ContentObserver
public
abstract
class
ContentObserver
extends Object
java.lang.Object | |
↳ | android.database.ContentObserver |
Receives call backs for changes to content.
Must be implemented by objects which are added to a ContentObservable
.
Summary
Public constructors | |
---|---|
ContentObserver(Handler handler)
Creates a content observer. |
Public methods | |
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boolean
|
deliverSelfNotifications()
Returns true if this observer is interested receiving self-change notifications. |
final
void
|
dispatchChange(boolean selfChange)
This method was deprecated
in API level 16.
Callers should migrate towards using a richer overload that
provides more details about the change, such as
|
final
void
|
dispatchChange(boolean selfChange, Uri uri)
Dispatches a change notification to the observer. |
final
void
|
dispatchChange(boolean selfChange, Uri uri, int flags)
Dispatches a change notification to the observer. |
final
void
|
dispatchChange(boolean selfChange, Collection<Uri> uris, int flags)
Dispatches a change notification to the observer. |
void
|
onChange(boolean selfChange, Uri uri, int flags)
This method is called when a content change occurs. |
void
|
onChange(boolean selfChange)
This method is called when a content change occurs. |
void
|
onChange(boolean selfChange, Uri uri)
This method is called when a content change occurs. |
void
|
onChange(boolean selfChange, Collection<Uri> uris, int flags)
This method is called when a content change occurs. |
Inherited methods | |
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Public constructors
ContentObserver
public ContentObserver (Handler handler)
Creates a content observer.
Parameters | |
---|---|
handler |
Handler : The handler to run onChange(boolean) on, or null if none. |
Public methods
deliverSelfNotifications
public boolean deliverSelfNotifications ()
Returns true if this observer is interested receiving self-change notifications. Subclasses should override this method to indicate whether the observer is interested in receiving notifications for changes that it made to the content itself.
Returns | |
---|---|
boolean |
True if self-change notifications should be delivered to the observer. |
dispatchChange
public final void dispatchChange (boolean selfChange)
This method was deprecated
in API level 16.
Callers should migrate towards using a richer overload that
provides more details about the change, such as
dispatchChange(boolean, java.util.Collection, int)
.
Dispatches a change notification to the observer.
If a Handler
was supplied to the ContentObserver
constructor, then a call to the onChange(boolean)
method is posted to the
handler's message queue. Otherwise, the onChange(boolean)
method is
invoked immediately on this thread.
Parameters | |
---|---|
selfChange |
boolean |
dispatchChange
public final void dispatchChange (boolean selfChange, Uri uri)
Dispatches a change notification to the observer. Includes the changed content Uri when available.
If a Handler
was supplied to the ContentObserver
constructor, then a call to the onChange(boolean)
method is posted to the
handler's message queue. Otherwise, the onChange(boolean)
method is
invoked immediately on this thread.
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
uri |
Uri : The Uri of the changed content.
This value may be null . |
dispatchChange
public final void dispatchChange (boolean selfChange, Uri uri, int flags)
Dispatches a change notification to the observer. Includes the changed content Uri when available.
If a Handler
was supplied to the ContentObserver
constructor, then a call to the onChange(boolean)
method is posted to the
handler's message queue. Otherwise, the onChange(boolean)
method is
invoked immediately on this thread.
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
uri |
Uri : The Uri of the changed content.
This value may be null . |
flags |
int : Flags indicating details about this change.
Value is either 0 or a combination of ContentResolver.NOTIFY_SYNC_TO_NETWORK , ContentResolver.NOTIFY_SKIP_NOTIFY_FOR_DESCENDANTS , ContentResolver.NOTIFY_INSERT , ContentResolver.NOTIFY_UPDATE , and ContentResolver.NOTIFY_DELETE |
dispatchChange
public final void dispatchChange (boolean selfChange, Collection<Uri> uris, int flags)
Dispatches a change notification to the observer. Includes the changed content Uris when available.
If a Handler
was supplied to the ContentObserver
constructor, then a call to the onChange(boolean)
method is posted to the
handler's message queue. Otherwise, the onChange(boolean)
method is
invoked immediately on this thread.
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
uris |
Collection : The Uri of the changed content.
This value cannot be null . |
flags |
int : Flags indicating details about this change.
Value is either 0 or a combination of ContentResolver.NOTIFY_SYNC_TO_NETWORK , ContentResolver.NOTIFY_SKIP_NOTIFY_FOR_DESCENDANTS , ContentResolver.NOTIFY_INSERT , ContentResolver.NOTIFY_UPDATE , and ContentResolver.NOTIFY_DELETE |
onChange
public void onChange (boolean selfChange, Uri uri, int flags)
This method is called when a content change occurs. Includes the changed content Uri when available.
Subclasses should override this method to handle content changes. To ensure correct operation on older versions of the framework that did not provide richer arguments, applications should implement all overloads.
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
uri |
Uri : The Uri of the changed content.
This value may be null . |
flags |
int : Flags indicating details about this change.
Value is either 0 or a combination of ContentResolver.NOTIFY_SYNC_TO_NETWORK , ContentResolver.NOTIFY_SKIP_NOTIFY_FOR_DESCENDANTS , ContentResolver.NOTIFY_INSERT , ContentResolver.NOTIFY_UPDATE , and ContentResolver.NOTIFY_DELETE |
onChange
public void onChange (boolean selfChange)
This method is called when a content change occurs.
Subclasses should override this method to handle content changes.
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
onChange
public void onChange (boolean selfChange, Uri uri)
This method is called when a content change occurs. Includes the changed content Uri when available.
Subclasses should override this method to handle content changes. To ensure correct operation on older versions of the framework that did not provide richer arguments, applications should implement all overloads.
Example implementation:
// Implement the onChange(boolean) method to delegate the change notification to
// the onChange(boolean, Uri) method to ensure correct operation on older versions
// of the framework that did not have the onChange(boolean, Uri) method.
@Override
public void onChange(boolean selfChange) {
onChange(selfChange, null);
}
// Implement the onChange(boolean, Uri) method to take advantage of the new Uri argument.
@Override
public void onChange(boolean selfChange, Uri uri) {
// Handle change.
}
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
uri |
Uri : The Uri of the changed content.
This value may be null . |
onChange
public void onChange (boolean selfChange, Collection<Uri> uris, int flags)
This method is called when a content change occurs. Includes the changed content Uris when available.
Subclasses should override this method to handle content changes. To ensure correct operation on older versions of the framework that did not provide richer arguments, applications should implement all overloads.
Parameters | |
---|---|
selfChange |
boolean : True if this is a self-change notification. |
uris |
Collection : The Uris of the changed content.
This value cannot be null . |
flags |
int : Flags indicating details about this change.
Value is either 0 or a combination of ContentResolver.NOTIFY_SYNC_TO_NETWORK , ContentResolver.NOTIFY_SKIP_NOTIFY_FOR_DESCENDANTS , ContentResolver.NOTIFY_INSERT , ContentResolver.NOTIFY_UPDATE , and ContentResolver.NOTIFY_DELETE |