sheng00 的所有文章

Android创建sdcard详细图解

Android

Android应用广泛，应用方式灵活，可以在模拟器中进行相应修改实现许多特定的功能需求。我们在这里就先来了解一下Android创建sdcard的具体方法，从中感受一下这一操作系统的相关特性。

Android创建sdcard步骤一、cmd进入tools目录输入mksdcard -l mycard 100M F:mysdcard.img

1. mycard命令可以使用三种尺寸：字节、K和M。如果只使用数字，表示字节。后面还可以跟K，如262144K，也表示256M。

2. mycard建立的虚拟文件最小为8M，也就是说，模拟器只支持大于8M的虚拟文件。

3. -l命令行参数表示虚拟磁盘的卷标，可以没有该参数。

4. 虚拟文件的扩展名可以是任意的，如mycard.abc。

5. mksdcard命令不会自动建立不存在的目录，因此，在执行上面命令之前，要先在当前目录中建立一个card目录。

6. mksdcard命令是按实际大小生成的sdcard虚拟文件。也就是说，生成256M的虚拟文件的尺寸就是256M，如果生成较大的虚拟文件，要看看自己的硬盘空间够不够哦！

Android创建sdcard步骤二、激活sdcard

1.命令行输入：emulator -avd my_android1.5 -sdcard F:mysdcard.img

我在命令行输入激活不了，不知为什么！待解决！

emulator: ERROR: the user data image is used by another emulator. aborting

2.如果在开发环境（Eclipse）中，可以在Run Configuration对话框中设置启动参数

或者在Preferences–>Android–>Launch加入

Android创建sdcard步骤三、sdcard中加入内容

F:android-sdk-windows-1.5_r3tools>adb push E:Xunleigive.mp3 /sdcard/give.mp3

mp3 frame header

未分类


AAAAAAAA AAABBCCD EEEEFFGH IIJJKLMM

Sign Length
(bits)		 Position
(bits)		 Description
A 11 (31-21) Frame sync (all bits must be set)
B 2 (20,19) MPEG Audio version ID
00 – MPEG Version 2.5 (later extension of MPEG 2)
01 – reserved
10 – MPEG Version 2 (ISO/IEC 13818-3)
11 – MPEG Version 1 (ISO/IEC 11172-3)

Note: MPEG Version 2.5 was added lately to the MPEG 2 standard.
It is an extension used for very low bitrate files, allowing
the use of lower sampling frequencies. If your decoder does
not support this extension, it is recommended for you to use
12 bits for synchronization instead of 11 bits.

C 2 (18,17) Layer description
00 – reserved
01 – Layer III
10 – Layer II
11 – Layer I
D 1 (16) Protection bit
0 – Protected by CRC (16bit CRC follows header)
1 – Not protected
E 4 (15,12) Bitrate index

bits V1,L1 V1,L2 V1,L3 V2,L1 V2, L2 & L3
0000 free free free free free
0001 32 32 32 32 8
0010 64 48 40 48 16
0011 96 56 48 56 24
0100 128 64 56 64 32
0101 160 80 64 80 40
0110 192 96 80 96 48
0111 224 112 96 112 56
1000 256 128 112 128 64
1001 288 160 128 144 80
1010 320 192 160 160 96
1011 352 224 192 176 112
1100 384 256 224 192 128
1101 416 320 256 224 144
1110 448 384 320 256 160
1111 bad bad bad bad bad

NOTES: All values are in kbps
V1 – MPEG Version 1
V2 – MPEG Version 2 and Version 2.5
L1 – Layer I
L2 – Layer II
L3 – Layer III

“free” means free format. The free bitrate must
remain constant, an must be lower than the maximum allowed
bitrate. Decoders are not required to support decoding of
free bitrate streams.
“bad” means that the value is unallowed.

MPEG files may feature variable bitrate (VBR). Each frame
may then be created with a different bitrate. It may be used
in all layers. Layer III decoders must support this method.
Layer I & II decoders may support it.

For Layer II there are some combinations of bitrate and mode
which are not allowed. Here is a list of allowed combinations.

bitrate
single channel
stereo
intensity stereo
dual channel
free
yes
yes
yes
yes
32
yes
no
no
no
48
yes
no
no
no
56
yes
no
no
no
64
yes
yes
yes
yes
80
yes
no
no
no
96
yes
yes
yes
yes
112
yes
yes
yes
yes
128
yes
yes
yes
yes
160
yes
yes
yes
yes
192
yes
yes
yes
yes
224
no
yes
yes
yes
256
no
yes
yes
yes
320
no
yes
yes
yes
384
no
yes
yes
yes
F 2 (11,10) Sampling rate frequency index

bits MPEG1 MPEG2 MPEG2.5
00 44100 Hz 22050 Hz 11025 Hz
01 48000 Hz 24000 Hz 12000 Hz
10 32000 Hz 16000 Hz 8000 Hz
11 reserv. reserv. reserv.
G 1 (9) Padding bit
0 – frame is not padded
1 – frame is padded with one extra slot

