德codeStream返回null

问题描述

我试图通过位调整教程 - 唯一的区别是，我使用去codeStream而不是de codeResource。很奇怪，但德codeStream，无需任何操作，给了我一个位图OBJ，但是当我通过德codeSampledBitmapFromStream由于某种原因返回null。如何解决呢？

这里的code我用：

 保护处理程序_onPromoBlocksLoad =新的处理程序（）{
        @覆盖
        公共无效在DispatchMessage（信息MSG）{
            PromoBlocksContainer C =（PromoBlocksContainer）_promoBlocksFactory.getResponse（）;
            HTT prequest请求=新HTT prequest（c.getPromoBlocks（）得到（0）.getSmallThumbnail（））;

            BitmapFactory.Options选项=新BitmapFactory.Options（）;
            options.inJustDe codeBounds = TRUE;
            为InputStream流;
            ImageView的V =（ImageView的）findViewById（R.id.banner）;
            尝试 {
                流= request.getStream（）;

                //v.setImageBitmap(BitmapFactory.de$c$cStream(stream））;做工精细
                位图IMG =去codeSampledBitmapFromStream（流v.getWidth（），v.getHeight（））;
                v.setImageBitmap（IMG）;
            }赶上（IOException异常E1）{
                // TODO自动生成的catch块
                e1.printStackTrace（）;
            }
        }
    };

    公共静态INT calculateInSampleSize（BitmapFactory.Options选项，诠释reqWidth，诠释reqHeight）{
        最终诠释身高= options.outHeight;
        最终诠释宽度= options.outWidth;
        INT inSampleSize = 1;

        如果（高度＆GT; reqHeight ||宽度GT; reqWidth）{
            如果（宽＆GT;高度）{
                inSampleSize = Math.round（（浮动）的高度/（浮点）reqHeight）;
            } 其他 {
                inSampleSize = Math.round（（浮点）宽/（浮点）reqWidth）;
            }
        }
        返回inSampleSize;
    }

    公共静态位图德codeSampledBitmapFromStream（InputStream的资源，INT reqWidth，诠释reqHeight）{
        BitmapFactory.Options选项=新BitmapFactory.Options（）;
        options.inJustDe codeBounds = TRUE;
        BitmapFactory.de codeStream（RES，空，期权）;
        options.inSampleSize = calculateInSampleSize（选项，reqWidth，reqHeight）;
        options.inJustDe codeBounds = FALSE;
        位图IMG = BitmapFactory.de codeStream（RES，空，期权）; //给出空
        返回IMG;
    }
 

解决方案

但问题是，一旦你使用一个InputStream从HttpURLConnection类，您不能倒带，并使用相同的InputStream再次 。因此，你必须创建一个新的InputStream为图像的实际采样。否则，我们不得不放弃了http请求。

  request.abort（）;
 

I'm trying to adopt bitmap resizing tutorial - the only difference is that I use decodeStream instead of decodeResource. It's strange but decodeStream, without any manipulations, gives me a bitmap obj, but when I go through decodeSampledBitmapFromStream it returns null for some reason.How do I fix it ?

Here's the code I use:

protected Handler _onPromoBlocksLoad = new Handler() {
        @Override
        public void dispatchMessage(Message msg) {
            PromoBlocksContainer c = (PromoBlocksContainer) _promoBlocksFactory.getResponse();
            HttpRequest request = new HttpRequest(c.getPromoBlocks().get(0).getSmallThumbnail());

            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            InputStream stream;
            ImageView v = (ImageView) findViewById(R.id.banner);
            try {
                stream = request.getStream();

                //v.setImageBitmap(BitmapFactory.decodeStream(stream)); Works fine
                Bitmap img = decodeSampledBitmapFromStream(stream, v.getWidth(), v.getHeight());
                v.setImageBitmap(img);
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }
    };

    public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            if (width > height) {
                inSampleSize = Math.round((float)height / (float)reqHeight);
            } else {
                inSampleSize = Math.round((float)width / (float)reqWidth);
            }
        }
        return inSampleSize;
    }

    public static Bitmap decodeSampledBitmapFromStream(InputStream res, int reqWidth, int reqHeight) {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(res, null, options);
        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
        options.inJustDecodeBounds = false;
        Bitmap img =  BitmapFactory.decodeStream(res, null, options); // Gives  null
        return img;
    }

解决方案

The problem was that once you've used an InputStream from a HttpUrlConnection, you can't rewind and use the same InputStream again. Therefore you have to create a new InputStream for the actual sampling of the image. Otherwise we have to abort the http request.

request.abort();

这篇关于德codeStream返回null的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！