Error in button click in listview in android

Question

I have a listview which contains two textviews, an image and a button I want to do some function on button click with the current listview item. But I i use his code my app close while starting my adapter is

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    View rowView = convertView;
    ContactStockView sv = null;
    if (rowView == null) {
        // Get a new instance of the row layout view
        LayoutInflater inflater = activity.getLayoutInflater();
        rowView = inflater.inflate(
                R.layout.row, null);

        // Hold the view objects in an object,
        // so they don't need to be re-fetched
        sv = new ContactStockView();
        sv.name = (TextView) rowView.findViewById(R.id.textrow1);
        sv.number = (TextView) rowView.findViewById(R.id.textrow2);
        //ImageButton buy=(ImageButton)convertView.findViewById(R.id.btn_call);
        // Cache the view objects in the tag,
        // so they can be re-accessed later
        rowView.setTag(sv);
        ImageButton btn=(ImageButton)convertView.findViewById(R.id.btn_call);
        btn.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //Toast.makeText( activity, "abc", Toast.LENGTH_SHORT).show();
            }
        });
    } else {
        sv = (ContactStockView) rowView.getTag();
    }

    // Transfer the stock data from the data object
    // to the view objects
    ContactStock currentStock = (ContactStock) stocks.get(position);
    sv.name.setText(currentStock.getName());
    sv.number.setText(currentStock.getNumber());
    // TODO Auto-generated method stub
    return rowView;
}
 protected static class ContactStockView {
        protected TextView name;
        protected TextView number;
    }
 public void filter(String charText) {
        charText = charText.toLowerCase(Locale.getDefault());
        stocks.clear();
        if (charText.length() == 0) {
            stocks.addAll(arraylist);
        } else {
            for (ContactStock cs : arraylist) {
                if (cs.getName().contains(charText)) {
                    stocks.add(cs);
                }
            }
        }
        notifyDataSetChanged();
    }
 private OnClickListener callClickListner=new OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

    }
};

call button code

@Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                String phoneCallUri = "tel:" + phonenumber;
                 Intent phoneCallIntent = new Intent(Intent.ACTION_CALL);
                 phoneCallIntent.setData(Uri.parse(phoneCallUri));
                 startActivity(phoneCallIntent);
                //Toast.makeText( activity, "abc", Toast.LENGTH_SHORT).show();
            }

my adapeter class is

public ContactAdapter(Activity activity, List<ContactStock> objects) {
    super(activity, R.layout.row, objects);
    this.activity = activity;
    this.stocks = objects;
}

Answer 1

Change this

ImageButton btn=(ImageButton)convertView.findViewById(R.id.btn_call);

to

ImageButton btn=(ImageButton)rootView.findViewById(R.id.btn_call);

coz you have

rowView = inflater.inflate(R.layout.row, null);

findViewById looks for a view in the current inflated layout. You use the view object to initialize view.

Edit:

context.startActivity(phoneCallIntent);

startActivity() is a method of activity class. You need to pass the context to the constructor of adapter class initialize it and then use it like above statement

To pass

new CustomAdapter(MainActivtiy.this,..other params);

Then

Context context; public CustomAdapter(Context contex,..params) { this.context =context; }

Answer 2

You should replace this

   ImageButton btn=(ImageButton)convertView.findViewById(R.id.btn_call);

With

   ImageButton btn=(ImageButton)rowView.findViewById(R.id.btn_call);

Becoz your convertView==null at this position

Answer 3

还可以使用rowView而不是convertView将ImageButton初始化为：

ImageButton btn=(ImageButton)rowView.findViewById(R.id.btn_call);

Answer 4

change this line.....

 ImageButton btn=(ImageButton)convertView.findViewById(R.id.btn_call);

to this line..

ImageButton btn=(ImageButton)rowView.findViewById(R.id.btn_call);

in getview..