Padding is used to exactly fit the bitrate.As an example: 128kbps
44.1kHz layer II uses a lot of 418 bytes and some of 417 bytes
long frames to get the exact 128k bitrate. For Layer I slot
is 32 bits long, for Layer II and Layer III slot is 8 bits long.
H 1 (8) Private bit. This one is only informative.
I 2 (7,6) Channel Mode
00 – Stereo
01 – Joint stereo (Stereo)
10 – Dual channel (2 mono channels)
11 – Single channel (Mono)

Note: Dual channel files are made of two independant mono channel.
Each one uses exactly half the bitrate of the file. Most decoders
output them as stereo, but it might not always be the case.
    One example of use would be some speech
in two different languages carried in the same bitstream, and
then an appropriate decoder would decode only the choosen language.

J 2 (5,4) Mode extension (Only used in Joint stereo)

Mode extension is used to join informations that are of no
use for stereo effect, thus reducing needed bits. These bits
are dynamically determined by an encoder in Joint stereo mode,
and Joint Stereo can be changed from one frame to another,
or even switched on or off.

Complete frequency range of MPEG file is divided in subbands
There are 32 subbands. For Layer I & II these two bits determine
frequency range (bands) where intensity stereo is applied.
For Layer III these two bits determine which type of joint
stereo is used (intensity stereo or m/s stereo). Frequency
range is determined within decompression algorithm.

Layer I and II Layer III
value Layer I & II
00 bands 4 to 31
01 bands 8 to 31
10 bands 12 to 31
11 bands 16 to 31
Intensity stereo MS stereo
off off
on off
off on
on on
K 1 (3) Copyright
0 – Audio is not copyrighted
1 – Audio is copyrighted

The copyright has the same meaning as the copyright bit on CDs
and DAT tapes, i.e. telling that it is illegal to copy the contents
if the bit is set.

L 1 (2) Original
0 – Copy of original media
1 – Original media

The original bit indicates, if it is set, that the frame is
located on its original media.
M 2 (1,0) Emphasis
00 – none
01 – 50/15 ms
10 – reserved
11 – CCIT J.17

The emphasis indication is here to tell the decoder that the
file must be de-emphasized, ie the decoder must ‘re-equalize’
the sound after a Dolby-like noise supression. It is rarely
used.

C#中实现单实例

C#、设计模式 

public class SingletonDemo
{
    private static SingletonDemo theSingleton = null;
    private SingletonDemo() { }
    public static SingletonDemo Instance()
    {
        if (theSingleton == null)
        {
            theSingleton = new SingletonDemo();
        }
        return theSingleton;
    }
    static void Main(string[] args)
    {
        SingletonDemo s1 = SingletonDemo.Instance();
        SingletonDemo s2 = SingletonDemo.Instance();
        if (s1.Equals(s2))
        {
            Console.WriteLine("see, only one instance!");
        }
    }
}

更改flash builder 语言

Flex

安装目录里有个FlashBuilder.ini
打开

-clean
-nl
en_US
-startup
plugins/org.eclipse.equinox.launcher_1.0.201.R35x_v20090715.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.0.200.v20090519
-vmargs
-Xms256m
-Xmx512m
-XX:MaxPermSize=256m
-XX:PermSize=64m
-Djava.net.preferIPv4Stack=true
-Dorg.eclipse.equinox.p2.resolve

第三行是语言
可用的有：

de_DE
fr_FR
ja_JP
ru_RU
zh_CN
en_US

ActionScript访问WCF的svc WebService读取二进制数据

Flex

先写个wcf的svc服务
有个方法叫TestImage，返回一个图片的二进制数据
写好服务能用之后开始ActionScript的实现

先在build path里加入fiber.swc
我的fiber.swc路径是C:Program FilesAdobeAdobe Flash Builder 4pluginscom.adobe.flexbuilder.dcrad_4.0.0.272416dcradSwcs4.0libsfiber.swc

然后是代码 


package WebService

{
import com.adobe.fiber.core.model_internal;
import com.adobe.fiber.services.wrapper.WebServiceWrapper;
import flash.events.Event;
import flash.events.IOErrorEvent;
import flash.filesystem.File;
import flash.filesystem.FileMode;
import flash.filesystem.FileStream;
import flash.net.URLLoader;
import flash.net.URLRequest;
import flash.net.URLRequestMethod;
import flash.net.URLVariables;
import flash.utils.ByteArray;
import mx.rpc.AbstractOperation;
import mx.rpc.AsyncToken;
import mx.rpc.events.ResultEvent;
import mx.rpc.soap.mxml.WebService;
public class ImageTest extends WebServiceWrapper
{
  public function ImageTest()
  {
    _serviceControl = new WebService();
    //load wsdl
    _serviceControl.loadWSDL("http://192.168.0.2:8080/EpubService/Service1.svc?wsdl");
    model_internal::initialize();
    getImage();
  }
  public function getImage():void
  {
    var operation:AbstractOperation = _serviceControl.getOperation("TestImage");
    operation.addEventListener(ResultEvent.RESULT,onresult);
    operation.send();
  }
  private function onresult(e:ResultEvent):void
  {
    var imgByte:ByteArray = e.result as ByteArray;
    var f:File = File.documentsDirectory.resolvePath("test.jpg");
    var fs:FileStream = new FileStream();
    try
    {
      //open file in write mode
      fs.open(f,FileMode.WRITE);
      //write bytes from the byte array
      fs.writeBytes(imgByte);
      trace("create file: "+f.nativePath);
    }
    catch(e:Error)
    {
      trace(e.message);
    }
    finally
    {
      //close the file
      fs.close();
    }
    }
  }
}

