public
abstract
class
ContentObserver
extends Object
| java.lang.Object | |
| ↳ | android.database.ContentObserver |
 Known Direct Subclasses
|
Receives call backs for changes to content.
Must be implemented by objects which are added to a ContentObservable.
Public constructors | |
|---|---|
ContentObserver(Handler handler)
Creates a content observer. |
|
Public methods | |
|---|---|
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.
Use |
final
void
|
dispatchChange(boolean selfChange, Uri uri)
Dispatches a change notification to the observer. |
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. |
Inherited methods | |
|---|---|
From
class
java.lang.Object
| |
ContentObserver (Handler handler)
Creates a content observer.
| Parameters | |
|---|---|
handler |
Handler:
The handler to run onChange(boolean) on, or null if none.
|
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. |
void dispatchChange (boolean selfChange)
This method was deprecated
in API level 16.
Use dispatchChange(boolean, Uri) instead.
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:
True if this is a self-change notification. |
Developers
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, or null if unknown.
|
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.
|
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 a Uri argument, applications should also implement
the onChange(boolean) overload of this method whenever they
implement the onChange(boolean, Uri) overload.
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, or null if unknown.
|