如何保存（让微调器记住）微调器下拉列表中选定项目的位置

【问题标题】：How do I save (make the spinner remember) the position of a selected item on the spinner drop down如何保存（让微调器记住）微调器下拉列表中选定项目的位置
【发布时间】：2014-08-21 20:38:16
【问题描述】：

我需要将所选项目保存在微调器中。目前我有 3 个部分，topnews/mynews 和breakviews。每个部分都有一个由项目组成的动态列表，比如 topnews 有 europe/asia/germany/frontnews 等。在侧面我有一个菜单按钮，我可以从中添加或删除要在这 3 个类别中显示的项目。现在，每次我在微调器中选择一个项目时说“德国”，然后单击菜单按钮并添加或删除德国上方或下方的任何项目，微调器上的位置也会移动到先前选择的项目或下一个物品。无论通过菜单按钮从菜单列表中添加或删除的项目如何，我如何让微调器记住最后一次选择。

我在 sharedpreferencesmanager.java 中添加了以下代码：

private static final String PROPERTY_NEWS_INDEX = "newsindex";
public void savenewsselectedindex(int selectedindex) {
        mSharedPreferences.edit().putInt(PROPERTY_NEWS_INDEX, selectedindex).apply();
        Log.d("newsdash", "");
    }

    public int getnewsselectedindex(){
        return mSharedPreferences.getInt(PROPERTY_NEWS_INDEX, 0);
    }

以下是我的片段类：（我还没有对它应用sharedpreferences，不知道在哪里添加它以及如何添加它，无论是位置参数还是显示的字符串：

public class NewsCategoriesFragment extends AbsLoaderFragment implements OnItemSelectedListener, OnClickListener, OnMenuItemClickedListener,Dialog.OnDismissListener {

    public static final String TAG_NEWS_CATEGORIES_FRAGMENT = "NewsCategoriesFragment";
    private static int mSelectedCategoryCodePosition;

    private NewsCategorySpinnerAdapter mCategoryAdapter;

    private List<AdapterRow> mTopNewsRows;
    private List<AdapterRow> mMyNewsRows;
    private List<AdapterRow> mBreakingViewsRows;
    private List<AdapterRow> mMostReadNewsRows;

    private boolean mHasNonMyNewsCategoriesLoaded;
    private boolean mHasMyNewsCategoriesLoaded;

    private String mSelectedCategory;
    private boolean mFirstTimeLoadingMyNews;
    private boolean mFirstTimeLoadingNonMyNews;
    private MenuHelper mMenuHelper;
    private final ArrayList<String> mMenuItems = new ArrayList<String>();
    private HeaderView headerView;

    private static class MenuItems{
        final static String MANAGE_NEWS_CATEGORIES = Application.getAppResources().getString(R.string.news_menu_manage);
        final static String NEWS_PREFERENCES = Application.getAppResources().getString(R.string.news_menu_preferences);
        static final int MANAGE_NEWS_CATEGORIES_POSITION = 0;
        static final int NEWS_PREFERENCES_POSITION = 1;
    }

    public static NewsCategoriesFragment newInstance(final FragmentManager manager, final int categoryCodePosition) {
        final NewsCategoriesFragment fragment = new NewsCategoriesFragment();
        mSelectedCategoryCodePosition = categoryCodePosition;
        final FragmentInfo fragmentInfo = new FragmentInfo(TransactionMethods.ADD, R.id.header_container);
        fragmentInfo.setFragmentTag(TAG_NEWS_CATEGORIES_FRAGMENT);
        fragmentInfo.doNotAddToBackStack();
        fragmentInfo.setAnimation(R.anim.no_animation, R.anim.no_animation);
        fragmentInfo.setPopAnimation(R.anim.no_animation, R.anim.no_animation);
        FragmentStackManager.getInstance().transitionFragment(manager, fragment, fragmentInfo);
        return fragment;
    }

