T
- The type of data obtained from the asset path (InputStream, FileDescriptor etc).public abstract class AssetPathFetcher<T> extends Object implements DataFetcher<T>
AssetManager
.Constructor and Description |
---|
AssetPathFetcher(AssetManager assetManager,
String assetPath) |
Modifier and Type | Method and Description |
---|---|
void |
cancel()
A method that will be called when a load is no longer relevant and has been cancelled.
|
void |
cleanup()
Cleanup or recycle any resources used by this data fetcher.
|
protected abstract void |
close(T data)
Closes the concrete data type if necessary.
|
String |
getId()
Returns a string uniquely identifying the data that this fetcher will fetch including the specific size.
|
T |
loadData(Priority priority)
Asynchronously fetch data from which a resource can be decoded.
|
protected abstract T |
loadResource(AssetManager assetManager,
String path)
Opens the given asset path with the given
AssetManager and returns the conrete data
type returned by the AssetManager. |
public AssetPathFetcher(AssetManager assetManager, String assetPath)
public T loadData(Priority priority) throws Exception
DataFetcher
ExecutorService
that may have more than one background thread.
This method will only be called when the corresponding resource is not in the cache.
Note - this method will be run on a background thread so blocking I/O is safe.
loadData
in interface DataFetcher<T>
priority
- The priority with which the request should be completed.Exception
where the data retuned will be cleaned up
public void cleanup()
DataFetcher
DataFetcher.loadData(Priority)
has been decoded by the
ResourceDecoder
.
Note - this method will be run on a background thread so blocking I/O is safe.
cleanup
in interface DataFetcher<T>
public String getId()
DataFetcher
A hash of the bytes of the data that will be fetched is the ideal id but since that is in many cases impractical, urls, file paths, and uris are normally sufficient.
Note - this method will be run on the main thread so it should not perform blocking operations and should finish quickly.
getId
in interface DataFetcher<T>
public void cancel()
DataFetcher
The best way to use this method is to cancel any loads that have not yet started, but allow those that are in process to finish since its we typically will want to display the same resource in a different view in the near future.
Note - this method will be run on the main thread so it should not perform blocking operations and should finish quickly.
cancel
in interface DataFetcher<T>
protected abstract T loadResource(AssetManager assetManager, String path) throws IOException
AssetManager
and returns the conrete data
type returned by the AssetManager.assetManager
- An AssetManager to use to open the given path.path
- A string path pointing to a resource in assets to open.IOException
protected abstract void close(T data) throws IOException
data
- The data to close.IOException