java - DecodeStream 在存储位图中时抛出 null

Question

这是我的代码...我在 imageBitmap = BitmapFactory.decodeStream(is2,null, options); 处收到异常 NULL;

第一次可以解码，但为什么现在，decodeStream 抛出 null ？

 public void showImageThumb(FileInputStream is)
        {
            final int IMAGE_MAX_SIZE = 100;
            FileInputStream is2 = is;
            BitmapFactory.Options options=new BitmapFactory.Options();
            options.inSampleSize = 4;
            Bitmap imageBitmap = BitmapFactory.decodeStream(is,null, options);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int height = options.outHeight;
            int width = options.outWidth;
            int scale = 1;
            if ( height > IMAGE_MAX_SIZE || width > IMAGE_MAX_SIZE) 
            {
                 scale = (int)Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE / (double) Math.max(options.outHeight, options.outWidth)) / Math.log(0.5)));
            }
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            options = new BitmapFactory.Options();
            options.inSampleSize = scale*2;
            imageBitmap = BitmapFactory.decodeStream(is2,null, options);
            height = options.outHeight;
            width = options.outWidth;
            imageBitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos); //ERROR HERE 
            imageSelectedThumb = baos.toByteArray();

Answer 1

你会得到一个空指针异常，因为你正在复制

is

引用位于

is2

所以当你关闭is时，你也关闭了is2。您必须创建一个新的 InpustStream

而不是将 is 分配给 is2