为什么我得到java.io.IOException:Mark已失效？

Question

我正在尝试从网址下载imags然后解码它们.问题是,我不知道它们有多大,如果我立即解码它们,应用程序会因太大的图像而崩溃.

我正在做以下操作,它适用于大多数图像,但是对于其中一些图像,它会抛出java.io.IOException: Mark has been invalidated异常.这不是一个大小问题,因为它发生在75KB或120KB的图像上,而不是20MB或45KB的图像.此格式也不重要,因为它可能发生在jpg或png图像上.

pis是一个InputStream.

    Options opts = new BitmapFactory.Options();
    BufferedInputStream bis = new BufferedInputStream(pis);
    bis.mark(1024 * 1024);
    opts.inJustDecodeBounds = true;
    Bitmap bmImg=BitmapFactory.decodeStream(bis,null,opts);

    Log.e("optwidth",opts.outWidth+"");
    try {
        bis.reset();
        opts.inJustDecodeBounds = false;
        int ratio = opts.outWidth/800; 
        Log.e("ratio",String.valueOf(ratio));
        if (opts.outWidth>=800)opts.inSampleSize = ratio;

        return BitmapFactory.decodeStream(bis,null,opts);

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return null;
    }

Answer 1

我想你想要解码大图像.我是通过选择图库图片来做到的.

File photos= new File("imageFilePath that you select");
Bitmap b = decodeFile(photos);

"decodeFile(photos)"功能用于解码大图像.我认为你需要获得图像.png或.jpg formet.

 private Bitmap decodeFile(File f){
        try {
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(f),null,o);

            //Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE=70;
            int width_tmp=o.outWidth, height_tmp=o.outHeight;
            int scale=1;
            while(true){
                if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
                    break;
                width_tmp/=2;
                height_tmp/=2;
                scale++;
            }

            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize=scale;
            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
        } catch (FileNotFoundException e) {}
        return null;
    }

您可以使用imageView显示它.

ImageView img = (ImageView)findViewById(R.id.sdcardimage);
img.setImageBitmap(b);