To date we have seen a small number of file formats for data, namely CSV and YAML. These are common and well suited to a range of simple applications. In Android we often use XML and Json. Here we review examples of all of these briefly.

In MyRent Lab 04 we incorporated a simple serialization mechanism to write Java objects to a Json file format. This required some significant enhancements to the models package, including a completely new Serializer class. Here we review these classes in detail.

Prior to API 23 it was sufficient to list the required permission in the manifest file. Beginning in Android 6.0 (API level 23) listing permissions in the manifest is necessary but no longer sufficient and users grant permissions to apps while the app is running, not when they install the app. Here we examine this rule change in the context of reading contacts in the MyRent app.

Activities within an application can reach out to activities in other applications to perform specific tasks. In this lab we introduce two new features - selecting a contact from the phone's contact lists, and sending an email to the selected user. Both of these features require the use of 'implicit' intents.

Supplementary MyRent lab to demonstrate how to request permissions at run time. We restrict ourselves to the single permission READ_CONTACTS.