    @Override
    public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) {
        final View view = inflater.inflate(R.layout.fragment_news_categories, container, false);
        headerView = (HeaderView) view.findViewById(R.id.news_categories_container);
        headerView.setContextMenuOnClickListener(this);
        mMyNewsLoader.onCreate(getActivity());

        createMenu();
        return view;
    }

    private void createMenu() {
        mMenuItems.add(MenuItems.MANAGE_NEWS_CATEGORIES);
        mMenuItems.add(MenuItems.NEWS_PREFERENCES);

        mMenuHelper = new MenuHelper(getActivity(), mMenuItems,this,this);
    }

    @Override
    public void onViewCreated(final View view, final Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        mFirstTimeLoadingNonMyNews = true;
        mFirstTimeLoadingMyNews = true;
        mMyNewsLoader.initLoader();
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        mMyNewsLoader.onDestroy();
    }

    @Override
    public Uri onCreateContentUri() {
        final Uri baseUri = NewsContentProvider.USER_CATEGORIES_URI;
        final Builder builder = baseUri.buildUpon().appendQueryParameter(UserCategory.QueryParams.SHORT_LIST, String.valueOf(true));
        return builder.build();
    }

    @Override
    public void onCursorLoaded(final Uri uri, final Cursor cursor) {
        Log.d("CategoryIssue", "News - CursorLoaded");
        if (!mFirstTimeLoadingNonMyNews || cursor.getCount() > 0 || !isOperationExecuting()) {
            Log.d("CategoryIssue", "News - CursorLoaded with count " + cursor.getCount());
            PrecacheManager.getInstance().saveNonMyNewsCategoriesForCaching(cursor, mSelectedCategory);

            populateCategoryRows(cursor);

            mHasNonMyNewsCategoriesLoaded = true;
            if (mHasMyNewsCategoriesLoaded) {
                Log.d("CategoryIssue", "News - CursorLoaded showing results");
                showResults(uri);
            }
        }

        if (mFirstTimeLoadingNonMyNews) {
            mFirstTimeLoadingNonMyNews = false;
        }
    }

    @Override
    public void onOperationError(Uri uri, RestError error) {
        super.onOperationError(uri, error);
        mHasNonMyNewsCategoriesLoaded = true;
        if (mHasMyNewsCategoriesLoaded) {
            showResults(uri);
        }
    }

    private void updateCategorySpinner() {
        mCategoryAdapter.updateTopNewsRows(mTopNewsRows);
        mCategoryAdapter.updateBreakinViewsRows(mBreakingViewsRows);

        if (mMyNewsRows == null || mMyNewsRows.size() <= 1) {
            mCategoryAdapter.removeMyNews();
        } else {
            mCategoryAdapter.updateMyNewsRows(mMyNewsRows);
        }
    }

    private void initCategorySpinner() {
        mCategoryAdapter = new NewsCategorySpinnerAdapter(getActivity(), mTopNewsRows, mBreakingViewsRows, mMyNewsRows,mMostReadNewsRows);
        headerView.setSpinnerAdapter(mCategoryAdapter);
        headerView.setSpinnerOnItemSelectedListener(this);
        headerView.setSpinnerSelectedItemPosition(mSelectedCategoryCodePosition);
    }

    @Override
    public void showResults(final Uri uri) {
        LayoutUtils.showResults(getView(), headerView.getSpinnerId());
        if (mCategoryAdapter == null) {
            Log.d("CategoryIssue", "init spinner");
            initCategorySpinner();
        } else {
            Log.d("CategoryIssue", "update spinner");
            updateCategorySpinner();
        }
    }

    @Override
    public void showNoResults(final Uri uri) {
        LayoutUtils.showNoResult(getView(), headerView.getSpinnerId());
    }

    @Override
    public void onClick(final View view) {
        switch (view.getId()) {
            case R.id.context_menu_button:
                final int actionBarHeight = getActivity().findViewById(R.id.title_main_container).getHeight();
                mMenuHelper.showMenu(getView().getBottom() + actionBarHeight, Gravity.RIGHT);
                BangoHelper.eventSettings();
                if (headerView.isSelected()) {
                    headerView.setSelected(false);
                    Log.i("ImageButtonCheck", "Button is not selected anymore");
                } else {
                    headerView.setSelected(true);
                    Log.i("ImageButtonCheck", "Button is in selected state");
                }
                break;
            default:
                break;
        }
    }

    private void populateCategoryRows(final Cursor cursor) {
        final Resources resources = getView().getResources();

        mTopNewsRows = new ArrayList<AdapterRow>();
        String categoryTitle = resources.getString(R.string.title_top_news);
        mTopNewsRows.add(new CategoryHeader(categoryTitle));

