分类： 技术

(原文在 http://blog.renhao.org/2010/08/build-pptp-vpn-on-centos-5-5/comment-page-1/#comment-1682)很好用，一次就成功了，呵呵

前段时间想在自己的服务器上搭建个VPN，结果按照网上的很多方法弄下来却死活上不去。后来经过多次折腾，终于成功的架设了PPTP VPN。不敢保留，将这个经验分享出来，供自己今后参考的同时也能够让需要的朋友找到正确的安装方法。

Linux下常用的VPN服务有两个，一个是pptp，另一个则是openvpn。前者更简单一些，但是只有独立服务器和XEN VPS可以搭建；后者则没有任何限制。前者搭建出来的VPN，不需要特殊的VPN客户端，直接在Windows下创建VPN拨号连接即可；而后者需要安装一个客户端来进行拨号。

废话不说，下面我们就开始在CentOS 5.5下搭建pptp的VPN吧！本教程同样适用于CentOS 5.0~5.4的任意一个版本。 继续阅读“CentOS 5.5下搭建pptp VPN”

from stackOverFlow

太坑了。。。

My Android Java Application needs to record audio data into the RAM and process it. This is why I use the class “AudioRecord” and not the “MediaRecorder” (records only to file).

Till now, I used a busy loop polling with “read()” for the audio data. this has been working so far, but it peggs the CPU too much. Between two polls, I put the thread to sleep to avoid 100% CPU usage. However, this is not really a clean solution, since the time of the sleep is not guaranteed and you must subtract a security time in order not to loose audio snippets. This is not CPU optimal. I need as many free CPU cycles as possible for a parallel running thread.

Now I implemented the recording using the “OnRecordPositionUpdateListener”. This looks very promising and the right way to do it according the SDK Docs. Everything seems to work (opening the audio device, read()ing the data etc.) but the Listner is never called.

Does anybody know why?

Info: I am working with a real Device, not under the Emulator. The Recording using a Busy Loop basically works (however not satifiying). Only the Callback Listener is never called.

Here is a snippet from my Sourcecode:

public class myApplication extends Activity {

  /* audio recording */
  private static final int AUDIO_SAMPLE_FREQ = 16000;
  private static final int AUDIO_BUFFER_BYTESIZE = AUDIO_SAMPLE_FREQ * 2 * 3; // = 3000ms
  private static final int AUDIO_BUFFER_SAMPLEREAD_SIZE = AUDIO_SAMPLE_FREQ  / 10 * 2; // = 200ms

  private short[] mAudioBuffer = null; // audio buffer
  private int mSamplesRead; // how many samples are recently read
  private AudioRecord mAudioRecorder; // Audio Recorder

  ...

  private OnRecordPositionUpdateListener mRecordListener = new OnRecordPositionUpdateListener() {

    public void onPeriodicNotification(AudioRecord recorder) {
      mSamplesRead = recorder.read(mAudioBuffer, 0, AUDIO_BUFFER_SAMPLEREAD_SIZE);
      if (mSamplesRead > 0) {

        // do something here...

      }
    }

    public void onMarkerReached(AudioRecord recorder) {
      Error("What? Hu!? Where am I?");
    }
  };

  ...

  public void onCreate(Bundle savedInstanceState) {

  try {
      mAudioRecorder = new AudioRecord(
          android.media.MediaRecorder.AudioSource.MIC,
          AUDIO_SAMPLE_FREQ,
          AudioFormat.CHANNEL_CONFIGURATION_MONO,
          AudioFormat.ENCODING_PCM_16BIT,
          AUDIO_BUFFER_BYTESIZE);
    } catch (Exception e) {
      Error("Unable to init audio recording!");
    }

    mAudioBuffer = new short[AUDIO_BUFFER_SAMPLEREAD_SIZE];
    mAudioRecorder.setPositionNotificationPeriod(AUDIO_BUFFER_SAMPLEREAD_SIZE);
    mAudioRecorder.setRecordPositionUpdateListener(mRecordListener);
    mAudioRecorder.startRecording();

    /* test if I can read anything at all... (and yes, this here works!) */
    mSamplesRead = mAudioRecorder.read(mAudioBuffer, 0, AUDIO_BUFFER_SAMPLEREAD_SIZE);

  }
}

Answer:

I believe the problem is that you still need to do the read loop. If you setup callbacks, they will fire when you’ve read the number of frames that you specify for the callbacks. But you still need to do the reads. I’ve tried this and the callbacks get called just fine. Setting up a marker causes a callback when that number of frames has been read since the start of recording. In other words, you could set the marker far into the future, after many of your reads, and it will fire then. You can set the period to some bigger number of frames and that callback will fire every time that number of frames has been read. I think they do this so you can do low-level processing of the raw data in a tight loop, then every so often your callback can do summary-level processing. You could use the marker to make it easier to decide when to stop recording (instead of counting in the read loop).

好用，呵呵（http://www.eoeandroid.com/thread-103093-1-1.html）

int targetWidth = 100;
int targetHeight = 100;
Bitmap targetBitmap = Bitmap.createBitmap(
targetWidth,
targetHeight,
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(targetBitmap);
Path path = new Path();
path.addCircle(
((float)targetWidth - 1) / 2,
((float)targetHeight - 1) / 2,
(Math.min(((float)targetWidth), ((float)targetHeight)) / 2),
Path.Direction.CCW);
canvas.clipPath(path);
Bitmap sourceBitmap = BitmapFactory.decodeResource(
getResources(),
R.drawable.my_image);
canvas.drawBitmap(
sourceBitmap,
new Rect(0, 0, sourceBitmap.getWidth(), sourceBitmap.getHeight()),
new Rect(0, 0, targetWidth, targetHeight),
null);
ImageView imageView = (ImageView)findViewById(R.id.my_image_view);
imageView.setImageBitmap(targetBitmap);

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冲值，在线支付

后台，查看支付信息，已卖出vpn信息

vpn流量控制

vpn带宽限制

充值后自动生成帐号并启用程式。

恩，目前就这些，呵呵

scala编程写的果然很爽啊，哇哈哈。

很给力，很不错。