如何从设备存储中正确删除列表视图项

Question

我正在开发笔记应用。我在每个列表视图项上实现了一个上下文菜单，弹出一个删除选项。选择删除选项后，会弹出一个警告对话框，询问用户是否要删除所选注释。我还有一个控制删除操作的Utilities类。这个问题是我无法为笔记实现正确的逻辑，因为所选的笔记项目不会消失。

Utilities.java

public class Utilities {

    /**
     * String extra for a note's filename
     */
    public static final String EXTRAS_NOTE_FILENAME = "EXTRAS_NOTE_FILENAME";
    public static final String FILE_EXTENSION = ".bin";
 public static boolean deleteFile(Context context, String fileName) {
        File dirFiles = context.getFilesDir();
        File file = new File(dirFiles, fileName);

        if(file.exists() && !file.isDirectory()) {
            return file.delete();
        }

        return false;
    }
}

主要活动

public boolean onContextItemSelected(MenuItem item) {
        AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
      final  Note mLoadedNote = (Note) mListNotes.getAdapter().getItem(info.position);
        mLoadedNote.getTitle();
        switch (item.getItemId()) {
                break;
            case R.id.delete:
                AlertDialog.Builder alertDialog = new AlertDialog.Builder(this)
                        .setTitle("Delete " +  mLoadedNote.getTitle())
                        .setMessage("are you sure?")
                .setPositiveButton("YES", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    mFileName = mListNotes.getAdapter().getItem(info.position) + (Utilities.EXTRAS_NOTE_FILENAME);
                    if(Utilities.deleteFile(getApplicationContext(), mFileName) ) {
                        Toast.makeText(MainActivity.this,  mLoadedNote.getTitle() + " is deleted", Toast.LENGTH_SHORT).show();

                    } else {
                        Toast.makeText(MainActivity.this,  "can not delete the note '" + mLoadedNote.getTitle() + "'", Toast.LENGTH_SHORT).show();
                    }

                }
                })
                    .setNegativeButton("NO", null); //do nothing on clicking NO button :P
                alertDialog.show();
        }
        return super.onContextItemSelected(item);
    }