android checkbox onCheckedChanged is not invoked

Question

I have defined onCheckedChanged for the checkbox in my listview. When i click on the check box to check / uncheck it this function is getting invoked. But when i setthe state of the check box from code like

check.setChecked(true);

the onCheckedChanged is not getting invoked.

Please help.

Adapter file :

 package com.idg.project.adapters;

import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.ImageView;
import android.widget.TextView;

import com.idg.project.R;
import com.idg.project.activities.ScanListActivity;
import com.idg.project.activities.SearchResultActivity;
import com.idg.project.adapters.WishListAdapter.ViewHolder;
import com.idg.project.entity.ScannedProduct;

public class ScanListAdapter extends BaseAdapter {
    private Context context;
    private List<ScannedProduct> productList;
    protected LayoutInflater mInflater;
    Button showOrHideButton;
    static public int count = 0;
    String barcodeForSelectedRow;
    String formatForSelectedRow;
    OnItemClickListener rowListener;
    Activity parentActivity;
    boolean isWishList;

    public ScanListAdapter(Context context, List<ScannedProduct> objects,
            Button button, Activity parentActivity) {

        super();
        this.productList = objects;
        this.context = context;
        this.mInflater = LayoutInflater.from(context);
        showOrHideButton = button;
        this.parentActivity = parentActivity;
        this.isWishList = isWishList;
    }

    public int getCount() {

        return productList.size();
    }

    public Object getItem(int arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    public long getItemId(int arg0) {
        // TODO Auto-generated method stub
        return 0;
    }
@Override
public void notifyDataSetChanged() {
    // TODO Auto-generated method stub
    super.notifyDataSetChanged();
}
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        final int pos = position;
        Log.i("checkboxflag at : ", pos+"is"+(productList.get(pos).getCheckboxflag()));


            Log.i("getview : fresh", "getview"+pos);
            convertView = mInflater.inflate(R.layout.product_list_row, null);

            holder = new ViewHolder();
            holder.text1 = (TextView) convertView.findViewById(R.id.productid);
            holder.text1.setOnClickListener(new OnClickListener() {

                public void onClick(View v) {
                    Intent intent = new Intent(parentActivity,
                            SearchResultActivity.class);
                    intent.putExtra("barcode", productList.get(pos)
                            .getBarcode());
                    intent.putExtra("format", productList.get(pos).getFormat());
                    intent.putExtra("IsScan", false);
                    Log.i("", "" + productList.get(pos).getBarcode());
                    parentActivity.startActivity(intent);
                    Log.i("", "" + pos);

                }
            });
            holder.text2 = (TextView) convertView.findViewById(R.id.price);
            // holder.text2.setOnClickListener(listener);
            holder.image = (ImageView) convertView
                    .findViewById(R.id.productimageid);
            convertView.setTag(holder);
            // holder.image.setOnClickListener(listener);




        holder.text1.setText(productList.get(position).getTitle());
        holder.text2.setText(productList.get(position).getPrice().toString());
        if (productList.get(position).getSmallImage() != null) {
            byte[] bb = (productList.get(position).getSmallImage());
            holder.image.setImageBitmap(BitmapFactory.decodeByteArray(bb, 0,
                    bb.length));
        } else {
            holder.image.setImageBitmap(null);
            holder.image.setBackgroundResource(R.drawable.highlight_disabled);
        }

        // holder.image.setImageBitmap(Utils.loadBitmap(productList.get(position).getSmallImage()));
        final CheckBox check = (CheckBox) convertView
                .findViewById(R.id.checkbox);
        check.setClickable(true); // to remove anything carried over from prev convert view
        if(productList.get(pos).getCheckboxflag()==1)
        {
            Log.i("CheckBox set checked",""+pos);
            check.setChecked(true);

        }
        else{
            Log.i("CheckBox set unchecked",""+pos);
            check.setChecked(false);
        }
        setWishListItemsInScanList(pos, convertView);
        check.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            public void onCheckedChanged(CompoundButton buttonView,
                    boolean isChecked) {
                Log.i("OnclickListener","Current Position"+pos);
                if (check.isChecked()
                        && productList.get(pos).getWishListFlag() == 0) {

                    if(check.isClickable()){
                        Log.i("CheckBox check",""+pos);
                    ScanListActivity.updateCheckBoxSelection(1, pos);
                    ScanListAdapter.count++;
                    }

                } else if (!check.isChecked()
                        && productList.get(pos).getWishListFlag() == 0){
                    if(check.isClickable()){
                        ScanListActivity.updateCheckBoxSelection(0, pos);
                        ScanListAdapter.count--;
                        Log.i("CheckBox UNcheck",""+pos);
                        }



                }
                if (ScanListAdapter.count == 0) {
                    // showOrHideButton.setClickable(false);
                    // showOrHideButton.setVisibility(View.GONE);
                    showOrHideButton.setEnabled(false);
                } else {
                    // showOrHideButton.setVisibility(View.VISIBLE);
                    showOrHideButton.setEnabled(true);
                }

            }

        });
        return convertView;
    }

    private void setWishListItemsInScanList(int pos, View convertView) {
        if (productList.get(pos).getWishListFlag() == 1) {
            Log.i("CheckBox set checked from wish list",""+pos);
            CheckBox check = (CheckBox) convertView.findViewById(R.id.checkbox);
            check.setClickable(false);
            check.setChecked(true); 
        }

    }

    static class ViewHolder {
        TextView text1;
        ImageView image;
        TextView text2;
    }

