Question

i am having custom arrayadapter for listview, which has 5 views inside including checkbox, here i want to implement the select all checkboxes of listview and deselect all checkboxes, i tried with getchildat() method in the oncreate(), onresume(), and onpostcreate also but does not made luck to me. i appreciate if you can tell me the solution.

@Override
      public void onPostCreate(Bundle savedInstanceState){
          super.onPostCreate(savedInstanceState);

      Button selectall=(Button) findViewById(R.id.allselect);

      selectall.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            int count = listview.getCount();

            System.out.println("the count is "+count);
            for (int i = 0; i < listview.getLastVisiblePosition() - listview.getFirstVisiblePosition(); i++)  {

                RelativeLayout itemLayout = (RelativeLayout)listview.getChildAt(i);
                CheckBox cb = (CheckBox)itemLayout.findViewById(R.id.chkbx);
                cb.setChecked(true);

            }

        }
    });
  }

Arrayadapter class

@SuppressWarnings("unchecked")
    public MultipleLeadSyncAdapter(Context context, String[] values,String[] values1,List<Model> qrcode ,String[] values3,String[] values4,String[] values5) {
        super(context, R.layout.multipleselectlist, values1);
        this.context = context;
        this.values = values;
        this.values1 = values1;
        this.list=qrcode;
        this.values3=values3;
        this.values4=values4;
        this.eventid=values5;
    }

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 


    ViewHolder holder =null;
    if (convertView == null) {


            convertView = inflater.inflate(R.layout.multipleselectlist, parent, false);

            holder = new ViewHolder();
            holder.textView1 = (TextView) convertView.findViewById(R.id.multileadfirst_name);

            holder.textView3 = (TextView) convertView
                    .findViewById(R.id.multileadcompany_name);

            holder.rate=(RatingBar) convertView.findViewById(R.id.multileadlistrating);

            holder.chkbox = (CheckBox) convertView.findViewById(R.id.chkbx);

            holder.chkbox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

                @Override
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    int getPosition = (Integer) buttonView.getTag();  
                    list.get(getPosition).setSelected(buttonView.isChecked()); 
                }
            });

            convertView.setTag(holder);
            convertView.setTag(R.id.chkbx,holder.chkbox);
            convertView.setTag(R.id.multileadfirst_name,holder.textView1);
            convertView.setTag(R.id.multileadcompany_name,holder.textView3);
            convertView.setTag(R.id.multileadlistrating,holder.rate);

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


     holder = (ViewHolder) convertView.getTag();


    holder.textView1.setText(values[position]);

    if(values3[position].equals(" ")||values3[position].equals("null")||values3[position].equals("")){

    }else{

        String[] temp=values3[position].split(" ");

    }

    holder.textView3.setText(values1[position]);

    holder.rate.setRating(Float.valueOf(values4[position]).floatValue());

    String s = values[position];
    String ss = values1[position];

    System.out.println(s + ss );


    holder.chkbox.setTag(position);

    //holder.textView3.setText(list.get(position).getName());
    holder.chkbox.setChecked(list.get(position).isSelected());
    String igurl=values[position];
    System.out.println("the imagurl is "+igurl);

    return convertView;



}

class ViewHolder {

    String qrcode,Boothid;
    TextView textView1, textView2, textView3,textView4,textView5;
    RatingBar rate;
    ImageView imageView;
    CheckBox chkbox;

    public String getQrcode() {
        return qrcode;
    }

    public void setQrcode(String qrcode) {
        this.qrcode = qrcode;
    }

    public String getBoothID() {
        return Boothid;
    }

    public void setBoothID(String Boothid) {
        this.Boothid = Boothid;
    }

}

}

Answer 1

A ListView is just a presentation of data. The data is given to the ListView by an Adapter. This being said, I can explain what you did wrong:

Inside your OnClickListener, you are (un)checking a View of the ListView itself. This means the data is not being changed and the ListView which represents this data, does not display the wanted behavior.

A simple solution would be adding a boolean to your Model-object which indicates the checked-state:

Model {
   boolean isChecked = false;

   public void setChecked(boolean checked){
        isChecked = checked;
   }

   public boolean isChecked(){
        return isChecked;
   }
}

Whenever you click the ‘selectall’-button, you will simple toggle this boolean and notify the Adapter that his data has changed with the method notifyDataSetChanged. This will on his turn update the ListView itself. In pseudocode:

 onClick(..) {
     foreach (model inside my adapter){
         model.setChecked(true);
     }
     listview.getAdapter().notifyDataSetChanged()
 }

Last but not least, in the getView()-method inside your Adapter you can see if a Model is checked or not and act accordingly.

getView(...){

   if (listOfModel.get(position).isChecked){
       // do stuff, probably check a CheckBox
   } else {
       // uncheck...
   }

Good luck!