data and persistence

In this assignment, you will add the data structures to hold the messages and the contacts and fill in more of the actual behavior of the activities. 1) Create a message data structure that contains a) the sender's username b) the subject line c) the message body d) the time to delete the message 2) Create the contact data structure that contains a) the username b) the user image c) the public key 3) On initial startup (just the first time the app is installed). All of this information should be persisted so that it will remain (subject to time-to-live restrictions). The key pair can remain in SharedPreferences, but the messages and contacts should be placed in an SQLite database. a) Create a KeyPair b) Generate three fake messages i) Each with distinct sender/subject combinations ii) The time-to-live of one message should be five seconds. iii) The time-to-live of the second should be fifteen seconds. iv) The time-to-live of the third should be five minutes. c) Generate three fake contacts 4) Clicking on an item in the list on the main activity should open the 'Read' activity with sender, subject, etc. related to the selected message. a) clicking the delete button should return to the main activity and the associated message should be removed from the list. b) clicking the reply button will load the compose message with the "To:" line filled in. 5) On the compose activity a) if the user hits send, just put up a toast with the encrypted message. 6) On the contact panel a) clicking a contact will load the compose activity with the 'To:' line filled in. b) clicking the '+' icon will result in the contact field with empty information i) If the name field is filled (with anything) and the search button is pressed, the picture and public key will be populated with fake data (the same image can be used for all, but generate a new key each time). ii) If the save button is pressed the new contact will be added to the contacts list. c) Clicking on the 'edit' icon will open a contact page with the 'save' button greyed out (only useful for deleting contacts) i) clicking the 'delete' icon will result in the contact being removed from the contacts list.