Android-Activity, Intent, Service, Content Providers, Broadcast Receivers, Application context

Android life cycle

Running State, 看到的 Activity.

Pause State, activity 沒有被 focus, 這種情境是在彈跳視窗較常發生。

Stopped State, 看不到 Activity, 但還存在 Memory中。

Destroyed State, 看不到 Activity, 並且不存在 Memory中。

Intents

Intent，觸發資料溝通的元件之一。

Service life cycle

Service，背景作業，無使用者互動介面， Services and activities runs on the same main application thread, often called on UI thread.

Content provider

Content Providers，應用程式之閶資料交換的介面.

CRUD principle, Create, read, update and delete.

Contacts application using Contacts Provider to get the data

Broadcast Receivers, 發佈和訂閱的機制，Observer Pattern.

Application context, 上面加一加就是了；Context.getApplicationContext() or Activity.getApplication();

Activity life cycle state

onSaveInstanceState

onRestoreInstanceState

O'REILLY  Learning Android.

O'REILLY  Programming Android.