Android的 - 从一个URI来获得一个InputStream字节数组？ [英] Android - getting from a Uri to an InputStream to a byte array?

问题描述

我想从Android的开放的我们得到一个字节数组。

I'm trying to get from an Android Uri to a byte array.

我有以下的code，但它一直告诉我的字节数组是61字节长，即使该文件是相当大的 - 所以我认为这可能会开启乌里字符串成字节数组，而不是文件：（

I have the following code, but it keeps telling me that the byte array is 61 bytes long, even though the file is quite large - so I think it may be turning the Uri string into a byte array, rather than the file :(

  Log.d(LOG_TAG, "fileUriString = " + fileUriString);
  Uri tempuri = Uri.parse(fileUriString);
  InputStream is = cR.openInputStream(tempuri);
  String str=is.toString();
  byte[] b3=str.getBytes();
  Log.d(LOG_TAG, "len of data is " + imageByteArray.length
     + " bytes");

请有人可以帮我找出该怎么办？

Please can someone help me work out what to do?

输出为fileUriString =内容：//媒体/外部/视频/媒体/ 53和数据len为61字节

The output is "fileUriString = content://media/external/video/media/53" and "len of data is 61 bytes".

谢谢！

推荐答案

is.toString（）会给你的InputStream实例的字符串再presentation，而不是它的内容。

is.toString() will give you a String representation of the InputStream instance, not its content.

您需要阅读（）从InputStream到您的字节数组。有两个读的方法来做到这一点，阅读（）可以阅读一次一个字节，和<一href="http://developer.android.com/reference/java/io/InputStream.html#read%28byte%5b%5d%29">read(byte[]字节）读取从InputStream字节为你传递给它的字节数组。

You need to read() bytes from the InputStream into your array. There's two read methods to do that, read() which reads a single byte at a time, and read(byte[] bytes) which reads bytes from the InputStream into the byte array you pass to it.

更新：阅读给定了一个InputStream不具有长度为这样的字节，则需要读取的字节中，直到有一无所有。我建议创建一个方法，为自己喜欢的东西，这是一个很好的简单的起点（这就是我至少会做到这一点在Java中）。

Update: to read the bytes given that an InputStream does not have a length as such, you need to read the bytes until there is nothing left. I suggest creating a method for yourself something like this is a nice simple starting point (this is how I would do it in Java at least).

public byte[] readBytes(InputStream inputStream) throws IOException {
  // this dynamically extends to take the bytes you read
  ByteArrayOutputStream byteBuffer = new ByteArrayOutputStream();

  // this is storage overwritten on each iteration with bytes
  int bufferSize = 1024;
  byte[] buffer = new byte[bufferSize];

  // we need to know how may bytes were read to write them to the byteBuffer
  int len = 0;
  while ((len = inputStream.read(buffer)) != -1) {
    byteBuffer.write(buffer, 0, len);
  }

  // and then we can return your byte array.
  return byteBuffer.toByteArray();
}

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