NetworkFetcher
| com.facebook.imagepipeline.producers.NetworkFetcher<FETCH_STATE extends com.facebook.imagepipeline.producers.FetchState> |
 Known Indirect Subclasses
BaseNetworkFetcher<FETCH_STATE extends FetchState>,
HttpUrlConnectionNetworkFetcher,
OkHttpNetworkFetcher,
PriorityNetworkFetcher<FETCH_STATE extends FetchState>,
VolleyNetworkFetcher
|
Class Overview
Interface that specifies network fetcher used by the image pipeline.
It is strongly recommended that implementations use an Executor in their fetch(FETCH_STATE, NetworkFetcher.Callback) method to execute the network request on a different thread.
When the fetch from the network fails or is cancelled, the subclass is responsible for calling
NetworkFetcher.Callback methods. If these are not called, the pipeline will not know that the image
fetch has failed and the application may not behave properly.
Summary
| Nested Classes | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| interface | NetworkFetcher.Callback | Callback used to inform the network fetch producer. | |||||||||
| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| abstract FETCH_STATE |
createFetchState(Consumer<EncodedImage> consumer, ProducerContext producerContext)
Creates a new instance of the
FetchState-derived object used to store state. | ||||||||||
| abstract void |
fetch(FETCH_STATE fetchState, NetworkFetcher.Callback callback)
Initiates the network fetch and informs the producer when a response is received via the
provided callback.
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| abstract Map<String, String> |
getExtraMap(FETCH_STATE fetchState, int byteSize)
Gets a map containing extra parameters to pass to the listeners.
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| abstract void |
onFetchCompletion(FETCH_STATE fetchState, int byteSize)
Called after the fetch completes.
| ||||||||||
| abstract boolean |
shouldPropagate(FETCH_STATE fetchState)
Gets whether the intermediate results should be propagated.
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Public Methods
public abstract FETCH_STATE createFetchState (Consumer<EncodedImage> consumer, ProducerContext producerContext)
Creates a new instance of the FetchState-derived object used to store state.
Parameters
| consumer | the consumer |
|---|---|
| producerContext | the producer's context |
Returns
- a new fetch state instance
public abstract void fetch (FETCH_STATE fetchState, NetworkFetcher.Callback callback)
Initiates the network fetch and informs the producer when a response is received via the provided callback.
Parameters
| fetchState | the fetch-specific state |
|---|---|
| callback | the callback used to inform the network fetch producer |
public abstract Map<String, String> getExtraMap (FETCH_STATE fetchState, int byteSize)
Gets a map containing extra parameters to pass to the listeners.
Returning map is optional and is useful for instrumentation purposes.
This map won't be modified by the caller.
Parameters
| fetchState | the fetch-specific state |
|---|---|
| byteSize | size of the data in bytes |
Returns
- a map with extra parameters
public abstract void onFetchCompletion (FETCH_STATE fetchState, int byteSize)
Called after the fetch completes.
Implementing this method is optional and is useful for instrumentation purposes.
Parameters
| fetchState | the fetch-specific state |
|---|---|
| byteSize | size of the data in bytes |
public abstract boolean shouldPropagate (FETCH_STATE fetchState)
Gets whether the intermediate results should be propagated.
In addition to the requirements of this method, intermediate results are throttled so that a maximum of one every 100 ms is propagated. This is to conserve CPU and other resources.
Not applicable if progressive rendering is disabled or not supported for this image.
Parameters
| fetchState | the fetch-specific state |
|---|
Returns
- whether the intermediate results should be propagated