android Dialog的确定按钮点击后不取消对话框

	private Dialog modifyNickName() {
		LayoutInflater factory = LayoutInflater.from(this);
		final View textEntryView = factory.inflate(
				R.layout.alert_change_nickname, null);
		return new AlertDialog.Builder(My.this).setIcon(
				R.drawable.alert_dialog_icon).setTitle(
				getString(R.string.change_nickname)).setView(textEntryView)
				.setPositiveButton(R.string.alert_dialog_setting,
						new DialogInterface.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int whichButton) {
								EditText editNickNameText = (EditText) textEntryView
										.findViewById(R.id.nickname);
								String nickName = editNickNameText.getText()
										.toString();
								Toast.makeText(
										My.this,
										nickName,
										Toast.LENGTH_SHORT).show();
								Field field;
								try {
									field = dialog.getClass()
									.getSuperclass().getDeclaredField(
									"mShowing");
									field.setAccessible(true);	
									if(nickName == null || nickName.equals(""))
									{
										field.set(dialog, false);	
									}else
									{
										field.set(dialog, true);	
									}
									dialog.dismiss();
								} catch (SecurityException e) {
									e.printStackTrace();
								} catch (NoSuchFieldException e) {
									e.printStackTrace();
								} catch (IllegalArgumentException e) {
									e.printStackTrace();
								} catch (IllegalAccessException e) {
									e.printStackTrace();
								}
							}
						}).setNegativeButton(R.string.alert_dialog_cancel,
						new DialogInterface.OnClickListener() {
							public void onClick(DialogInterface dialog,
									int whichButton) {
								Field field;
								try {
									field = dialog.getClass()
									.getSuperclass().getDeclaredField(
									"mShowing");
									field.setAccessible(true);	
									field.set(dialog, true);
									dialog.dismiss();
								} catch (SecurityException e) {
									e.printStackTrace();
								} catch (NoSuchFieldException e) {
									e.printStackTrace();
								} catch (IllegalArgumentException e) {
									e.printStackTrace();
								} catch (IllegalAccessException e) {
									e.printStackTrace();
								}
							}
						}).create();
	}