阅读使用Android的Stream类从SD卡的二进制文件 [英] Reading binary file from sdcard using Stream classes in android

问题描述

任何人可以有任何想法如何读取使用流一样的InputStream，CountingInputStream或SwappedDataInputStream？

Can anybody have any idea how to read a binary file which resides in sdcard using Streams, like Inputstream, CountingInputStream or SwappedDataInputStream?

我现在用这三个流读取一个文件，该文件目前在Resouces文件夹中，但现在我想移动在SD卡的文件，但因为我已经做了这么多工作，我不能改变这些流，我无法滚动回我的工作。
我正在做这种方式，但其给我FileNotFoundException异常。我需要你的帮助，请。

I am using these three streams to read a file which is currently in the Resouces folder, but now i want to move that file in sdcard but I cannot change these stream because I have done so much work on it and I cannot roll back my work. i am doing it this way but its giving me FileNotFoundException. i need your help please.

AssetManager assetManager = getResources（）getAssets（）;最终文件
  文件夹=新的文件（Environment.getExternalStorageDirectory（）+/图）;
         布尔成功= FALSE;如果（！folder.exists（））{
             成功= folder.mkdir（）; }其他{
             Log.i（文件夹中已经存在，文件夹已经存在）; }

AssetManager assetManager = getResources().getAssets(); final File folder = new File(Environment.getExternalStorageDirectory() + "/map"); boolean success = false; if(!folder.exists()) { success = folder.mkdir(); } else { Log.i("folder already exists", "folder already exists"); }

尝试{=的IStream
  assetManager.open(Environment.getExternalStorageDirectory().getAbsolutePath().concat(\"/map/map.amf\"));
                                }赶上（IOException异常五）{// TODO自动生成catch块e.printStackTrace（）; }顺=新
  CountingInputStream（istream的）;输入=新
  SwappedDataInputStream（CIS）;

try { iStream = assetManager.open(Environment.getExternalStorageDirectory().getAbsolutePath().concat("/map/map.amf")); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } cis = new CountingInputStream(iStream); input = new SwappedDataInputStream(cis);

非常感谢任何建议。

推荐答案

这是一个简单的方法，它只是复制输入流的输出流的内容：

This is a simple method that just copies the content of an input stream to an output stream:

    /**
     * Copy the content of the input stream into the output stream, using a
     * temporary byte array buffer whose size is defined by
     * {@link #IO_BUFFER_SIZE}.
     * 
     * @param in
     *            The input stream to copy from.
     * @param out
     *            The output stream to copy to.
     * 
     * @throws java.io.IOException
     *             If any error occurs during the copy.
     */
    public static void copy(InputStream in, OutputStream out)
                    throws IOException {
            byte[] b = new byte[IO_BUFFER_SIZE];
            int read;
            while ((read = in.read(b)) != -1) {
                    out.write(b, 0, read);
            }
    }

它采取从一个应用程序，我前一阵子做：的http://$c$c.google.com/p/meneameandroid/source/browse/trunk/src/com/dcg/util/IOUtilities.java

和以确保目录存在要读/写数据我用的是这样的：

And to make sure the dir exists where you want to write/read your data I used something like this:

    /**
     * Prepares the SDCard with all we need
     */
    private void prepareSDCard() {
        // Create app dir in SDCard if possible
        File path = new File("/sdcard/MyAppDirectory/");
        if(! path.isDirectory()) {
            if ( path.mkdirs() )
            {
                Log.d(TAG,"Directory created: /sdcard/MyAppDirectory");
            }
            else
            {
                Log.w(TAG,"Failed to create directory: /sdcard/MyAppDirectory");
            }
        }
    }

的写权限/从SD卡读的是：

The permission to write/read from the SD card is:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

的编辑：Linkes更新的

这篇关于阅读使用Android的Stream类从SD卡的二进制文件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IT屋！