java.lang.Object | |
↳ | android.support.v4.content.Loader<D> |
Known Direct Subclasses |
Known Indirect Subclasses |
Static library support version of the framework's Loader
.
Used to write apps that run on platforms prior to Android 3.0. When running
on Android 3.0 or above, this implementation is still used; it does not try
to switch to the framework's implementation. See the framework SDK
documentation for a class overview.
Nested Classes | |||||||||||
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Loader.ForceLoadContentObserver | An implementation of a ContentObserver that takes care of connecting it to the Loader to have the loader re-load its data when the observer is told it has changed. | ||||||||||
Loader.OnLoadCompleteListener<D> | Interface that is implemented to discover when a Loader has finished loading its data. |
Public Constructors | |||||||||||
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Stores away the application context associated with context.
|
Public Methods | |||||||||||
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Tell the Loader that it is being abandoned.
| |||||||||||
For debugging, converts an instance of the Loader's data class to
a string that can be printed.
| |||||||||||
Sends the result of the load to the registered listener.
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Print the Loader's state into the given stream.
| |||||||||||
Force an asynchronous load.
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Return whether this loader has been abandoned.
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Return whether this load has been reset.
| |||||||||||
Return whether this load has been started.
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Called when
Loader.ForceLoadContentObserver detects a change. | |||||||||||
Registers a class that will receive callbacks when a load is complete.
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Resets the state of the Loader.
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Starts an asynchronous load of the Loader's data.
| |||||||||||
Stops delivery of updates until the next time
startLoading() is called. | |||||||||||
Take the current flag indicating whether the loader's content had
changed while it was stopped.
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Returns a string containing a concise, human-readable description of this
object.
| |||||||||||
Remove a listener that was previously added with
registerListener(int, Loader.OnLoadCompleteListener . |
Protected Methods | |||||||||||
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Subclasses implement this to take care of being abandoned.
| |||||||||||
Subclasses must implement this to take care of requests to
forceLoad() . | |||||||||||
Subclasses must implement this to take care of resetting their loader,
as per
reset() . | |||||||||||
Subclasses must implement this to take care of loading their data,
as per
startLoading() . | |||||||||||
Subclasses must implement this to take care of stopping their loader,
as per
stopLoading() . |
[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
|
Stores away the application context associated with context. Since Loaders can be used across multiple activities it's dangerous to store the context directly.
context | used to retrieve the application context. |
---|
Tell the Loader that it is being abandoned. This is called prior
to reset()
to have it retain its current data but not report
any new data.
For debugging, converts an instance of the Loader's data class to a string that can be printed. Must handle a null data.
Sends the result of the load to the registered listener. Should only be called by subclasses. Must be called from the process's main thread.
data | the result of the load |
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Print the Loader's state into the given stream.
prefix | Text to print at the front of each line. |
---|---|
fd | The raw file descriptor that the dump is being sent to. |
writer | A PrintWriter to which the dump is to be set. |
args | Additional arguments to the dump request. |
Force an asynchronous load. Unlike startLoading()
this will ignore a previously
loaded data set and load a new one. This simply calls through to the
implementation's onForceLoad()
. You generally should only call this
when the loader is started -- that is, isStarted()
returns true.
Must be called from the process's main thread.
Return whether this loader has been abandoned. In this state, the loader must not report any new data, and must keep its last reported data valid until it is finally reset.
Return whether this load has been reset. That is, either the loader
has not yet been started for the first time, or its reset()
has been called.
Return whether this load has been started. That is, its startLoading()
has been called and no calls to stopLoading()
or
reset()
have yet been made.
Called when Loader.ForceLoadContentObserver
detects a change. The
default implementation checks to see if the loader is currently started;
if so, it simply calls forceLoad()
; otherwise, it sets a flag
so that takeContentChanged()
returns true.
Must be called from the process's main thread.
Registers a class that will receive callbacks when a load is complete. The callback will be called on the process's main thread so it's safe to pass the results to widgets.
Must be called from the process's main thread.
Resets the state of the Loader. The Loader should at this point free
all of its resources, since it may never be called again; however, its
startLoading()
may later be called at which point it must be
able to start running again.
This updates the Loader's internal state so that
isStarted()
and isReset()
will return the correct
values, and then calls the implementation's onReset()
.
Must be called from the process's main thread.
Starts an asynchronous load of the Loader's data. When the result
is ready the callbacks will be called on the process's main thread.
If a previous load has been completed and is still valid
the result may be passed to the callbacks immediately.
The loader will monitor the source of
the data set and may deliver future callbacks if the source changes.
Calling stopLoading()
will stop the delivery of callbacks.
This updates the Loader's internal state so that
isStarted()
and isReset()
will return the correct
values, and then calls the implementation's onStartLoading()
.
Must be called from the process's main thread.
Stops delivery of updates until the next time startLoading()
is called.
Implementations should not invalidate their data at this point --
clients are still free to use the last data the loader reported. They will,
however, typically stop reporting new data if the data changes; they can
still monitor for changes, but must not report them to the client until and
if startLoading()
is later called.
This updates the Loader's internal state so that
isStarted()
will return the correct
value, and then calls the implementation's onStopLoading()
.
Must be called from the process's main thread.
Take the current flag indicating whether the loader's content had changed while it was stopped. If it had, true is returned and the flag is cleared.
Returns a string containing a concise, human-readable description of this object. Subclasses are encouraged to override this method and provide an implementation that takes into account the object's type and data. The default implementation is equivalent to the following expression:
getClass().getName() + '@' + Integer.toHexString(hashCode())
See Writing a useful
toString
method
if you intend implementing your own toString
method.
Remove a listener that was previously added with registerListener(int, Loader.OnLoadCompleteListener
.
Must be called from the process's main thread.
Subclasses implement this to take care of being abandoned. This is
an optional intermediate state prior to onReset()
-- it means that
the client is no longer interested in any new data from the loader,
so the loader must not report any further updates. However, the
loader must keep its last reported data valid until the final
onReset()
happens. You can retrieve the current abandoned
state with isAbandoned()
.
Subclasses must implement this to take care of requests to forceLoad()
.
This will always be called from the process's main thread.
Subclasses must implement this to take care of loading their data,
as per startLoading()
. This is not called by clients directly,
but as a result of a call to startLoading()
.
Subclasses must implement this to take care of stopping their loader,
as per stopLoading()
. This is not called by clients directly,
but as a result of a call to stopLoading()
.
This will always be called from the process's main thread.