android按行读取文件内容的几个方法

        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+"'");