Android/java 无法读取本地存储中的 .txt 文件

Question

所以我在本地存储中有一个 .txt 文件，它是一个简单的文本文件。文本基本上只是一系列的行。

我正在使用下面的代码尝试读取文本文件（我在调用此方法之前验证文件是否存在）。

public static String GetLocalMasterFileStream(String Operation) throws Exception {

//Get the text file
    File file = new File("sdcard/CM3/advices/advice_master.txt");
    if (file.canRead() == true) {System.out.println("-----Determined that file is readable");}

    //Read text from file
    StringBuilder text = new StringBuilder();
    BufferedReader br = new BufferedReader(new FileReader(file));
    String line;

    while ((line = br.readLine()) != null) {
        text.append(line);
        System.out.println("-----" + line);   //for producing test output
        text.append('\n');

    }
    br.close();
    System.out.print(text.toString());
    return text.toString();

}

代码在日志中产生

----确定文件可读 但那是文件数据不写入日志的唯一输出

我还尝试在 while 循环之前插入以下内容以尝试仅读取第一行

 line = br.readLine();
 System.out.println("-----" + line);

产生以下输出：

-----null

Answer 1

看看getExternalStorage

     File path = Environment.getExternalStorageDirectory();
     File file = new File(path, "textfile.txt");
//text file is copied in sdcard for example

Answer 2

尝试在文件路径 /sdcard/CM3/advices/advice_master.txt 中添加前导斜杠

 File file = new File("/sdcard/CM3/advices/advice_master.txt");

Answer 3

试试这个。只需将txt文件名作为参数传递...

public void readFromFile(String fileName){
    /*
    InputStream ips;
    ips = getClass().getResourceAsStream(fileName);

    //reading
    try{
        InputStreamReader ipsr = new InputStreamReader(ips);
        BufferedReader br = new BufferedReader(ipsr);
        String line;

        while ((line = br.readLine())!=null){
            //reading goes here ;)
        }
        br.close();
    }
    catch (Exception e){
        System.out.println(e.toString());
    }
   */
// or try this
File sdcard = Environment.getExternalStorageDirectory();

//Get the text file
File file = new File(sdcard,"file.txt");

//Read text from file
StringBuilder text = new StringBuilder();

try {
    BufferedReader br = new BufferedReader(new FileReader(file));
    String line;

    while ((line = br.readLine()) != null) {
        text.append(line);
        text.append('\n');
    }
    br.close();
}
catch (IOException e) {
    //You'll need to add proper error handling here
   }


}

Answer 4

让我完善我的答案。您可以尝试另一种方法来读取advice_master.txt 中的所有行，看看会发生什么。它确保可以读取所有文件内容。

Charset charset = Charset.forName("ISO-8859-1");
try {
  List<String> lines = Files.readAllLines(Paths.get(YOUR_PATH), charset);

  for (String line : lines) {
    System.out.println(line);
  }
} catch (IOException e) {
  System.out.println(e);
}