java - 无法从文本文件中读取行

Question

我有这样的方法:

    public int getIncrement() {

    String extractFolder = "/mnt/sdcard/MyFolder";
    boolean newFolder = new File(extractFolder).mkdir();
    int counter = 0; 

    try {
        File root = new File(extractFolder); 
        if (root.canWrite()){
            File gpxfile = new File(root, "gpxfile.txt");
            FileWriter gpxwriter = new FileWriter(gpxfile);
            BufferedWriter out = new BufferedWriter(gpxwriter);

            Scanner scanner = new Scanner(new FileInputStream(gpxfile.getAbsolutePath()), "UTF-8");
            Log.i("PATH: ", extractFolder + "/gpxfile.txt");

           while(scanner.hasNextLine()) {
               String inc = scanner.nextLine(); 
               counter = Integer.parseInt(inc);
               Log.i("INSIDE WHILE: ", Integer.toString(counter)); 
           }
            counter++;
            out.write(Integer.toString(counter));
            out.close();
        }
    } catch (IOException e) {
        Log.e("GEN_PCN: ", "Could not write file " + e.getMessage());
    }
    return counter;  
}

我想要完成的是返回此文件的内容，并将 integer 递增 1。但似乎我无法进入 while循环，因为 LogCat 没有打印出任何东西。是的，确保路径是正确的。

Answer 1

我猜 FileWriter gpxwriter 的构造函数在创建 Scanner 时已经清空了文件，所以文件是空的并且 hasNextLine 返回 false。为什么要读取文件时打开文件进行写入？