Our app works pretty well for saving pictures, but as soon as the app quits, all of the photos are lost. We need to add a way to save the photos permanently. Our refactoring of the code allows us to work primarily within the model layer now.
Before we write any code, we have to decide how we are going to store the photos permanently. There are many ways in which we can choose to save the photos, but one of the easiest is to save it to the file system, which is what we conceived of in our conception phase. Every app is provided a documents directory that is automatically backed up by the operating system as a part of normal backups. We can store our photos in there as files named after the label the user gives them. To avoid any problems with duplicate labels, where we would have multiple files named the same thing, we can nest every file inside a subdirectory named after the time the photos is saved. The time stamp will always be unique because we will never save...