com.android.volley.toolbox

Class ImageRequest

java.lang.Object

com.android.volley.Request<Bitmap>

com.android.volley.toolbox.ImageRequest

All Implemented Interfaces:

java.lang.Comparable<Request<Bitmap>>

public class ImageRequest
extends Request<Bitmap>

A canned request for getting an image at a given URL and calling back with a decoded Bitmap.

Nested Class Summary

Nested classes/interfaces inherited from class com.android.volley.Request

Request.Method, Request.Priority

Field Summary

Fields

Modifier and Type	Field and Description
private static float	IMAGE_BACKOFF_MULT Default backoff multiplier for image requests
private static int	IMAGE_MAX_RETRIES Default number of retries for image requests
private static int	IMAGE_TIMEOUT_MS Socket timeout in milliseconds for image requests
private Config	mDecodeConfig
private Response.Listener<Bitmap>	mListener
private int	mMaxHeight
private int	mMaxWidth
private static java.lang.Object	sDecodeLock Decoding lock so that we don't decode more than one image at a time (to avoid OOM's)

Constructor Summary

Constructors

Constructor and Description
ImageRequest(java.lang.String url, Response.Listener<Bitmap> listener, int maxWidth, int maxHeight, Config decodeConfig, Response.ErrorListener errorListener) Creates a new image request, decoding to a maximum specified width and height.

Method Summary

Modifier and Type	Method and Description
protected void	deliverResponse(Bitmap response) Subclasses must implement this to perform delivery of the parsed response to their listeners.
private Response<Bitmap>	doParse(NetworkResponse response) The real guts of parseNetworkResponse.
(package private) static int	findBestSampleSize(int actualWidth, int actualHeight, int desiredWidth, int desiredHeight) Returns the largest power-of-two divisor for use in downscaling a bitmap that will not result in the scaling past the desired dimensions.
Request.Priority	getPriority() Returns the Request.Priority of this request; Request.Priority.NORMAL by default.
private static int	getResizedDimension(int maxPrimary, int maxSecondary, int actualPrimary, int actualSecondary) Scales one side of a rectangle to fit aspect ratio.
protected Response<Bitmap>	parseNetworkResponse(NetworkResponse response) Subclasses must implement this to parse the raw network response and return an appropriate response type.

Methods inherited from class com.android.volley.Request

addMarker, cancel, compareTo, deliverError, getBody, getBodyContentType, getCacheEntry, getCacheKey, getHeaders, getMethod, getParams, getParamsEncoding, getPostBody, getPostBodyContentType, getPostParams, getPostParamsEncoding, getRetryPolicy, getSequence, getTag, getTimeoutMs, getTrafficStatsTag, getUrl, hasHadResponseDelivered, isCanceled, markDelivered, parseNetworkError, setCacheEntry, setRequestQueue, setRetryPolicy, setSequence, setShouldCache, setTag, shouldCache, toString

Methods inherited from class java.lang.Object

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

Field Detail

IMAGE_TIMEOUT_MS

private static final int IMAGE_TIMEOUT_MS

Socket timeout in milliseconds for image requests

See Also:

Constant Field Values

IMAGE_MAX_RETRIES

private static final int IMAGE_MAX_RETRIES

Default number of retries for image requests

See Also:

Constant Field Values

IMAGE_BACKOFF_MULT

private static final float IMAGE_BACKOFF_MULT

Default backoff multiplier for image requests

See Also:

Constant Field Values

mListener

private final Response.Listener<Bitmap> mListener

mDecodeConfig

private final Config mDecodeConfig

mMaxWidth

private final int mMaxWidth

mMaxHeight

private final int mMaxHeight

sDecodeLock

private static final java.lang.Object sDecodeLock

Decoding lock so that we don't decode more than one image at a time (to avoid OOM's)

Constructor Detail

ImageRequest

public ImageRequest(java.lang.String url,
                    Response.Listener<Bitmap> listener,
                    int maxWidth,
                    int maxHeight,
                    Config decodeConfig,
                    Response.ErrorListener errorListener)

Creates a new image request, decoding to a maximum specified width and height. If both width and height are zero, the image will be decoded to its natural size. If one of the two is nonzero, that dimension will be clamped and the other one will be set to preserve the image's aspect ratio. If both width and height are nonzero, the image will be decoded to be fit in the rectangle of dimensions width x height while keeping its aspect ratio.

Parameters:

url - URL of the image

listener - Listener to receive the decoded bitmap

maxWidth - Maximum width to decode this bitmap to, or zero for none

maxHeight - Maximum height to decode this bitmap to, or zero for none

decodeConfig - Format to decode the bitmap to

errorListener - Error listener, or null to ignore errors

Method Detail

getPriority

public Request.Priority getPriority()

Description copied from class: Request

Returns the Request.Priority of this request; Request.Priority.NORMAL by default.

Overrides:

getPriority in class Request<Bitmap>

getResizedDimension

private static int getResizedDimension(int maxPrimary,
                                       int maxSecondary,
                                       int actualPrimary,
                                       int actualSecondary)

Scales one side of a rectangle to fit aspect ratio.

Parameters:

maxPrimary - Maximum size of the primary dimension (i.e. width for max width), or zero to maintain aspect ratio with secondary dimension

maxSecondary - Maximum size of the secondary dimension, or zero to maintain aspect ratio with primary dimension

actualPrimary - Actual size of the primary dimension

actualSecondary - Actual size of the secondary dimension

parseNetworkResponse

protected Response<Bitmap> parseNetworkResponse(NetworkResponse response)

Description copied from class: Request

Subclasses must implement this to parse the raw network response and return an appropriate response type. This method will be called from a worker thread. The response will not be delivered if you return null.

Specified by:

parseNetworkResponse in class Request<Bitmap>

Parameters:

response - Response from the network

Returns:

The parsed response, or null in the case of an error

doParse

private Response<Bitmap> doParse(NetworkResponse response)

The real guts of parseNetworkResponse. Broken out for readability.

deliverResponse

protected void deliverResponse(Bitmap response)

Description copied from class: Request

Subclasses must implement this to perform delivery of the parsed response to their listeners. The given response is guaranteed to be non-null; responses that fail to parse are not delivered.

Specified by:

deliverResponse in class Request<Bitmap>

Parameters:

response - The parsed response returned by Request.parseNetworkResponse(NetworkResponse)

findBestSampleSize

static int findBestSampleSize(int actualWidth,
                              int actualHeight,
                              int desiredWidth,
                              int desiredHeight)

Returns the largest power-of-two divisor for use in downscaling a bitmap that will not result in the scaling past the desired dimensions.

Parameters:

actualWidth - Actual width of the bitmap

actualHeight - Actual height of the bitmap

desiredWidth - Desired width of the bitmap

desiredHeight - Desired height of the bitmap