77.4 Declaring Request Codes

Working with files in the Storage Access Framework involves triggering a variety of intents depending on the specific action to be performed. Invariably this will result in the framework displaying the storage picker user interface so that the user can specify the storage location (such as a directory on Google Drive and the name of a file). When the work of the intent is complete, the application will be notified by a call to a method named onActivityResult().

Since all intents from a single activity will result in a call to the same onActivityResult() method, a mechanism is required to identify which intent triggered the call. This can be achieved by passing a request code through to the intent when it is launched. This code is then passed on to the onActivityResult() method by the intents, enabling the method to identify which action has been requested by the user. Before implementing the onClick handlers to create, save and open files, the first...