Android：无缓冲的IO

我想使用非阻塞IO来读取后台进程的流/输出。任何人都可以举例说明如何在Android上使用非阻塞IO？

谢谢您的帮助。

Answer 1

这是我用来从互联网下载文件或复制文件系统中的文件以及如何使用它的类：

// Download a file to /data/data/your.app/files new DownloadFile(ctxt, "http://yourfile", ctxt.openFileOutput("destinationfile.ext", Context.MODE_PRIVATE)); // Copy a file from raw resource to the files directory as above InputStream in = ctxt.getResources().openRawResource(R.raw.myfile); OutputStream out = ctxt.openFileOutput("filename.ext", Context.MODE_PRIVATE); final ReadableByteChannel ic = Channels.newChannel(in); final WritableByteChannel oc = Channels.newChannel(out); DownloadFile.fastChannelCopy(ic, oc); 

还有Selector方法，这里有一些关于选择器，通道和线程的优秀（Java）教程：

1. http://jfarcand.wordpress.com/2006/05/30/tricks-and-tips-with-nio-part-i-why-you-must-handle-op_write
2. http://jfarcand.wordpress.com/2006/07/06/tricks-and-tips-with-nio-part-ii-why-selectionkey-attach-is-evil/
3. http://jfarcand.wordpress.com/2006/07/07/tricks-and-tips-with-nio-part-iii-to-thread-or-not-to-thread/
4. http://jfarcand.wordpress.com/2006/07/19/httpweblogs-java-netblog20060719tricks-and-tips-nio-part-iv-meet-selectors/
5. http://jfarcand.wordpress.com/2006/09/21/tricks-and-tips-with-nio-part-v-ssl-and-nio-friend-or-foe/

Answer 2

在Android中可以通过多种方式完成后台操作。 我建议你使用AsyncTask：

 private class LongOperation extends AsyncTask { @Override protected String doInBackground(String... params) { // perform long running operation operation return null; } /* (non-Javadoc) * @see android.os.AsyncTask#onPostExecute(java.lang.Object) */ @Override protected void onPostExecute(String result) { // execution of result of Long time consuming operation } /* (non-Javadoc) * @see android.os.AsyncTask#onPreExecute() */ @Override protected void onPreExecute() { // Things to be done before execution of long running operation. For example showing ProgessDialog } /* (non-Javadoc) * @see android.os.AsyncTask#onProgressUpdate(Progress[]) */ @Override protected void onProgressUpdate(Void... values) { // Things to be done while execution of long running operation is in progress. For example updating ProgessDialog } } 

然后你像这样执行它：

 public void onClick(View v) { new LongOperation().execute(""); } 

参考： xoriant.com

在doInBackground方法中，您可以放置​​文件访问内容。 可以在android开发者站点中找到文件访问的参考。