        mBreakingViewsRows = new ArrayList<AdapterRow>();
        categoryTitle = resources.getString(R.string.title_breakingviews);
        if(SharedPreferencesManager.getInstance().isLiteUser()){
        }else{
        mBreakingViewsRows.add(new CategoryHeader(categoryTitle));
        }

        cursor.moveToPosition(-1);

        if(Locale.getDefault().toString().equals("ja_JP")){
            final String categoryName = Application.getAppResources().getString(R.string.news_category_constant_japanese);
            final String categoryCode = "urn:newsml:reuters.com:20090527:SPDOC_1323242720091";
            mTopNewsRows.add(new SpinnerCategoryRow(categoryName, categoryCode, Type.TOP_NEWS));
        } else if(Locale.getDefault().toString().equals("zh_CN")){
            final String categoryName = Application.getAppResources().getString(R.string.news_category_constant_chinese);
            final String categoryCode = "urn:newsml:reuters.com:20100623:SPDOC_1331612320101";
            mTopNewsRows.add(new SpinnerCategoryRow(categoryName, categoryCode, Type.TOP_NEWS));
        }

        while (cursor.moveToNext()) {
            final String navGroup = cursor.getString(cursor.getColumnIndex(NewsCategory.Columns.NAVIGATION_GROUP));
            final String categoryName = cursor.getString(cursor.getColumnIndex(NewsCategory.Columns.NAME));
            final String categoryCode = cursor.getString(cursor.getColumnIndex(NewsCategory.Columns.CODE));

            if (NewsCategory.Constants.BREAKINGVIEWS.equals(navGroup)) {
                mBreakingViewsRows.add(new SpinnerCategoryRow(categoryName, categoryCode, Type.BREAKINGVIEWS));
            } else {
                mTopNewsRows.add(new SpinnerCategoryRow(categoryName, categoryCode, Type.TOP_NEWS));
            }
        }
    }

    private final ContentLoader mMyNewsLoader = new ContentLoader() {

        @Override
        public Uri onCreateContentUri() {
            final Builder builder = PreferencesContentProvider.MY_NEWS_CATEGORIES_CONTENT_URI.buildUpon();
            builder.appendQueryParameter(MyNewsCategory.QueryParams.SELECTED_ONLY, String.valueOf(true));
            return builder.build();
        };

        @Override
        public void onOperationError(final Uri uri, final RestError error) {
            super.onOperationError(uri, error);
            mHasMyNewsCategoriesLoaded = true;

            if (mHasNonMyNewsCategoriesLoaded) {
                showResults(uri);
            }
        };

        @Override
        public void onCursorLoaded(final Uri uri, final Cursor cursor) {
            if (!mFirstTimeLoadingMyNews || cursor.getCount() > 0 || !isOperationExecuting()) {
                PrecacheManager.getInstance().saveMyNewsCategoriesForCaching(cursor, mSelectedCategory);
                populateMyNewsCateogryRows(cursor);

                mHasMyNewsCategoriesLoaded = true;
                if (mHasNonMyNewsCategoriesLoaded) {
                    showResults(uri);
                }

                if (cursor.getCount() == 0) {
                    if (mCategoryAdapter != null) {
                        mCategoryAdapter.removeMyNews();
                    }
                }
            }

            if (mFirstTimeLoadingMyNews) {
                mFirstTimeLoadingMyNews = false;
            }
        }

        private void populateMyNewsCateogryRows(final Cursor cursor) {
            mMyNewsRows = new ArrayList<AdapterRow>();
            mMyNewsRows.add(new CategoryHeader(getView().getResources().getString(R.string.title_my_news)));
            cursor.moveToPosition(-1);

            while (cursor.moveToNext()) {
                final String categoryCode = cursor.getString(cursor.getColumnIndex(MyNewsCategory.Columns.FILE_NAME));
                final String categoryName = cursor.getString(cursor.getColumnIndex(MyNewsCategory.Columns.NAME));
                mMyNewsRows.add(new SpinnerCategoryRow(categoryName, categoryCode, Type.MY_NEWS));
            }
        };
    };

