Listview With Viewholder And Checkbox State Save

Simple shopping list app. ListView (TextView + CheckBox with custom adapter. Tried to implement viewHolder pattern and completely lost. Am i right? Check my code. And also how to s

Solution 1:

Here is the proper implementation of your code-

privatestaticclassViewHolder {
                CheckBox checkBox;
                TextView textView;
            }

            publicShopAdapter(Context mainContex, ArrayList<ShopItem> shopItems) {
                this.mainContex = mainContex;
                this.shopItems = shopItems;
            }

            @OverridepublicintgetCount() {
                return shopItems.size();
            }

            @Overridepublic Object getItem(int position) {
                return shopItems.get(position);
            }

            @OverridepubliclonggetItemId(int position) {
                return position;
            }

            @Overridepublic View getView(int position, View convertView, ViewGroup parent) {
                finalShopItemshopItem= shopItems.get(position);
                ViewHolder viewHolder;
            if (convertView == null) { 
                    viewHolder = newViewHolder();

                    LayoutInflaterlayoutInflater= LayoutInflater.from(mContext);
                    convertView = layoutInflater.inflate(R.layout.shoplist_item, null);

                    viewHolder.textView = (TextView) item.findViewById(R.id.itemTextView);
                    viewHolder.checkBox = (CheckBox) item.findViewById(R.id.doneCheckBox);

            convertView.setTag(viewHolder);

        }
             else 
           {                
          viewHolder = (ViewHolder) convertView.getTag();
           }
viewHolder.checkBox.setTag(shopItems.get(position));
                    viewHolder.checkBox.setOnCheckedChangeListener(newCompoundButton.OnCheckedChangeListener() {
                        @OverridepublicvoidonCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                            if (isChecked) {
                                shopItem.setDone(true);
                                viewHolder.textView.setTextColor(mainContex.getResources()
                                        .getColor(R.color.done_text_color));
                            } else {
                                shopItem.setDone(false);
                                viewHolder.textView.setTextColor(mainContex.getResources()
                                        .getColor(R.color.secondary_text));
                            }
                        }
                    });




                viewHolder.textView.setText(shopItem.getDescription());
               viewHolder.checkBox.setChecked(shopItem.isDone());
                   return convertView;
            }

Solution 2:

See this implementation : (And for your checkbox .Do you want to retain checkbox state even after restarting app or just in scrolling ? )

// our ViewHolder.// caches our TextViewstaticclassViewHolderItem {
 TextView textViewItem;
  }

getView()

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

ViewHolderItem viewHolder;

/*
 * The convertView argument is essentially a "ScrapView".
 * It will have a non-null value when ListView is asking you recycle the row layout. 
 * So, when convertView is not null, you should simply update its contents instead of inflating a new row layout.
 */if(convertView==null){

    // inflate the layout
    LayoutInflater inflater = ((Activity) mContext).getLayoutInflater();
    convertView = inflater.inflate(layoutResourceId, parent, false);

    // well set up the ViewHolder
    viewHolder = new ViewHolderItem();
    viewHolder.textViewItem = (TextView) convertView.findViewById(R.id.textViewItem);

    // store the holder with the view.
    convertView.setTag(viewHolder);

}else{
    // we've just avoided calling findViewById() on resource everytime// just use the viewHolder
    viewHolder = (ViewHolderItem) convertView.getTag();
}

// object item based on the position
ObjectItem objectItem = data[position];

// assign values if the object is not nullif(objectItem != null) {
    // get the TextView from the ViewHolder and then set the text (item   name) and tag (item ID) values
    viewHolder.textViewItem.setText(objectItem.itemName);
    viewHolder.textViewItem.setTag(objectItem.itemId);
}

return convertView;

}

Solution 3:

use SparseBooleanArray

Try below code

publicclassShopAdapterextendsBaseAdapter {
private Context mainContex;
private ArrayList<ShopItem> shopItems;
boolean[] checkBoxState = newboolean[shopItems.size()];
private SparseBooleanArray mSelectedItemsIds;

staticclassViewHolder {
CheckBox checkBox;
TextView textView;
}

publicShopAdapter(Context mainContex, ArrayList<ShopItem> shopItems) {
this.mainContex = mainContex;
this.shopItems = shopItems;
mSelectedItemsIds = newSparseBooleanArray();
}

@OverridepublicintgetCount() {
return shopItems.size();
}


 @Overridepublic Object getItem(int position) {
return shopItems.get(position);
}

@OverridepubliclonggetItemId(int position) {
  return position;
}

@Overridepublic View getView(int position, View convertView, ViewGroup parent) {
finalShopItemshopItem= shopItems.get(position);
Viewitem= convertView;
if (item == null) {

    item = LayoutInflater.from(mainContex).inflate(R.layout.shoplist_item, null);

    finalViewHolderviewHolder=newViewHolder();
    viewHolder.textView = (TextView) item.findViewById(R.id.itemTextView);
    viewHolder.checkBox = (CheckBox) item.findViewById(R.id.doneCheckBox);

   if(mSelectedItemsIds.get(position)){
         shopItem.setDone(true);
         viewHolder.textView.setTextColor(mainContex.getResources().getColor(R.color.done_text_color));
    } else{
        shopItem.setDone(false);      
          viewHolder.textView.setTextColor(mainContex.getResources().getColor(R.color.secondary_text));
    }

    viewHolder.textView.setText(shopItem.getDescription());
    viewHolder.checkBox.setChecked(shopItem.isDone());
    viewHolder.checkBox.setOnCheckedChangeListener(newCompoundButton.OnCheckedChangeListener() {
        @OverridepublicvoidonCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {
                mSelectedItemsIds.put(position, value);
                shopItem.setDone(true);
                viewHolder.textView.setTextColor(mainContex.getResources()
                        .getColor(R.color.done_text_color));
            } else {
                mSelectedItemsIds.delete(position);
                shopItem.setDone(false);
                viewHolder.textView.setTextColor(mainContex.getResources()
                        .getColor(R.color.secondary_text));
            }
        }
    });
    item.setTag(viewHolder);
    viewHolder.checkBox.setTag(shopItems.get(position));
} else {
    item = convertView;
    ((ViewHolder) item.getTag()).checkBox.setTag(shopItems.get(position));
}
ViewHolderholder= (ViewHolder) item.getTag();
holder.textView.setText(shopItems.get(position).getDescription());
holder.checkBox.setChecked(shopItems.get(position).isDone());
return item;
}

}