, the application should obfuscate the file ID. Example: if the ID to PLAY is 23, obfuscate the file ID to something like [login to view URL] or [login to view URL] (file on server will be not obfuscated, just regular [login to view URL]) The only two permissions allowed are NETWORK CONNECTION (INTERNET) and SDCARD ACCESS. I'm open to comments and suggestions.