关于异常：SkImageDecoder::Factory returned null

开发中遇到一个问题：

04-07 23:51:59.590: D/skia(7827): --- SkImageDecoder::Factory returned null

本来是下载一大批图片的，可是遇到了这个问题，图片没下载下来，

上网搜了一下，发现都是讲“是HttpURLConnection的问题，如果使用apache的HttpClient的话，就不会有问题了”

我一看，也以为是的，毕竟我也用了Java的HttpURLConnection，改了之后发现问题依然存在，恶心了一把。妹的，

只有一步步调试了，后来发现是图片压缩时的问题：BitmapFactory.decodeStream(is, null, opts);

就在这一步出了错，妹的，其他地方时这个地方就不会出错，怎么这个时候这地方出错了呢？

怎么这么恶心呢，，

明天继续调，，

现在是根据返回的bitmap去压缩图片，

code:

Bitmap bitmap = BitmapFactory.decodeStream(i, null, opt);Matrix matrix = new Matrix(); matrix.postScale(0.5f,0.5f); //长和宽放大缩小的比例Bitmap resizeBmp = Bitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);return resizeBmp;

看这个错误的提示： SkImageDecoder::Factory returned null，想来是BitmapFactory的问题，找到decodeStream代码：

 /**     * Decode an input stream into a bitmap. If the input stream is null, or     * cannot be used to decode a bitmap, the function returns null.     * The stream's position will be where ever it was after the encoded data     * was read.     *     * @param is The input stream that holds the raw data to be decoded into a     *           bitmap.     * @param outPadding If not null, return the padding rect for the bitmap if     *                   it exists, otherwise set padding to [-1,-1,-1,-1]. If     *                   no bitmap is returned (null) then padding is     *                   unchanged.     * @param opts null-ok; Options that control downsampling and whether the     *             image should be completely decoded, or just is size returned.     * @return The decoded bitmap, or null if the image data could not be     *         decoded, or, if opts is non-null, if opts requested only the     *         size be returned (in opts.outWidth and opts.outHeight)     */    public static Bitmap decodeStream(InputStream is, Rect outPadding, Options opts) {        // we don't throw in this case, thus allowing the caller to only check        // the cache, and not force the image to be decoded.        if (is == null) {            return null;        }        // we need mark/reset to work properly        if (!is.markSupported()) {            is = new BufferedInputStream(is, DECODE_BUFFER_SIZE);        }        // so we can call reset() if a given codec gives up after reading up to        // this many bytes. FIXME: need to find out from the codecs what this        // value should be.        is.mark(1024);        Bitmap bm;        boolean finish = true;        if (is instanceof AssetManager.AssetInputStream) {            final int asset = ((AssetManager.AssetInputStream) is).getAssetInt();            if (opts == null || (opts.inScaled && opts.inBitmap == null)) {                float scale = 1.0f;                int targetDensity = 0;                if (opts != null) {                    final int density = opts.inDensity;                    targetDensity = opts.inTargetDensity;                    if (density != 0 && targetDensity != 0) {                        scale = targetDensity / (float) density;                    }                }                bm = nativeDecodeAsset(asset, outPadding, opts, true, scale);                if (bm != null && targetDensity != 0) bm.setDensity(targetDensity);                finish = false;            } else {                bm = nativeDecodeAsset(asset, outPadding, opts);            }        } else {            // pass some temp storage down to the native code. 1024 is made up,            // but should be large enough to avoid too many small calls back            // into is.read(...) This number is not related to the value passed            // to mark(...) above.            byte [] tempStorage = null;            if (opts != null) tempStorage = opts.inTempStorage;            if (tempStorage == null) tempStorage = new byte[16 * 1024];            if (opts == null || (opts.inScaled && opts.inBitmap == null)) {                float scale = 1.0f;                int targetDensity = 0;                if (opts != null) {                    final int density = opts.inDensity;                    targetDensity = opts.inTargetDensity;                    if (density != 0 && targetDensity != 0) {                        scale = targetDensity / (float) density;                    }                }                bm = nativeDecodeStream(is, tempStorage, outPadding, opts, true, scale);                if (bm != null && targetDensity != 0) bm.setDensity(targetDensity);                finish = false;            } else {                bm = nativeDecodeStream(is, tempStorage, outPadding, opts);            }        }        if (bm == null && opts != null && opts.inBitmap != null) {            throw new IllegalArgumentException("Problem decoding into existing bitmap");        }        return finish ? finishDecode(bm, outPadding, opts) : bm;    }

其中的注释说明：

若图片数据不可被decoded,则返回空：“The decoded bitmap, or null if the image data could not be decoded”

应该是这个流不能被decoded,所以BitmapFactory.decodeSteam时返回null,但为什么不能被decode呢？

在这个BitmapFacotry中也没找到有关“SkImageDecoder::Factory returned null”的字符，在系统源码中找到文件：SkImageDecoder.cpp

其中：

bool SkImageDecoder::DecodeStream(SkStream* stream, SkBitmap* bm,                          SkBitmap::Config pref, Mode mode, Format* format) {    SkASSERT(stream);    SkASSERT(bm);    bool success = false;    SkImageDecoder* codec = SkImageDecoder::Factory(stream);    if (NULL != codec) {        success = codec->decode(stream, bm, pref, mode);        if (success && format) {            *format = codec->getFormat();        }        delete codec;    }    return success;}

在这里假如codec为空，则返回的success为false,然后系统哪里会根据这个返回值来提示那句提示呢？

先做项目，以后再解决这个问题。。