Reputation: 1727

ListView with CustomAdapter giving NullPointer Exception

I am using one listview to show details of places. For that i had created one CustomAdapter but i don't know why it is giving me Null Pointer Exception please help me to sort this problem.

This is my xml file.

activity_main.xml

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:scrollbars="vertical" />

</LinearLayout>

list_item.xml

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

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <ImageView
            android:id="@+id/img_hotel"
            android:layout_width="100dp"
            android:layout_height="match_parent" />

        <LinearLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical" >

            <TextView
                android:id="@+id/txt_hotelName"
                android:layout_width="fill_parent"
                android:layout_height="20dp" />

            <TextView
                android:id="@+id/txt_hotelAddress"
                android:layout_width="fill_parent"
                android:layout_height="20dp" />

            <RatingBar
                android:id="@+id/ratingBar"
                style="?android:attr/ratingBarStyleIndicator"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:numStars="5"
                android:rating="2.0"
                android:stepSize="0.5" />
        </LinearLayout>
    </LinearLayout>

</RelativeLayout>

This is my updated Custom Adapter

public class CustomListViewAdapter extends BaseAdapter {

Context context;

public CustomListViewAdapter(Context context, int resource,
        List<Result> results) {

    // super(context, resource, results);
    this.context = context;
    Log.v("Result Data in Adapter", results.toString());
    // TODO Auto-generated constructor stub
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    ViewHolder holder = null;
    Result result = (Result) getItem(position);
    LayoutInflater mInflater = (LayoutInflater) context
            .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);

    // LayoutInflater mInflater = (LayoutInflater)
    // context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
    if (convertView == null) {
        convertView = mInflater.inflate(R.layout.list_item, null);

        holder = new ViewHolder();
        holder.imgView = (ImageView) convertView
                .findViewById(R.id.img_hotel);
        holder.txtName = (TextView) convertView
                .findViewById(R.id.txt_hotelName);
        holder.txtAddress = (TextView) convertView
                .findViewById(R.id.txt_hotelAddress);
        holder.rate = (RatingBar) convertView
                .findViewById(R.id.ratingBar);
        convertView.setTag(holder);
    } else {
        /*
         * holder = (ViewHolder) convertView.getTag();
         * 
         * String url = result.icon; Log.e("URL is ", url); if (url !=
         * null) { Bitmap bitmap = fetchBitmapFromCache(url); if (bitmap
         * == null) { new
         * BitmapDownloaderTask(holder.imgView).execute(url); } else {
         * holder.imgView.setImageBitmap(bitmap); } } else {
         * holder.imgView.setImageBitmap(null); }
         */
        holder.imgView.setImageDrawable(getResources().getDrawable(
                R.drawable.ic_launcher));
        holder.txtName.setText(result.name);
        holder.txtAddress.setText(result.formatted_address);
        holder.rate.setRating(result.rating);
    }
    return convertView; // super.getView(position, convertView, parent);
}

private class ViewHolder {
    ImageView imgView;
    TextView txtName;
    TextView txtAddress;
    RatingBar rate;
}

@Override
public int getCount() {
    // TODO Auto-generated method stub
    return results.size();
}

@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return results.get(position);
}

@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return results.indexOf(getItem(position));
}

}

And here i have set the adapter to listView

list.setAdapter(new CustomListViewAdapter(MainActivity.this,
                R.layout.list_item, results));

This is my updated code upto now but it is still giving me null pointer exception.

and this is my stack strace.

03-13 11:13:20.355: E/AndroidRuntime(413): FATAL EXCEPTION: main
03-13 11:13:20.355: E/AndroidRuntime(413): java.lang.NullPointerException
03-13 11:13:20.355: E/AndroidRuntime(413):  at com.th.hotelreservationsystem.MainActivity$CustomListViewAdapter.getView(MainActivity.java:183)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.AbsListView.obtainView(AbsListView.java:1294)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.ListView.measureHeightOfChildren(ListView.java:1198)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.ListView.onMeasure(ListView.java:1109)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.View.measure(View.java:8171)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:696)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:306)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.View.measure(View.java:8171)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.View.measure(View.java:8171)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:526)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.View.measure(View.java:8171)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.View.measure(View.java:8171)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.ViewRoot.performTraversals(ViewRoot.java:801)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.os.Handler.dispatchMessage(Handler.java:99)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.os.Looper.loop(Looper.java:123)
03-13 11:13:20.355: E/AndroidRuntime(413):  at android.app.ActivityThread.main(ActivityThread.java:4627)
03-13 11:13:20.355: E/AndroidRuntime(413):  at java.lang.reflect.Method.invokeNative(Native Method)
03-13 11:13:20.355: E/AndroidRuntime(413):  at java.lang.reflect.Method.invoke(Method.java:521)
03-13 11:13:20.355: E/AndroidRuntime(413):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
03-13 11:13:20.355: E/AndroidRuntime(413):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
03-13 11:13:20.355: E/AndroidRuntime(413):  at dalvik.system.NativeStart.main(Native Method)

Please help me friends.

