ObjectPool的Stack或LinkedList？(Stack or LinkedList for ObjectPool?)

 最后我最终创建了自己的自定义适配器，这样我至少可以更容易地理解发生了什么。 
 
 我必须创建几个多选列表，其中一些填充数据库中的数据，另一些填充来自共享首选项。 
 
 对于这个显示来自数据库的数据，我创建了以下适配器（我注释了关于图标的行，因为我还没有设置它们）： 
 
public class CategoriesLVAdapter extends BaseAdapter {
private Context mContext;
private LayoutInflater mInflater;
private List<Category> categoriesList;

// Constructor
public CategoriesLVAdapter(Context c, List<Category> categories_list){
    mContext = c;
    mInflater = LayoutInflater.from(c);
    categoriesList = categories_list;
}

public List<Category> getCategoriesList(){
    return categoriesList;
}

@Override
public int getCount() {
    return categoriesList.size();
}

@Override
public Object getItem(int position) {
    return categoriesList.get(position);
}

@Override
public long getItemId(int position) {
    return categoriesList.get(position).getID();
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder = null;
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.categories_list_row, null);
        //convertView.setLayoutParams(new ListView.LayoutParams(200, 90));
        holder = new ViewHolder();
        holder.title = (TextView) convertView.findViewById(R.id.categories_list_row_tv);
        //holder.icon = (ImageView) convertView.findViewById(R.id.categories_list_row_iv);

        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();         
    }

    //holder.icon.setImageResource(categoriesList.get(position).getDrawableID());
    //holder.icon.setAdjustViewBounds(true);  
    //holder.icon.setScaleType(ImageView.ScaleType.CENTER_CROP);        
    holder.title.setText(categoriesList.get(position).getName());

    return convertView;
}

static class ViewHolder {
    TextView title;
    //ImageView icon;
}
 
 } 
 
 在我的活动中，我在调用AlertDialog来填充ListView时使用此适配器，然后使用共享首选项中保存的最后一个预先选择类别： 
 
private void categoriesFilter(){
    AlertDialog.Builder alt_bld = new AlertDialog.Builder(this);
    alt_bld.setTitle(resources.getText(R.string.select_categories).toString());

    LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);   
    View layout = inflater.inflate(R.layout.categories_list,(ViewGroup) findViewById(R.id.categories_layout_root));
    categoriesLV = (ListView) layout.findViewById(R.id.categories_list);

    alt_bld.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            String selectedCategoriesString = getSelectedValues(categoriesLV);

            //Update the shared preferences
            prefs.edit().putString(RateDayApplication.PREF_KEY_CATEGORIES, selectedCategoriesString).commit();

            updateFilterDisplay(resources.getText(R.string.cat_title).toString(), selectedCategoriesString, searchedCategoriesTV, "Category");
        }
    });

    alt_bld.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            dialog.cancel();
        }
    });

    String selectedCategoriesString = prefs.getString(RateDayApplication.PREF_KEY_CATEGORIES, new String());
    categoriesLV.setAdapter(new CategoriesLVAdapter(this, categoriesList));

    String[] selectedCategoriesArray = selectedCategoriesString.split(",");

    int categoriesLVLength = categoriesLV.getCount();
    for(int i = 0; i < categoriesLVLength; i++){
        int categoryID = ((Category) categoriesLV.getItemAtPosition(i)).getID();
        if(Arrays.asList(selectedCategoriesArray).contains(String.valueOf(categoryID))){
            categoriesLV.setItemChecked(i, true);
        }
    }

    alt_bld.setView(layout);

    AlertDialog alert = alt_bld.create();   
    alert.show();
}
 
 最后，这是我从数据库处理程序调用的函数，以获取catagories列表： 
 
// Getting All Categories By ID desc
    public List<Category> getCategoriesList() {
        String selectQuery = "SELECT " + CATEGORY_ID + ", " + CATEGORY_NAME + " FROM " + CATEGORY_TABLE + " ORDER BY " + CATEGORY_ID + " ASC";
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null); 

        List<Category> categoriesList = new ArrayList<Category>();//String[] categoriesList = {};

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                Category category = new Category(cursor.getInt(0), cursor.getString(1), false);
                categoriesList.add(category);
            } while (cursor.moveToNext());
        }

        cursor.close();
        db.close();
        return categoriesList;
    }
 
 我认为我之前遇到的问题是因为函数“setItemChecked”有点误导，因为它并不一定意味着必须检查任何东西。 当您使用“setItemChecked”函数时，列表视图中的项目将被选中，有或没有复选框（我的行只包含文本视图）。 
 
 在我的列表中选择的行显示为不同的颜色，这在我看来足够简单的多选列表。 
 
 我使用的布局非常简单，“categories_list”包含LinearLayout中的ListView，“categories_list_row”包含LinearLayout中的TextView。 
 
 希望它可以指导某人！ 

Finally I ended up creating my own custom adapter, this way I could at least understand more easily what was happening.
 