    @Override
    public void onMenuItemClicked(final int position) {
        switch (position) {
        case MenuItems.MANAGE_NEWS_CATEGORIES_POSITION:
            ManageNewsCategoriesActivity.newInstance(getActivity());
            break;
        case MenuItems.NEWS_PREFERENCES_POSITION:
            NewsPreferencesActivity.newInstance(getActivity());
            break;
        default:
            break;
        }
        headerView.setSelected(false);
        mMenuHelper.hideMenu();
    }

    @Override
    public void onItemSelected(IcsAdapterView<?> parent, View view, int position, long id) {
        final SpinnerCategoryRow item = (SpinnerCategoryRow) parent.getItemAtPosition(position);

        final NewsFragment parentFragment = (NewsFragment) getParentFragment();

        mSelectedCategory = item.getCategoryCode();

        if (item.getCategoryType() == Type.MY_NEWS) {
            parentFragment.onMyNewsSelected(mSelectedCategory);
            parentFragment.onCategoryPositionSelected(position);
        } else {
            parentFragment.onCategorySelected(mSelectedCategory);
            parentFragment.onCategoryPositionSelected(position);
        }
        parentFragment.dismissPullToRefresh();      
    }
    @Override
    public void onDismiss(DialogInterface dialog) {
        headerView.setSelected(false);
    }
    @Override
    public void onNothingSelected(IcsAdapterView<?> parent) {
    }
}

另外，请告诉我是否应该添加适配器和活动的代码以进一步解释它，但我认为只有片段就足够了，但我可能错了

添加微调器：

public class NewsCategorySpinnerAdapter extends CustomRowAdapter<AdapterRow> {

    private List<AdapterRow> mTopNewsRows;
    private List<AdapterRow> mBreakingViewsRows;
    private List<AdapterRow> mMyNewsRows;

    private List<AdapterRow> mRenderList;

    public NewsCategorySpinnerAdapter(final Context context, final List<AdapterRow> topNewsRows, final List<AdapterRow> breakingViewsRows, final List<AdapterRow> myNewsRows) {
        super(context);

        mTopNewsRows = topNewsRows;
        mBreakingViewsRows = breakingViewsRows;
        mMyNewsRows = myNewsRows;

        mRenderList = new ArrayList<AdapterRow>();
        mRenderList.addAll(topNewsRows);
        mRenderList.addAll(breakingViewsRows);
        //mRenderList.addAll(myNewsRows);

        if (myNewsRows != null && myNewsRows.size() > 0) {
            mRenderList.addAll(myNewsRows);
        }

        if (mostReadNewsRows != null && mostReadNewsRows.size() > 0) {
            mRenderList.addAll(mostReadNewsRows);
        }
    }

    @Override
    protected void setEntries(final List<AdapterRow> renderList) {
        mRenderList = renderList;
    }

    @Override
    protected List<AdapterRow> getEntries() {
        return mRenderList;
    }

    @Override
    public View getDropDownView(final int position, final View convertView, final ViewGroup parent) {
        return getEntries().get(position).getDropDownView(mContext, convertView);
    }

    public void updateTopNewsRows(final List<AdapterRow> topNewsRows) {
        if (mTopNewsRows != null) {
            mTopNewsRows = topNewsRows;
            recontructRenderList();
        } else {
            getEntries().addAll(topNewsRows);
        }

        notifyDataSetChanged();
    }

    public void updateBreakinViewsRows(final List<AdapterRow> breakingViewsRows) {
        if (mBreakingViewsRows != null) {
            mBreakingViewsRows = breakingViewsRows;
            recontructRenderList();
        } else {
            getEntries().addAll(breakingViewsRows);
        }

        notifyDataSetChanged();
    }

    public void updateMyNewsRows(final List<AdapterRow> myNewsRows) {
        if (mMyNewsRows != null) {
            mMyNewsRows = myNewsRows;
            recontructRenderList();
        } else {
            getEntries().addAll(myNewsRows);
        }

        notifyDataSetChanged();
    }




    private void recontructRenderList() {
        getEntries().clear();

        addSection(mTopNewsRows);
        addSection(mBreakingViewsRows);
        addSection(mMyNewsRows);
    }

    private void addSection(final List<AdapterRow> section) {
        if (section != null && !section.isEmpty()) {
            getEntries().addAll(section);
        }
    }

    public void removeMyNews() {
        if (ArrayUtils.isNotEmpty(mMyNewsRows)) {
            mRenderList.removeAll(mMyNewsRows);
            mMyNewsRows = null;
            notifyDataSetChanged();
        }
    }


