毕加索：无法从 InputStream 加载位图到 ImageView

问题描述

我收到一个代表我的图像的 InputStream，我尝试通过 Picasso 将它加载到 ImageView。

    public static Picasso getCustomPicasso(InputStream fileInputStream,Context context) {
        return new Picasso.Builder(context)
                .listener((picasso,uri,exception) -> exception.printstacktrace())
                .addRequestHandler(new RequestHandler() {
                    @Override
                    public boolean canHandleRequest(Request data) {
                        return true;
                    }

                    @Override
                    public Result load(Request request,int networkPolicy) {
                        return new Result(BitmapFactory.decodeStream(fileInputStream),Picasso.LoadedFrom.NETWORK);
                    }
                }).build();
    }

getCustomPicasso(fileInputStream,context)
                    .load(fileName)
                    .resize(0,720)
                    .into(new Target() {
                        @Override
                        public void onBitmapLoaded(Bitmap bitmap,Picasso.LoadedFrom from) {
                            Logger.d(TAG,"Image loaded from the network.");
                            imageView.setimageBitmap(bitmap);
                        }

                        @Override
                        public void onBitmapFailed(Exception e,Drawable errorDrawable) {
                            Logger.e(TAG,"Image load from the network Failed: " + e.getMessage());
                            e.printstacktrace();
                        }

                        @Override
                        public void onPrepareLoad(Drawable placeHolderDrawable) {
                        }
                    });

一般情况下它可以正常工作，但如果图像尺寸大/分辨率高，则图像不会加载到 ImageView。我还尝试重新调整 Bitmap 的大小，就像 here 所描述的那样。我在 decodeSampledBitmapFromInputStream 的 load 方法中调用 RequestHandler 方法而不是 BitmapFactory.decodeStream(fileInputStream)，它返回 null。

public static Picasso getCustomPicasso(InputStream fileInputStream,int networkPolicy) {
                        return new Result(decodeSampledBitmapFromInputStream(fileInputStream,100,100),Picasso.LoadedFrom.NETWORK);
                    }
                }).build();
    }

public static Bitmap decodeSampledBitmapFromInputStream(InputStream fileInputStream,int reqWidth,int reqHeight) {

        // First decode with inJustDecodeBounds=true to check dimensions
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(res,resId,options);
        BitmapFactory.decodeStream(fileInputStream,null,options);

        // Calculate inSampleSize
        options.inSampleSize = calculateInSampleSize(options,reqWidth,reqHeight);

        // Decode bitmap with inSampleSize set
        options.inJustDecodeBounds = false;

        //return BitmapFactory.decodeResource(res,options);
        return BitmapFactory.decodeStream(fileInputStream,options);
    }

    private static int calculateInSampleSize(BitmapFactory.Options options,int reqHeight) {
        // Raw height and width of image
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {

            final int halfheight = height / 2;
            final int halfWidth = width / 2;

            // Calculate the largest inSampleSize value that is a power of 2 and keeps both
            // height and width larger than the requested height and width.
            while ((halfheight / inSampleSize) >= reqHeight && (halfWidth / inSampleSize) >= reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }

但在这种情况下，我收到 null Bitmap 并且根本不显示任何图像。我想知道如何解决这个问题。任何帮助将不胜感激。

解决方法

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