import java.io.FileInputStream; void readFileOnLine(){ String strFileName = "Filename.txt"; FileInputStream fis = openFileInput(strFileName); StringBuffer sBuffer = new StringBuffer(); DataInputStream dataIO = new DataInputStream(fis); String strLine = null; while((strLine =  dataIO.readLine()) != null) {     sBuffer.append(strLine + “\n"); } dataIO.close(); fis.close(); }

//读取文本文件中的内容     public static String ReadTxtFile(String strFilePath)     {         String path = strFilePath;         String content = ""; //文件内容字符串             //打开文件             File file = new File(path);             //如果path是传递过来的参数，可以做一个非目录的判断             if (file.isDirectory())             {                 Log.d("TestFile", "The File doesn't not exist.");             }             else             {                 try {                     InputStream instream = new FileInputStream(file);                     if (instream != null)                     {                         InputStreamReader inputreader = new InputStreamReader(instream);                         BufferedReader buffreader = new BufferedReader(inputreader);                         String line;                         //分行读取                         while (( line = buffreader.readLine()) != null) {                             content += line + "\n";                         }                                        instream.close();                     }                 }                 catch (java.io.FileNotFoundException e)                 {                     Log.d("TestFile", "The File doesn't not exist.");                 }                 catch (IOException e)                 {                      Log.d("TestFile", e.getMessage());                 }             }             return content;     }

//首先定义一个数据类型，用于保存读取文件的内容 class WeightRecord {         String timestamp;         float weight;         public WeightRecord(String timestamp, float weight) {             this.timestamp = timestamp;             this.weight = weight;                     }     }     //开始读取  private WeightRecord[] readLog() throws Exception {         ArrayList<WeightRecord> result = new ArrayList<WeightRecord>();         File root = Environment.getExternalStorageDirectory();         if (root == null)             throw new Exception("external storage dir not found");         //首先找到文件         File weightLogFile = new File(root,WeightService.LOGFILEPATH);         if (!weightLogFile.exists())             throw new Exception("logfile '"+weightLogFile+"' not found");         if (!weightLogFile.canRead())             throw new Exception("logfile '"+weightLogFile+"' not readable");         long modtime = weightLogFile.lastModified();         if (modtime == lastRecordFileModtime)             return lastLog;         // file exists, is readable, and is recently modified -- reread it.         lastRecordFileModtime = modtime;         // 然后将文件转化成字节流读取         FileReader reader = new FileReader(weightLogFile);         BufferedReader in = new BufferedReader(reader);         long currentTime = -1;         //逐行读取         String line = in.readLine();         while (line != null) {             WeightRecord rec = parseLine(line);             if (rec == null)                 Log.e(TAG, "could not parse line: '"+line+"'");             else if (Long.parseLong(rec.timestamp) < currentTime)                 Log.e(TAG, "ignoring '"+line+"' since it's older than prev log line");             else {                 Log.i(TAG,"line="+rec);                 result.add(rec);                 currentTime = Long.parseLong(rec.timestamp);             }             line = in.readLine();         }         in.close();         lastLog = (WeightRecord[]) result.toArray(new WeightRecord[result.size()]);         return lastLog;     }     //解析每一行     private WeightRecord parseLine(String line) {         if (line == null)             return null;         String[] split = line.split("[;]");         if (split.length < 2)             return null;         if (split[0].equals("Date"))             return null;         try {             String timestamp =(split[0]);             float weight =  Float.parseFloat(split[1]) ;             return new WeightRecord(timestamp,weight);         }         catch (Exception e) {             Log.e(TAG,"Invalid format in line '"+line+"'");             return null;         }     }

public boolean logWeight(Intent batteryChangeIntent) {             Log.i(TAG, "logBattery");             if (batteryChangeIntent == null)                 return false;             try {                 FileWriter out = null;                 if (mWeightLogFile != null) {                     try {                         out = new FileWriter(mWeightLogFile, true);                     }                     catch (Exception e) {}                 }                 if (out == null) {                     File root = Environment.getExternalStorageDirectory();                     if (root == null)                         throw new Exception("external storage dir not found");                     mWeightLogFile = new File(root,WeightService.LOGFILEPATH);                     boolean fileExists = mWeightLogFile.exists();                     if (!fileExists) {                         if(!mWeightLogFile.getParentFile().mkdirs()){                             Toast.makeText(this, "create file failed", Toast.LENGTH_SHORT).show();                         }                         mWeightLogFile.createNewFile();                     }                     if (!mWeightLogFile.exists()) {                         Log.i(TAG, "out = null");                         throw new Exception("creation of file '"+mWeightLogFile.toString()+"' failed");                     }                     if (!mWeightLogFile.canWrite())                         throw new Exception("file '"+mWeightLogFile.toString()+"' is not writable");                     out = new FileWriter(mWeightLogFile, true);                     if (!fileExists) {                         String header = createHeadLine();                         out.write(header);                         out.write('\n');                     }                 }                 Log.i(TAG, "out != null");                 String extras = createBatteryInfoLine(batteryChangeIntent);                 out.write(extras);                 out.write('\n');                 out.flush();                 out.close();                 return true;             } catch (Exception e) {                 Log.e(TAG,e.getMessage(),e);                 return false;             }         }