常用的android权限配置和常用工具代码

1、访问权限的配置

<!-- 访问internet权限 --><uses-permission android:name="android.permission.INTERNET"/><!-- 在SDCard中创建与删除文件权限 --><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/><!-- 往SDCard写入数据权限 --><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

2、MD5加密

public class MD5 {public static String getMD5(String content) {try {MessageDigest digest = MessageDigest.getInstance("MD5");digest.update(content.getBytes());return getHashString(digest);} catch (NoSuchAlgorithmException e) {e.printStackTrace();}return null;}  private static String getHashString(MessageDigest digest) {      StringBuilder builder = new StringBuilder();      for (byte b : digest.digest()) {          builder.append(Integer.toHexString((b >> 4) & 0xf));          builder.append(Integer.toHexString(b & 0xf));      }      return builder.toString();  }}

3、XmlPullParser解析xml文件返回List对象

/** 根据提供的URL，得到HttpURLConnection的连接，设置超时时间和请求方式* 使用XMLPullParser解析请求的输入流,循环解析xml，直到文档的结尾* <?xml version="1.0" encoding="UTF-8"?>  <topics>    <topic id="1">     <title>西安大雁塔01</title>     <image src="http://192.168.173.1:8081/mysap/images/0101.jpg"/>   </topic> </topics>*/public List<Topic> getContacts() throws Exception{    String dataURL = "http://192.168.173.1:8081/mysap/datafile/topic01.xml";    HttpURLConnection conn = (HttpURLConnection)new URL(dataURL).openConnection();    conn.setConnectTimeout(5000);    conn.setRequestMethod("GET");    if(conn.getResponseCode() == 200){      InputStream inputStream = conn.getInputStream();      String inputEncoding = "UTF-8";      XmlPullParser xmlParser = Xml.newPullParser();      xmlParser.setInput(inputStream, inputEncoding);      List<Topic> topicList = new ArrayList<Topic>();      int eventType = xmlParser.getEventType();      String tagName = null;      Topic topic = null;      while(eventType != XmlPullParser.END_DOCUMENT){  tagName = xmlParser.getName();  switch(eventType){   case XmlPullParser.START_TAG:      if("topic".equals(tagName)){         topic = new Topic();         topic.id = new Integer(xmlParser.getAttributeValue(0));      }else if("title".equals(tagName)){         topic.title = xmlParser.nextText();      }else if("image".equals(tagName)){         topic.imageSrc = xmlParser.getAttributeValue(0);      }      break;   case XmlPullParser.END_TAG:      if("topic".equals(tagName)){topicList.add(topic);topic = null;              }      break;   }   eventType = xmlParser.next();}return topicList;     }     return null;}

4、从网络上获取文件，存储在指定的缓存目录下

/** * 先把网络文件的fileUri进行MD5加密处理，然后生产对应的文件（后缀名不变） * 先从缓存目录下查询是否存在该文件，如果不存在则再次获取，直接从缓存中获取 * 否则把网络文件缓存到本地 * @param fileUri * @param cacheDir * @return * @throws Exception */public Uri getImage(String fileUri, File cacheDir) throws Exception{String tempPath = MD5.getMD5(fileUri) + fileUri.substring(fileUri.lastIndexOf("."));File localFile = new File(cacheDir, tempPath);if(localFile.exists()){return Uri.fromFile(localFile);}else{HttpURLConnection conn = (HttpURLConnection)new URL(fileUri).openConnection();conn.setConnectTimeout(5000);conn.setRequestMethod("GET");if(conn.getResponseCode() == 200){FileOutputStream outStream = new FileOutputStream(localFile);InputStream inputStream = conn.getInputStream();byte[] buffer = new byte[1024];int len = 0;while( (len = inputStream.read(buffer)) != -1){outStream.write(buffer, 0, len);}inputStream.close();outStream.close();return Uri.fromFile(localFile);}}return null;}

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