Unit 01 of 02
Application Components
Android architecture layers from the kernel to the application framework, activities and their lifecycles, fragments, services, broadcast receivers, content providers, explicit and implicit intents with intent filters, and tasks and the back stack.
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Lessons
- 01 Android Architecture Layers Measures whether a request an app makes to the platform is fulfilled as full, substitute, pending, or unmet, and how that request passes through the layers from the Linux kernel to the application framework. 14 min read
- 02 Activities Measures what an activity is, how it is declared in the manifest file, and how the platform fulfills a request for an activity that is undeclared or closed to other apps. 13 min read
- 03 The Activity Lifecycle Measures the lifecycle callbacks of an activity, which state survives a configuration change and process death, and how a UI request that reaches a stopped activity is fulfilled. 12 min read
- 04 Fragments Measures where a fragment sits inside an activity, how FragmentManager transactions work, and how a fragment transaction is fulfilled while the host activity is stopped or has already saved its state. 11 min read
- 05 Services Measures the difference between started, bound, and foreground services, that a service is not a thread, and how the platform fulfills a request to start a service from the background. 13 min read
- 06 Broadcast Receivers Measures how a broadcast receiver is registered in the manifest file and at run time, that an implicit system broadcast does not reach a declared receiver, and that the same receiver class gets different fulfillments by three paths. 13 min read
- 07 Content Providers How a content provider resolves a content URI with a URI matcher, how an unknown path, a missing row and a missing column are fulfilled, and why a query without permission stays unmet. 12 min read
- 08 Intents and Intent Filters The difference between an explicit and an implicit intent, how an intent filter matches on action, category and data, the pending fulfillment when more than one app fulfills the same intent, and the result that changes when the default app is removed. 12 min read
- 09 Tasks and the Back Stack The structure of the task and the back stack, whether the launch modes use a new instance or the existing one, how the same mode gets two different fulfillments depending on the state of the stack, and the edge case of the CLEAR_TOP flag. 13 min read