51.7 Summary

Intents are the messaging mechanism by which one Android activity can launch another. An explicit intent references a specific activity to be launched by referencing the receiving activity by class name. Explicit intents are typically, though not exclusively, used when launching activities contained within the same application. An implicit intent specifies the action to be performed and the type of data to be handled, and lets the Android runtime find a matching activity to launch. Implicit intents are generally used when launching activities that reside in different applications.

An activity can send data to the receiving activity by bundling data into the intent object in the form of key-value pairs. Data can only be returned from an activity if it is started as a sub-activity of the sending activity.

Activities advertise capabilities to the Android intent resolution process through the specification of intent-filters in the application manifest file. Both sending...