    }

}

【问题讨论】：

  • 为什么不保存值而不是位置？
  • 我该怎么做？你能解释一下我的代码吗？

标签： java android android-intent android-activity android-fragments


【解决方案1】：

在 onItemSelected() 方法中使用此代码并保存所选值的微调器位置：

int Choice = spinner.getSelectedItemPosition();
SharedPreferences sharedPref = getSharedPreferences("FileName",0);
SharedPreferences.Editor prefEditor = sharedPref.edit();
prefEditor.putInt("spinnerChoice",Choice);
prefEditor.commit();

从 sharedPreferences 中设置选项：

SharedPreferences sharedPref = getSharedPreferences("FileName",MODE_PRIVATE);
int spinnerValue = sharedPref.getInt("spinnerChoice",-1);
if(spinnerValue != -1) 
spinner.setSelection(spinnerValue);

【讨论】：

  • 我认为你不需要保存位置。相反，您可以保存选定的文本。因此，如果您删除或添加，那么您仍然可以在其文本中获得正确的项目。但是如果您保存位置，例如您在选定项目之前删除项目，那么该位置将得到错误/错误，但如果您保存选定项目的文本，那么您将获得正确的项目。希望你能明白我的意思。
【解决方案2】：

使用它来获取选定的字符串：

String text = spinner.getSelectedItem().toString();

这会在一个项目被删除后再次设置微调器：

ArrayAdapter myAdap = (ArrayAdapter) spinner.getAdapter();
int spinnerPosition = myAdap.getPosition(text);
spinner.setSelection(spinnerPosition);

【讨论】：

  • 我不应该使用 sharedprefs 让它记住我的选择吗？
  • 这并不能解决这个问题：“现在，每次我在微调器中选择一个项目时都说“德国”，然后单击菜单按钮并添加或删除德国上方或下方的任何项目，微调器上的位置也会移动到先前选择的项目或下一个项目。”
  • 项目没有被删除，它只是根据所做的选择在微调器中前后移动一步。我试过这个代码： mCategoryAdapter.getItem(mSelectedcategory) 考虑到我设置 mSelectedcategory AS item.getCategoryName().toString();我可能做错了，你能检查一下 showResults 中调用的 onItemSelected 和 updateCategorySpinner 函数，更新发生在哪里并最终影响微调器，并解释一下吗？谢谢！
【解决方案3】：

您可以将所选项目文本保存在 sharedpreference 上（您知道怎么做，所以我不再赘述）。然后在您单击添加按钮并将新字符串添加到您的数组后调用：

spinner.setSelection(yourArrayList.indexOf("yourPreviusNameThatRetriveFromSharedPreference"));

【讨论】：

  • 这个微调器是什么？关于我的代码，它是定义为 spinnercategoryrow 的项目吗？你能解释一下我的代码吗？
  • 你在哪里定义你的微调器？（我在你的代码中没有找到它）
  • 请检查适配器代码，我在其中定义微调器适配器行
【解决方案4】：

您可以将上次选择的位置保存在 SharedPreference 中，并且当用户单击微调器时，您可以设置 spinner.setSelection(position)。它保存在您的 SharedPreference 中。这是解决此问题的唯一解决方案。

【讨论】：

  • 你能解释一下我的代码吗？我试图这样做，但它没有改变任何东西，我在哪里调用 get 方法以及我在哪里保存位置
  • 我要做的是保存 itemId 而不是索引，每当您恢复屏幕时，遍历列表获取项目并比较 id，如果相等，则选择该索引。
  • 您能否将我的代码作为单独的答案进行解释，这会很有帮助。我尝试了所有方法，但它不起作用
猜你喜欢
  • 1970-01-01
  • 2013-01-13
  • 2015-01-22
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
  • 1970-01-01
相关资源
最近更新 更多
热门标签
Java Python linux javascript Mysql C# Docker 算法 前端 SpringBoot Redis Vue spring 设计模式 .net core .net kubernetes c++ 数据库 数据结构 大数据 js 机器学习 微服务 Android Go 程序员 面试 JVM ASP.net core 云原生 人工智能 后端 PHP git CSS golang k8s Nginx Django mybatis 深度学习 多线程 React 架构 devops 爬虫 云计算 Spring Boot LeetCode