输出：

create file: C:UsersQingDocumentstest.jpg

android写Xml文件

Android

废话少说，直接看代码

package cn.qing.xmltest;

import java.io.*;

import org.xmlpull.v1.XmlSerializer;

import android.app.Activity;

import android.os.*;

import android.util.*;

import android.widget.TextView;

public class wrXml extends Activity {

  /** Called when the activity is first created. */

  private String appDir;

  private String xmlFileName;

  StringBuilder sb;

  TextView tv;

  public wrXml(){

  }

  @Override

  public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    appDir = this.getApplicationContext().getFilesDir().getAbsolutePath();

    xmlFileName = appDir + "/test.xml";

    tv = new TextView(this);

    sb = new StringBuilder();

    writeXml();

    tv.setText(sb.toString());

    setContentView(tv);

  }

  private void writeXml() {

    File xmlFile = new File(xmlFileName);

    try {

      xmlFile.createNewFile();

    } catch (IOException e) {

      Log.e("IOException", "exception in createNewFile() method");

    }

    FileOutputStream fileos = null;

    try {

      fileos = new FileOutputStream(xmlFile);

    } catch (FileNotFoundException e) {

      Log.e("FileNotFoundException", "can't create FileOutputStream");

    }

    XmlSerializer serializer = Xml.newSerializer();

    try {

      serializer.setOutput(fileos, "UTF-8");

      serializer.startDocument(null, Boolean.valueOf(true));

      serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output",true);

      serializer.startTag(null, "root");

      serializer.startTag(null, "child1");

      serializer.endTag(null, "child1");

      serializer.startTag(null, "child2");

      serializer.attribute(null, "attribute", "value");

      serializer.endTag(null, "child2");

      serializer.startTag(null, "child3");

      serializer.text("some text inside child3");

      serializer.endTag(null, "child3");

      serializer.endTag(null, "root");

      serializer.endDocument();

      serializer.flush();

      fileos.close();

      sb.append("file has been created");

    } catch (Exception e) {

      Log.e("Exception", "error occurred while creating xml file");

      sb.append("Create file error");

    }

  }

}

.net mvc 中使用ActionFilterAttribute过滤器

.NET MVC

过滤器是mvc中常用的
在.net mvc 中直接继承和实现ActionFilterAttribute类就可以了
很简单
下面贴出一个例子
过滤器：


public class UseStopwatchAttribute : ActionFilterAttribute
{
  public override void OnActionExecuting(ActionExecutingContext filterContext)
  {
    Stopwatch stopWatch = new Stopwatch();
    stopWatch.Start();
    filterContext.Controller.ViewData["stopWatch"] = stopWatch;
  }
  public override void OnResultExecuting(ResultExecutingContext filterContext)
  {
    Stopwatch stopWatch = (Stopwatch)filterContext.Controller.ViewData["stopWatch"];
    stopWatch.Stop();
    Random r = new Random();
    filterContext.Controller.ViewData["elapsedTime"] = stopWatch.ElapsedMilliseconds
    + " milliseconds -   Rand  " + r.Next(1000).ToString();
  }
}

这的话这个过滤器就写好了
在使用的时候只要在controller上写上就行了


[UseStopwatch]
public class ProductsController : Controller
{
  //
  // GET: /Store/Products/
  public ActionResult List()
  {
    return View();
  }
  public ActionResult Details()
  {
    return View();
  }
  public ActionResult AddReview()
  {
    return View();
  }
}

C#中同步、异步读取进程输出信息

C#

1、异步的：

p.StartInfo.RedirectStandardError = true;
p.ErrorDataReceived += new DataReceivedEventHandler(OutputInfo);
p.Start();
p.BeginErrorReadLine();

private void OutputInfo(object sendProcess, DataReceivedEventArgs output){
  if (!String.IsNullOrEmpty(output.Data))
  {
    //处理方法...
  }
}

2、同步的

p.StartInfo.RedirectStandardError = true;
p.Start();
StreamReader sr = ffmpeg.StandardError;
p.WaitForExit();//之后就可以从sr里读了