com.scvngr.levelup.core.ui.view

Class LevelUpCodeLoader

java.lang.Object

com.scvngr.levelup.core.ui.view.LevelUpCodeLoader

All Implemented Interfaces:

PendingImage.LoadCancelable

Direct Known Subclasses:

AsyncTaskCodeLoader

@LevelUpApi(contract=PUBLIC)
public abstract class LevelUpCodeLoader
extends Object
implements PendingImage.LoadCancelable

Load a LevelUp payment QR code. Extend this to implement the asynchronous loading of QR codes. As this class inherently interacts with multiple threads, thread requirements are noted on the individual methods.

Constructor Summary

Constructors

Constructor and Description
LevelUpCodeLoader(LevelUpQrCodeGenerator qrCodeGenerator, LevelUpCodeCache codeCache)

Method Summary

Modifier and Type	Method and Description
void	cancelLoad(String loadKey) Cancel the load associated with the given key.
void	cancelLoads() Cancel all loads.
protected boolean	dispatchOnImageLoaded(String key, LevelUpQrCodeGenerator.LevelUpQrCodeImage image) Dispatches calls to a previously registered PendingImage.OnImageLoaded.
protected LevelUpQrCodeGenerator.LevelUpQrCodeImage	generateQrCode(String key, String qrCodeContents) Generates the QR code using the supplied generator and caches the result.
protected LevelUpCodeCache	getCodeCache()
protected String	getKey(String qrCodeContents) Creates a key that's unique to the given contents for use with all image load tracking.
PendingImage<LevelUpQrCodeGenerator.LevelUpQrCodeImage>	getLevelUpCode(String qrCodeContents, PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded) Gets a minimally-small bitmap from the cache whose contents encode qrCodeContents.
protected LevelUpQrCodeGenerator	getQrCodeGenerator()
void	loadLevelUpCode(String codeData) Generate and cache the code image.
protected abstract void	onCancelLoad(String loadKey) Implement this to handle any load cancellation.
protected abstract void	onCancelLoads() Cancel all loads.
protected abstract void	onStartLoadInBackground(String qrCodeContents, String key, PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded) Implement this to start the loading of the given QR code into an image in the background.
protected void	registerOnImageLoadedCallback(String key, PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded) Register an PendingImage.OnImageLoaded callback with the given key.
protected void	startLoadInBackground(String qrCodeContents, String key, PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded) Start the loading of the given QR code into an image in the background.
protected void	unregisterOnImageLoadedCallback(String key) Remove the given PendingImage.OnImageLoaded callbacks.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LevelUpCodeLoader

public LevelUpCodeLoader(LevelUpQrCodeGenerator qrCodeGenerator,
                         LevelUpCodeCache codeCache)

Parameters:

qrCodeGenerator - the QR code generator to render the codes.

codeCache - the cache to use for this code loader.

Method Detail

cancelLoad

public final void cancelLoad(String loadKey)

Description copied from interface: PendingImage.LoadCancelable

Cancel the load associated with the given key.

Specified by:

cancelLoad in interface PendingImage.LoadCancelable

Parameters:

loadKey - the key.

cancelLoads

public final void cancelLoads()

Cancel all loads. To cancel an individual load, call cancelLoad(String) or PendingImage.cancelLoad(). This must be called on the main thread.

getLevelUpCode

public final PendingImage<LevelUpQrCodeGenerator.LevelUpQrCodeImage> getLevelUpCode(String qrCodeContents,
                                                                                    PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded)

Gets a minimally-small bitmap from the cache whose contents encode qrCodeContents. This returns a PendingImage, which will either contain the resulting image if the code has been cached or will be loaded eventually and the onImageLoaded callback will be called. This must be called on the main thread.

Parameters:

qrCodeContents - the data to display to the user. This is the raw string to encode in the QR code.

onImageLoaded - callback that gets called when the image is loaded. This will always be called on the UI thread and is called even if this class returns a cached result.

Returns:

a minimally-small bitmap representing the given code data.

loadLevelUpCode

public final void loadLevelUpCode(String codeData)

Generate and cache the code image. This is the same as getLevelUpCode(String, com.scvngr.levelup.core.ui.view.PendingImage.OnImageLoaded), but does not return a result to the user. This can be used for pre-caching codes. This must be called on the main thread.

Parameters:

codeData - the data to display to the user.

dispatchOnImageLoaded

protected final boolean dispatchOnImageLoaded(String key,
                                              LevelUpQrCodeGenerator.LevelUpQrCodeImage image)

Dispatches calls to a previously registered PendingImage.OnImageLoaded. The PendingImage.OnImageLoaded will be unregistered. This must be called after loading a QR code in the background. This must be called on the main thread.

Parameters:

key - the key under which the QR code is tracked.

image - the image of the QR code.

Returns:

true if the callback was called.

generateQrCode

@SlowOperation
protected final LevelUpQrCodeGenerator.LevelUpQrCodeImage generateQrCode(String key,
                                                                                        String qrCodeContents)

Generates the QR code using the supplied generator and caches the result. This should be called from a worker thread.

Parameters:

key - the key under which this QR code is tracked.

qrCodeContents - the contents of the QR code.

Returns:

the generated image.

getCodeCache

protected final LevelUpCodeCache getCodeCache()

Returns:

the code cache.

getKey

protected final String getKey(String qrCodeContents)

Creates a key that's unique to the given contents for use with all image load tracking.

Parameters:

qrCodeContents - the contents to create a key for.

Returns:

a unique key for the given contents.

getQrCodeGenerator

protected final LevelUpQrCodeGenerator getQrCodeGenerator()

Returns:

the QR code generator.

onCancelLoad

protected abstract void onCancelLoad(String loadKey)

Implement this to handle any load cancellation.

Parameters:

loadKey - the key under which the QR code is tracked.

onCancelLoads

protected abstract void onCancelLoads()

Cancel all loads. Implement this to stop any pending loads.

onStartLoadInBackground

protected abstract void onStartLoadInBackground(String qrCodeContents,
                                                String key,
                                                PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded)

Implement this to start the loading of the given QR code into an image in the background. If an existing request for the same content has been made, the second request will be dropped unless the previous request has been cancelled. This must be called on the main thread.

Subclasses shouldn't call this method directly, instead call startLoadInBackground(String, String, com.scvngr.levelup.core.ui.view.PendingImage.OnImageLoaded) )}.

Parameters:

qrCodeContents - the contents to render into a QR code.

key - the key under which the QR code is tracked.

onImageLoaded - called when the image has been loaded.

registerOnImageLoadedCallback

protected final void registerOnImageLoadedCallback(String key,
                                                   PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded)

Register an PendingImage.OnImageLoaded callback with the given key. This must be called on the main thread.

Parameters:

key - the key under which the image is tracked.

onImageLoaded - the callback to register.

startLoadInBackground

protected void startLoadInBackground(String qrCodeContents,
                                     String key,
                                     PendingImage.OnImageLoaded<LevelUpQrCodeGenerator.LevelUpQrCodeImage> onImageLoaded)

Start the loading of the given QR code into an image in the background. If an existing request for the same content has been made, the second request will be dropped unless the previous request has been cancelled. This must be called on the main thread.

Parameters:

qrCodeContents - the contents to render into a QR code.

key - the key under which the QR code is tracked.

onImageLoaded - called when the image has been loaded. Existing callbacks registered for this key will be overwritten unless this parameter is null.

unregisterOnImageLoadedCallback

protected final void unregisterOnImageLoadedCallback(String key)

Remove the given PendingImage.OnImageLoaded callbacks. This must be called on the main thread.

Parameters:

key - the key under which the image is tracked.