安卓。无缓冲的IO

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问题描述

我想使用非阻止IO读取背景过程中的流/输出.有人可以给我一个有关如何在Android上使用非阻止IO的示例吗?

感谢您的帮助.

推荐答案

这是我使用的类从Internet下载文件或复制文件系统中的文件以及我如何使用它:

// 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);

还有选择器方法，这里有一些关于选择器，频道和线程的很棒的(Java)教程:

http://jfarcand.wordpress.com/2006/05/05/30/tricks-and-with-with-nio-nio-part-i------------------------------------ li>
http://jfarcand.wordpress.com/2006/07/06/tricks-and-tricks-and-with-with-nio-part-ii--i-why-selectionkey-selectionkey-attach-is-is-evil/
http://jfarcand.wordpress.com/2006/07/07/tricks-and-pricks-and-with-with-nio-part-iii-part-iii-to-thread-thread-thread-or-thread-or-not-not-not-not-not-not-to-thread/
http://jfarcand.wordpress.com/2006/07/19/httpweblogs-java-netblog2006071919tricks-and-and-tips-and-tips-nio-part-part-iv-meet-selectors/
http://jfarcand.wordpress.com/2006/09/21/tricks-and-pricks-and-with-with-nio-part-nio-part-vart-v-ssl-v-ssl-nio-nio-friend-oriend-or-friend-or-foe/-

其他推荐答案

背景操作可以在Android中以多种方式完成.我建议您使用asynctask:

private class LongOperation extends AsyncTask<String, Void, String> {

 @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
  }
}

然后您像这样执行它:

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

参考: xoriant.com

在Doinbackground方法中，您可以将文件访问内容放置. 可以在Android开发人员站点中找到文件访问的参考.

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问题描述

I want to use an Non Blocking IO to read a stream/output from a background process.Can anyone give me an example on how to use the Non Blocking IO on Android?

Thanks for the help.

其他推荐答案

background operation can be done in many ways in Android. I suggest you to use AsyncTask:

private class LongOperation extends AsyncTask<String, Void, String> {

 @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
  }
}

Then you execute it like this:

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

reference: xoriant.com

In the doInBackground method, you can put your file access stuff. reference for file access can be found in the android developer site.

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