創建並存儲文件到外部存儲

Question

這可能是一個簡單的破解，但我不明白爲什麼這段代碼不會導致在我的Android外部文件系統中創建一個新文件？該目錄正確創建，但不是文件，而是我得到一個java.io.FileNotFoundException：/ mnt/sdcard/Mydir/MyFile，任何人都可以看到問題是什麼原因，我不能看到它嗎？

 //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(); 
    }  

我有正確的權限在我的表現，我將插入一個檢查，看看外部存儲空間可用於寫，但我dont't認爲這就是問題所在......

Answer 1

試試這個

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(); 

}