/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.volley.toolbox;
import java.io.InputStream;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.webkit.URLUtil;
import com.android.volley.DefaultRetryPolicy;
import com.android.volley.NetworkResponse;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.Response;
import com.android.volley.VolleyLog;
/**
* A canned request for getting an image at a given URL and calling
* back with a decoded Bitmap.
*/
public class ImageRequest extends Request<Bitmap> {
/** Socket timeout in milliseconds for image requests */
private static final int IMAGE_TIMEOUT_MS = 3000;
/** Default number of retries for image requests */
private static final int IMAGE_MAX_RETRIES = 2;
/** Default backoff multiplier for image requests */
private static final float IMAGE_BACKOFF_MULT = 2f;
private final Response.Listener<Bitmap> mListener;
private final Config mDecodeConfig;
private final int mMaxWidth;
private final int mMaxHeight;
private Context mContext;
/** Decoding lock so that we don't decode more than one image at a time (to avoid OOM's) */
private static final Object sDecodeLock = new Object();
/**
* 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.
*
* @param url URL of the image
* @param listener Listener to receive the decoded bitmap
* @param maxWidth Maximum width to decode this bitmap to, or zero for none
* @param maxHeight Maximum height to decode this bitmap to, or zero for
* none
* @param decodeConfig Format to decode the bitmap to
* @param errorListener Error listener, or null to ignore errors
*/
public ImageRequest(Context context,String url, Response.Listener<Bitmap> listener, int maxWidth, int maxHeight,
Config decodeConfig, Response.ErrorListener errorListener) {
super(Method.GET, url, errorListener);
setRetryPolicy(
new DefaultRetryPolicy(IMAGE_TIMEOUT_MS, IMAGE_MAX_RETRIES, IMAGE_BACKOFF_MULT));
mListener = listener;
mDecodeConfig = decodeConfig;
mMaxWidth = maxWidth;
mMaxHeight = maxHeight;
mContext = context;
// 如果加载的是本地图片，不放入disk-cache目录
if (url.startsWith("http") || url.startsWith("https")) {
setShouldCache(true);
} else {
setShouldCache(false);
}
setShouldGzip(false);
}
@Override
public Priority getPriority() {
return Priority.HIGH;
}
/**
* Scales one side of a rectangle to fit aspect ratio.
*
* @param maxPrimary Maximum size of the primary dimension (i.e. width for
* max width), or zero to maintain aspect ratio with secondary
* dimension
* @param maxSecondary Maximum size of the secondary dimension, or zero to
* maintain aspect ratio with primary dimension
* @param actualPrimary Actual size of the primary dimension
* @param actualSecondary Actual size of the secondary dimension
*/
// private static int getResizedDimension(int maxPrimary, int maxSecondary, int actualPrimary,
// int actualSecondary) {
// // If no dominant value at all, just return the actual.
// if (maxPrimary == 0 && maxSecondary == 0) {
// return actualPrimary;
// }
//
// // If primary is unspecified, scale primary to match secondary's scaling ratio.
// if (maxPrimary == 0) {
// double ratio = (double) maxSecondary / (double) actualSecondary;
// return (int) (actualPrimary * ratio);
// }
//
// if (maxSecondary == 0) {
// return maxPrimary;
// }
//
// double ratio = (double) actualSecondary / (double) actualPrimary;
// int resized = maxPrimary;
// if (resized * ratio > maxSecondary) {
// resized = (int) (maxSecondary / ratio);
// }
// return resized;
// }
@Override
protected Response<Bitmap> parseNetworkResponse(NetworkResponse response) {
// Serialize all decode on a global lock to reduce concurrent heap usage.
synchronized (sDecodeLock) {
try {
return doParse(response);
} catch (OutOfMemoryError e) {
VolleyLog.e("Caught OOM for %d byte image, url=%s", response.data.length, getUrl());
return Response.error(new ParseError(e));
}
}
}
/**
* The real guts of parseNetworkResponse. Broken out for readability.
*/
private Response<Bitmap> doParse(NetworkResponse response) {
Bitmap bitmap = null;
if (URLUtil.isNetworkUrl(getUrl())) {
byte[] data = response.data;
bitmap = BitmapDecoder.bytes2Bitmap(data, mDecodeConfig, mMaxWidth, mMaxHeight);
} else {
InputStream is = BitmapDecoder.getInputStream(mContext, getUrl());
bitmap = BitmapDecoder.inputStream2Bitmap(mContext, getUrl(),is, mDecodeConfig, mMaxWidth, mMaxHeight);
}
// BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
// Bitmap bitmap = null;
// if (mMaxWidth == 0 && mMaxHeight == 0) {
// decodeOptions.inPreferredConfig = mDecodeConfig;
// bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
// } else {
// // If we have to resize this image, first get the natural bounds.
// decodeOptions.inJustDecodeBounds = true;
// BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
// int actualWidth = decodeOptions.outWidth;
// int actualHeight = decodeOptions.outHeight;
//
// // Then compute the dimensions we would ideally like to decode to.
// int desiredWidth = getResizedDimension(mMaxWidth, mMaxHeight,
// actualWidth, actualHeight);
// int desiredHeight = getResizedDimension(mMaxHeight, mMaxWidth,
// actualHeight, actualWidth);
//
// // Decode to the nearest power of two scaling factor.
// decodeOptions.inJustDecodeBounds = false;
// // TODO(ficus): Do we need this or is it okay since API 8 doesn't support it?
// // decodeOptions.inPreferQualityOverSpeed = PREFER_QUALITY_OVER_SPEED;
// decodeOptions.inSampleSize =
// findBestSampleSize(actualWidth, actualHeight, desiredWidth, desiredHeight);
// Bitmap tempBitmap =
// BitmapFactory.decodeByteArray(data, 0, data.length, decodeOptions);
//
// // If necessary, scale down to the maximal acceptable size.
// if (tempBitmap != null && (tempBitmap.getWidth() > desiredWidth ||
// tempBitmap.getHeight() > desiredHeight)) {
// bitmap = Bitmap.createScaledBitmap(tempBitmap,
// desiredWidth, desiredHeight, true);
// tempBitmap.recycle();
// } else {
// bitmap = tempBitmap;
// }
// }
if (bitmap == null) {
return Response.error(new ParseError(response));
} else {
return Response.success(bitmap, HttpHeaderParser.parseCacheHeaders(response));
}
}
@Override
protected void deliverResponse(Bitmap response) {
mListener.onResponse(response);
}
/**
* Returns the largest power-of-two divisor for use in downscaling a bitmap
* that will not result in the scaling past the desired dimensions.
*
* @param actualWidth Actual width of the bitmap
* @param actualHeight Actual height of the bitmap
* @param desiredWidth Desired width of the bitmap
* @param desiredHeight Desired height of the bitmap
*/
// Visible for testing.
// static int findBestSampleSize(
// int actualWidth, int actualHeight, int desiredWidth, int desiredHeight) {
// double wr = (double) actualWidth / desiredWidth;
// double hr = (double) actualHeight / desiredHeight;
// double ratio = Math.min(wr, hr);
// float n = 1.0f;
// while ((n * 2) <= ratio) {
// n *= 2;
// }
//
// return (int) n;
// }
}
