//读写文件函数调用 writeFileData(filename,datas);String result=readFileData(filename);Toast.makeText(Main2Activity.this,result.getClass().toString(),Toast.LENGTH_SHORT).show();

下面是读写代码的实现：

//文件写入    public void writeFileData(String filename, String content){        try {            FileOutputStream fos = this.openFileOutput(filename, MODE_PRIVATE);//获得FileOutputStream            //将要写入的字符串转换为byte数组            byte[]  bytes = content.getBytes();            fos.write(bytes);//将byte数组写入文件            fos.close();//关闭文件输出流        } catch (Exception e) {            e.printStackTrace();        }    }    //文件读取    public String readFileData(String fileName){        String result="";        try{            FileInputStream fis = openFileInput(fileName);            //获取文件长度            int lenght = fis.available();            byte[] buffer = new byte[lenght];            fis.read(buffer);            //将byte数组转换成指定格式的字符串            result = new String(buffer, "UTF-8");        } catch (Exception e) {            e.printStackTrace();        }        return  result;    }