Context and Activity

经常看到一些类中用到的context，从继承关系来看，activity就可以用。

public abstract class
Context
extends Object

java.lang.Object
↳	android.content.Context

Known Direct Subclasses ContextWrapper,  MockContext

Known Indirect Subclasses AbstractInputMethodService AbstractInputMethodService provides a abstract base class for input methods. AccessibilityService An accessibility service runs in the background and receives callbacks by the system when AccessibilityEvents are fired. AccountAuthenticatorActivity Base class for implementing an Activity that is used to help implement an AbstractAccountAuthenticator. Activity An activity is a single, focused thing that the user can do. ActivityGroup This class is deprecated. Use the new Fragment and FragmentManager APIs instead; these are also available on older platforms through the Android compatibility package.  AliasActivity Stub activity that launches another activity (and then finishes itself) based on information in its component’s manifest meta-data. Application Base class for those who need to maintain global application state. BackupAgent Provides the central interface between an application and Android’s data backup infrastructure. BackupAgentHelper A convenient BackupAgent wrapper class that automatically manages heterogeneous data sets within the backup data, each identified by a unique key prefix. ContextThemeWrapper A ContextWrapper that allows you to modify the theme from what is in the wrapped context. ExpandableListActivity An activity that displays an expandable list of items by binding to a data source implementing the ExpandableListAdapter, and exposes event handlers when the user selects an item. FragmentActivity Base class for activities that want to use the support-based Fragment and Loader APIs. InputMethodService InputMethodService provides a standard implementation of an InputMethod, which final implementations can derive from and customize. IntentService IntentService is a base class for Services that handle asynchronous requests (expressed as Intents) on demand. IsolatedContext A mock context which prevents its users from talking to the rest of the device while stubbing enough methods to satify code that tries to talk to other packages. LauncherActivity Displays a list of all activities which can be performed for a given intent. ListActivity An activity that displays a list of items by binding to a data source such as an array or Cursor, and exposes event handlers when the user selects an item. MockApplication A mock Application class. MutableContextWrapper Special version of ContextWrapper that allows the base context to be modified after it is initially set. NativeActivity Convenience for implementing an activity that will be implemented purely in native code. PreferenceActivity This is the base class for an activity to show a hierarchy of preferences to the user. RecognitionService This class provides a base class for recognition service implementations. RemoteViewsService The service to be connected to for a remote adapter to request RemoteViews. RenamingDelegatingContext This is a class which delegates to the given context, but performs database and file operations with a renamed database/file name (prefixes default names with a given prefix). Service A Service is an application component representing either an application’s desire to perform a longer-running operation while not interacting with the user or to supply functionality for other applications to use. SpellCheckerService SpellCheckerService provides an abstract base class for a spell checker. TabActivity This class is deprecated. New applications should use Fragments instead of this class; to continue to run on older devices, you can use the v4 support library which provides a version of the Fragment API that is compatible down to DONUT.  TextToSpeechService Abstract base class for TTS engine implementations. VpnService VpnService is a base class for applications to extend and build their own VPN solutions. WallpaperService A wallpaper service is responsible for showing a live wallpaper behind applications that would like to sit on top of it.

public class

Activity

extends ContextThemeWrapper
implements ComponentCallbacks2 KeyEvent.Callback LayoutInflater.Factory2 View.OnCreateContextMenuListener Window.Callback

java.lang.Object
↳	android.content.Context
	↳	android.content.ContextWrapper
		↳	android.view.ContextThemeWrapper
			↳	android.app.Activity

Known Direct Subclasses AccountAuthenticatorActivity,  ActivityGroup,  AliasActivity,  ExpandableListActivity,  FragmentActivity,  ListActivity,  NativeActivity

Known Indirect Subclasses LauncherActivity,  PreferenceActivity,  TabActivity

 Posted by ian at 00:13  Tagged with: Android