Upvotes: 1

Answers (6)

Mahaveer Muttha

Reputation: 1727

Thanks for help guys.

I got the solution and this is my updated code with comments.

3 Mistakes of my code. Thnks to guys who helped me

public class CustomListViewAdapter extends BaseAdapter {

    Context context;

    public CustomListViewAdapter(Context context, int resource,
            List<Result> results) {

         super(); // 1) here i was trying to call parameterised Constructor which          
                      // was wrong.
        this.context = context;

    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ViewHolder holder = null;
        Result result = (Result) getItem(position);
        LayoutInflater mInflater = (LayoutInflater) context
                .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);


        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.list_item, null);

            holder = new ViewHolder(); // 2) i had not instantiated View holder 
                                               //  here i did.
            holder.imgView = (ImageView) convertView
                    .findViewById(R.id.img_hotel);
            holder.txtName = (TextView) convertView
                    .findViewById(R.id.txt_hotelName);
            holder.txtAddress = (TextView) convertView
                    .findViewById(R.id.txt_hotelAddress);
            holder.rate = (RatingBar) convertView
                    .findViewById(R.id.ratingBar);
            convertView.setTag(holder);
        } else {

            holder = (ViewHolder) convertView.getTag();// 3) here by mistake i
   //had commited holde with other unwanted code. here removed it.
            holder.imgView.setImageDrawable(getResources().getDrawable(
                    R.drawable.ic_launcher));
            holder.txtName.setText(result.name);
            holder.txtAddress.setText(result.formatted_address);
            holder.rate.setRating(result.rating);
        }
        return convertView; // super.getView(position, convertView, parent);
    }

    private class ViewHolder {
        ImageView imgView;
        TextView txtName;
        TextView txtAddress;
        RatingBar rate;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return results.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return results.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return results.indexOf(getItem(position));
    }
}

Upvotes: 2

Kapil

Reputation: 46

You are setting your viewHolder to null in the starting of getView. You initialized it if convertView is null. But if convertView is not null, you used it directly. Don't forget viewHolder is null if convertView is not null.

 Add following code in the starting of else block:

holder = (ViewHolder) convertView.getTag();

Upvotes: 3

PrvN

Reputation: 2395

@Mahaveer Can you please make it

@Override
public int getCount() {
    return <Size of list items>;
}

hope this will fix your issue.

Upvotes: 1

Michał Z.

Reputation: 4119

You should return convertView in your getView method instead of calling:

return super.getView(position, convertView, parent); // replace this line by return convertView;

EDIT: So full answer would be something like this:

public class CustomListViewAdapter extends ArrayAdapter<Result>{

        Context context;

        public CustomListViewAdapter(Context context, int resource,
                List<Result> results) {

            super(context, resource, results);
            this.context = context; // 1
            Log.v("Result Data in Adapter", results.toString());
            // TODO Auto-generated constructor stub
        }

        private class ViewHolder {
            ImageView imgView;
            TextView txtName;
            TextView txtAddress;
            RatingBar rate; 
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            ViewHolder holder = null;
            Result result = getItem(position);
            LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            if (convertView == null ){
                convertView = mInflater.inflate(R.layout.list_item, null);
                holder = new ViewHolder(); //2
            //  holder.imgView = (ImageView)convertView.findViewById(R.id.img_hotel);
                holder.txtName = (TextView) convertView.findViewById(R.id.txt_hotelName);
                holder.txtAddress = (TextView) convertView.findViewById(R.id.txt_hotelAddress);
                holder.rate = (RatingBar)convertView.findViewById(R.id.ratingBar);
                convertView.setTag(holder);
            }else {
                holder = (ViewHolder) convertView.getTag();

                //holder.imgView.setImageResource();
                holder.txtName.setText(result.name);
                holder.txtAddress.setText(result.formatted_address);
                holder.rate.setRating(result.rating);
            }
            return convertView; //3
        }
    }

Upvotes: 1

tolgap

Reputation: 9778

You are setting your ViewHolder to null, but never initializing it.

So make your getView() like this:

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ViewHolder holder = null;
        Result result = getItem(position);
        LayoutInflater mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if (convertView == null ){
            holder = new viewHolder(); //initialize it
            convertView = mInflater.inflate(R.layout.list_item, null);
            ....
            convertView.setTag(holder);
        }...

Upvotes: 0

Pragnani

Reputation: 20155

Your context is null as you have not initialize it in the constructor,

try to initialize it like this

 public CustomListViewAdapter(Context context, int resource,
                List<Result> results) {
            super(context, resource, results);
           this.context=context;

        }

And also your viewholder is null

Try to initialize your view holder

 holder = new viewHolder();

Upvotes: 1

ListView with CustomAdapter giving NullPointer Exception

Answers (6)

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