如何在Android中的GridView滚动上保留复选框状态 [英] How to retain the checkbox state on scroll of gridview in android

问题描述

• 我在做什么 ::我有一个gridview用来显示图像，gridview的适配器具有图像和checkbox
• 正在发生的事情 ::当我选中复选框并向下滚动gridview时，当我scrollback时，所选的checkbox为 未选择
• 问题 ::如何防止这种情况，我需要在代码中进行哪些更改

• What i am doing:: I have a gridview where i am displaying images I adapter of the gridview has image and a checkbox
• What is happening:: When i check the checkbox and i scroll the gridview down & when i scrollback, the selected checkbox is unselected
• Question:: How can i prevent this What changes should i need to make in the code

grid_view_image_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <ImageView
        android:id="@+id/flag"
        android:layout_width="150dp"
        android:layout_height="150dp"
        android:layout_alignParentRight="true"
        android:scaleType="centerCrop"
        android:background="#000000"
        android:padding="1dp" />

    <CheckBox
        android:id="@+id/ch_bx"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="CheckBox" />

</RelativeLayout>

AdapterGridViewImage.java

public class AdapterGridViewImage extends BaseAdapter {

    // Declare Variables
    Context context;
    LayoutInflater inflater;
    ArrayList<HashMap<String, String>> data;
    HashMap<String, String> resultp = new HashMap<String, String>();

    public AdapterGridViewImage(Context context,
            ArrayList<HashMap<String, String>> arraylist) {
        this.context = context;
        data = arraylist;
        //imageLoader = new ImageLoader(context);
    }

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

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {
        ImageView flag;
        CheckBox ch_bx;
        inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View itemView = inflater.inflate(R.layout.grid_view_image_item, parent, false);
        resultp = data.get(position);
        flag = (ImageView) itemView.findViewById(R.id.flag);
        ch_bx=(CheckBox) itemView.findViewById(R.id.ch_bx);
        //Picasso.with(context).load("http://10.0.2.2:3009/buffet_items/".trim()+resultp.get("item_image").trim()).into(flag);

         Picasso.with(context)
          .load("http://10.0.2.2:3009/buffet_items/".trim()+resultp.get("item_image").trim())
          .resizeDimen(R.dimen.wanted_size,R.dimen.wanted_size).centerCrop().into(flag);

        return itemView;
    }
}

推荐答案

请修改您的代码.
1)我们必须使用ViewHolder类进行封装.
2)我们必须设置复选框的标签值，以便在那时重新创建视图时，我们可以从标签中获取值.

Please modify your code.
1) We have to use ViewHolder class for encapsulation.
2) We have to set tag values of checkbox so when view recreate at that time we can take values from tag.

 public AdapterGridViewImage(Context context,
                        ArrayList<HashMap<String, String>> arraylist) {
                    this.context = context;
                    data = arraylist;
                    //imageLoader = new ImageLoader(context);
                    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

            }

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

            @Override
            public Object getItem(int position) {
                return null;
            }

            @Override
            public long getItemId(int position) {
                return 0;
            }

            public View getView(final int position, View convertView, ViewGroup parent) 
            {
                final ViewHolder holder;
                if(convertView==null)
                {
                    holder=new ViewHolder();
                    convertView = inflater.inflate(R.layout.grid_view_image_item, parent, false);
                    holder.flag = (ImageView) convertView.findViewById(R.id.flag);
                    holder.ch_bx=(CheckBox) convertView.findViewById(R.id.ch_bx);
holder.ch_bx.setTag(false);
                    convertView.setTag(holder);
                }
                else
                {
                    holder=(ViewHolder)convertView.getTag();
                }

                resultp = data.get(position);

                if((Boolean)holder.ch_bx.getTag())
                {
                    holder.ch_bx.setChecked(true);
                }
                else
                {
                    holder.ch_bx.setChecked(false);
                }

                holder.ch_bx.setOnClickListener(new OnClickListener()
                {

                    @Override
                    public void onClick(View v)
                    {
                        if(holder.ch_bx.isChecked())
                        {
                            holder.ch_bx.setTag(true);
                        }
                        else
                        {
                            holder.ch_bx.setTag(false);
                        }
                    }
                });
                //Picasso.with(context).load("http://10.0.2.2:3009/buffet_items/".trim()+resultp.get("item_image").trim()).into(flag);

                 Picasso.with(context)
                  .load("http://10.0.2.2:3009/buffet_items/".trim()+resultp.get("item_image").trim())
                  .resizeDimen(R.dimen.wanted_size,R.dimen.wanted_size).centerCrop().into(holder.flag);

                return itemView;
            }
            class ViewHolder
            {
                ImageView flag;
                CheckBox ch_bx;
            }

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