I had to create actually several multiselect lists, some populated with data from the database, others from the shared preferences.
 
For this one displaying data from the DB, I created the following adapter (I commented out the lines about the icons because I did not set them up yet):
 
public class CategoriesLVAdapter extends BaseAdapter {
private Context mContext;
private LayoutInflater mInflater;
private List<Category> categoriesList;

// Constructor
public CategoriesLVAdapter(Context c, List<Category> categories_list){
    mContext = c;
    mInflater = LayoutInflater.from(c);
    categoriesList = categories_list;
}

public List<Category> getCategoriesList(){
    return categoriesList;
}

@Override
public int getCount() {
    return categoriesList.size();
}

@Override
public Object getItem(int position) {
    return categoriesList.get(position);
}

@Override
public long getItemId(int position) {
    return categoriesList.get(position).getID();
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder = null;
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.categories_list_row, null);
        //convertView.setLayoutParams(new ListView.LayoutParams(200, 90));
        holder = new ViewHolder();
        holder.title = (TextView) convertView.findViewById(R.id.categories_list_row_tv);
        //holder.icon = (ImageView) convertView.findViewById(R.id.categories_list_row_iv);

        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();         
    }

    //holder.icon.setImageResource(categoriesList.get(position).getDrawableID());
    //holder.icon.setAdjustViewBounds(true);  
    //holder.icon.setScaleType(ImageView.ScaleType.CENTER_CROP);        
    holder.title.setText(categoriesList.get(position).getName());

    return convertView;
}

static class ViewHolder {
    TextView title;
    //ImageView icon;
}
 
}
 
In my activity, I use this adapter when the AlertDialog is called to populate the ListView, then I pre-select the categories using the last ones saved in the shared preferences:
 
private void categoriesFilter(){
    AlertDialog.Builder alt_bld = new AlertDialog.Builder(this);
    alt_bld.setTitle(resources.getText(R.string.select_categories).toString());

    LayoutInflater inflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);   
    View layout = inflater.inflate(R.layout.categories_list,(ViewGroup) findViewById(R.id.categories_layout_root));
    categoriesLV = (ListView) layout.findViewById(R.id.categories_list);

    alt_bld.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            String selectedCategoriesString = getSelectedValues(categoriesLV);

            //Update the shared preferences
            prefs.edit().putString(RateDayApplication.PREF_KEY_CATEGORIES, selectedCategoriesString).commit();

            updateFilterDisplay(resources.getText(R.string.cat_title).toString(), selectedCategoriesString, searchedCategoriesTV, "Category");
        }
    });

    alt_bld.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        public void onClick(DialogInterface dialog, int whichButton) {
            dialog.cancel();
        }
    });

    String selectedCategoriesString = prefs.getString(RateDayApplication.PREF_KEY_CATEGORIES, new String());
    categoriesLV.setAdapter(new CategoriesLVAdapter(this, categoriesList));

    String[] selectedCategoriesArray = selectedCategoriesString.split(",");

    int categoriesLVLength = categoriesLV.getCount();
    for(int i = 0; i < categoriesLVLength; i++){
        int categoryID = ((Category) categoriesLV.getItemAtPosition(i)).getID();
        if(Arrays.asList(selectedCategoriesArray).contains(String.valueOf(categoryID))){
            categoriesLV.setItemChecked(i, true);
        }
    }

    alt_bld.setView(layout);

    AlertDialog alert = alt_bld.create();   
    alert.show();
}
 
Finally here is the function I call from my database handler to get the list of catagories:
 
// Getting All Categories By ID desc
    public List<Category> getCategoriesList() {
        String selectQuery = "SELECT " + CATEGORY_ID + ", " + CATEGORY_NAME + " FROM " + CATEGORY_TABLE + " ORDER BY " + CATEGORY_ID + " ASC";
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null); 

        List<Category> categoriesList = new ArrayList<Category>();//String[] categoriesList = {};

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                Category category = new Category(cursor.getInt(0), cursor.getString(1), false);
                categoriesList.add(category);
            } while (cursor.moveToNext());
        }

        cursor.close();
        db.close();
        return categoriesList;
    }
 
I think my problem before was coming from the fact that the function "setItemChecked" is a little misleading because it does not mean necessarily that anything is checked. When you use the function "setItemChecked", the item in the list view becomes selected, with or without a checkbox (my rows only contain text views).
 
The rows selected in my list appear in a different color, and that's enough in my opinion for a simple multi selection list.
 
The layouts I used are quite simple, "categories_list" contains a ListView in a LinearLayout and "categories_list_row" contains a TextView in a LinearLayout.
 
Hope it may guide someone!