android - 无法打开 FileInputStream

Question

我在使用FileInputStream对象读取文件时遇到问题。我想打开的文件存在（我用同一个应用程序创建了它，我可以用我设备上的文件管理器看到它）。这就是方法：

public String readFile(String name) {
    try {
        FileInputStream fis;
        String res = "", read;
        File tmp = new File(directory, name);
        fis = new FileInputStream(tmp);

        InputStreamReader isr = new InputStreamReader(fis);
        BufferedReader buffered_reader = new BufferedReader(isr);

        read = buffered_reader.readLine();
        while (read != null) {
            res = res + read;
            Log.i("AAAAAAAAAAAAAAAAA", "letto"+read);
            read = buffered_reader.readLine();
        }
        isr.close();
        fis.close();
        return res;

    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    Log.i("AAAAAAAAAA", "Letto un cazzo");
    return null;
}

其中目录变量声明为：

private static File directory;

存储应用程序目录的静态对象文件。问题出在哪里？

Logcat 说

打开失败的enoent（没有这样的文件或目录）

在行

fis = new FileInputStream(tmp);

Answer 1

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Answer 2

open failed enoent (no such file or directory)

My suggestion is to fix it as

FileInputStream fis;
File tmp = new File(directory, name);
if (tmp.exists() && tmp.isFile()) {
   fis = new FileInputStream(tmp);
   InputStreamReader isr = new InputStreamReader(fis);
   BufferedReader buffered_reader = new BufferedReader(isr);
   // next lines ...
}
else {
  // error
}

So there is not way how to make it work. You need to pass correct FILE_PATH or it won't work. Also check if you have permission for reading and writing.

Answer 3

FileInputStream openFileInput(String nameOfFile)

打开与此上下文的应用程序包关联的私有文件以进行读取。

从阿皮。我已经使用它并且没有问题。