一直在尝试创建客户对话框，我从安卓网站复制了源代码。我工作了几件事，现在我真的卡住了。我不知道代码中的LoginFragment是什么：

...
public class start extends Activity{
Button buttonx;
final Context context = this;
LayoutInflater mInflater;

@Override
protected void onCreate (Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.menu);
}

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(context);
    // Get the layout inflater
    //LayoutInflater inflater = getActivity().getLayoutInflater();
    mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    // Inflate and set the layout for the dialog
    // Pass null as the parent view because its going in the dialog layout
    builder.setView(mInflater.inflate(R.layout.login, null))
            // Add action buttons
            .setPositiveButton(R.string.signin, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int id) {
                    // sign in the user ...
                }
            })
            .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {

                    LoginDialogFragment.this.getDialog().cancel();
                }
            });
    return builder.create();
}

当我//注解掉这一行时，它说@Override是不必要的，这并不能解决任何问题。