java - 创建文件并将其存储到外部存储

Question

这对你来说可能是一个简单的破解方法，但我不明白为什么这段代码不会在我的 Android 外部文件系统中创建一个新文件？目录已正确创建，但文件未正确创建，而是我收到 java.io.FileNotFoundException:/mnt/sdcard/Mydir/MyFile，任何人都可以看到问题是什么，因为我看不到它吗？

        //Generate a unique filename using date and time
    String fileName = "myFile_"+formatter_file_name.format(today)+".txt";

    //Get path to root
    String root = Environment.getExternalStorageDirectory().toString();

    //Create(if not exists) directory in root in which to store the reports 
    File myDir = new File(root + "/myDir");   
    myDir.mkdirs();

    //Create report file object
    File file = new File (myDir, fileName);

    //If file already exists delete id(this should not be able to happen)
    if (file.exists()) file.delete(); 

    try {
        FileOutputStream fout = new FileOutputStream(file);
        OutputStreamWriter osw = new OutputStreamWriter(fout); 

        // Write the string to the file
        osw.write("TEST STRING");

        //Ensure that everything has been written to the file and close 
        osw.flush();
        osw.close();
    } catch (Exception e) {
           e.printStackTrace();
    }    

我的 list 中有正确的权限，我将插入一个检查以查看外部存储是否可用于写入，但我不认为这是问题...

Answer 1

试试这个

try {
   File root = Environment.getExternalStorageDirectory();
   File myFile = new File(root +"/textfile.txt");
   myFile.createNewFile();

   FileOutputStream fOut = new FileOutputStream(myFile);
   OutputStreamWriter myOutWriter = 
         new OutputStreamWriter(fOut);
   myOutWriter.append("String entered in file");

   myOutWriter.close();
   fOut.close();
} catch (Exception e) {
   Toast.makeText(getBaseContext(), e.getMessage(),Toast.LENGTH_SHORT).show();

}