读取Log日志并打印到sdcard

 @SuppressLint("SimpleDateFormat")
     private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

     public static void LogWrite() {
         File file = new File(Constants.APP_PATH_LOG);
         if (!file.exists() || !file.isDirectory()) {
             file.mkdirs();
         }
         FileWriter fileWriter;
         StringBuilder log;
         try {
             Process process = Runtime.getRuntime().exec("logcat -d -v time");
             BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));

             log = new StringBuilder();
             String line;
             while ((line = bufferedReader.readLine()) != null) {
                 log.append(line);
                 log.append("\n");
             }
             fileWriter = new FileWriter(Environment.getExternalStorageDirectory() + "/" + “log-” + sdf.format(new Date()).substring(0, 10) + ".txt", true);
             fileWriter.write(log.toString());             fileWriter.flush();
             fileWriter.close();
             Runtime.getRuntime().exec("logcat -c");         } catch (IOException e) {

         } catch (OutOfMemoryError e) {

         }

     }