}

List activity file :

   package com.idg.project.activities;

import java.util.ArrayList;
import java.util.List;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import com.idg.project.R;
import com.idg.project.adapters.WishListAdapter;
import com.idg.project.adapters.ScanListAdapter;
import com.idg.project.entity.ScannedProduct;
import com.idg.project.services.ScannedProductDataAccessManager;

public class ScanListActivity extends BaseActivity {
    static Button scanlist;
    ScanListAdapter listAdapter;
    static List<ScannedProduct> productList;

    /* Notes for the Developer : 
     * For tracking the checked items  Checkboxflag 
     * is maintained. 
     * Point1 : Select all will just set this flag in the local list and then call notifyDatachange of the adapter
     * within adapter the check box is set or reset based on this flag for each row
     * 
     * Point 2: When individual rows are selected , there is an onclick of the check box is invoked
     * Here the Checkboxflag of the local list is set /unset . Also we need a way to knpw the select all button is 
     * to enabled or diabled. for that Count variable is updated here. 
     * Now Important point is these two actions shoulnt be taking place if the checkbox state change due to select all
     * So there is a special check of isclickable in the onclicklistener 
     * 
     * Point 3: In scan list the items in the wish list are to be marked. This again needs special logic. 
     * This is done in the adapter code by checking all the rows whose wishListFlag is 1 and making it non clickable
     * 
     * Important : Listview has the concept of ViewGroup and each view group is usually the rows fitting in the display screen
     * so when we scroll, the viewGropu changes. 
     * Convertview is get reused for view groups. So need to careful undesired values that will be carried to next viewgroup*/

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.scan_list);
        productList = new ArrayList<ScannedProduct>();
        productList = getProductList();
        for(int i=0;i<productList.size();i++){
            Log.i("checkboxflag at : ", i+"is"+(productList.get(i).getCheckboxflag()));
        }
        final ListView lv = (ListView) findViewById(R.id.list);
        scanlist = (Button) findViewById(R.id.addtowishlist);
        scanlist.setEnabled(false);
        listAdapter = new ScanListAdapter(this, productList, scanlist, this);
        lv.setAdapter(listAdapter);
    }

    private List<ScannedProduct> getProductList() {
        List<ScannedProduct> productList = new ArrayList<ScannedProduct>();
        ScannedProductDataAccessManager productDataBaseManager = new ScannedProductDataAccessManager(
                getApplicationContext());
        String[] colList = { "title", "smallImage", "price" };
        productList = productDataBaseManager.fetchAllProducts();
        return productList;
    }

    static boolean selectFlag = false;

    public void selectAll(View view) {
        ListView listView = (ListView) findViewById(R.id.list);
        view = findViewById(R.id.select_all);
        if (selectFlag == false) {
            for (int i = 0; i < listView.getAdapter().getCount(); i++) {
                productList.get(i).setCheckboxflag(1);
            }
            view.setBackgroundResource(R.drawable.login_remme_dwn_btn);
            selectFlag = true;
            TextView text=(TextView) findViewById(R.id.select);
            text.setText("Unselect All");
            scanlist.setEnabled(true);
        } else {
            for (int i = 0; i < listView.getAdapter().getCount(); i++) {
                productList.get(i).setCheckboxflag(0);
            }
            view.setBackgroundResource(R.drawable.login_remme_up_btn);
            selectFlag = false;
            TextView text=(TextView) findViewById(R.id.select);
            text.setText("Select All");
            scanlist.setEnabled(false);

        }
        ((BaseAdapter)listView.getAdapter()).notifyDataSetChanged(); // we are only setting the flags in the list
                                            // so need to notify adapter to reflect same on checkbox state
        //listView.refreshDrawableState();
    }

    public void addToWishList(View view) {
        ListView listView = (ListView) findViewById(R.id.list);
        for (int i = 0; i < listView.getAdapter().getCount(); i++) {

                ScannedProduct product = productList.get(i);
                if (product.getWishListFlag() == 0 && product.getCheckboxflag()==1) {
                    product.setWishListFlag(1);
                    new ScannedProductDataAccessManager(getApplicationContext())
                            .updateProduct(product, "title",
                                    new String[] { product.getTitle() });
                    product.setCheckboxflag(0);
                    //ScanListAdapter.count--;
                }
                Log.i("ScanList selected", product.getTitle());

            }


        Toast.makeText(getApplicationContext(),
                "Added selected items to Wish List", Toast.LENGTH_SHORT).show();
        scanlist.setEnabled(false);
        ((BaseAdapter)listView.getAdapter()).notifyDataSetChanged();

    }
    static public void updateCheckBoxSelection(int flag,int pos){   // when individual row check box is checked/ unchecked
                                                                // this fn is called from adapter to update the list
        productList.get(pos).setCheckboxflag(flag);
    }

}

Answer 1

I got the answer / bug in my code

1. i am not reusing convertview so its every time a new holder.

2. I am changing the flag of the checkbox and then assigning a statechange listener for the checkbox thus its not getting invoked

when i changed the order to assign checkchangelistener before actually changing the state , its working as expected. The listener is getting called.

thanks all of you

Answer 2

Since your checkbox is inside listview, so you need to call notifyDataSetChanged method on your list's adapter to refresh it's contents.

---

update

instead of ((BaseAdapter)listView.getAdapter()).notifyDataSetChanged();, try calling listAdapter.notifyDataSetChanged();