inflater.inflate gives nullpointer in Adapter getview method. Why?

Question

In my Android app I'm building my first custom adapter. I now run into a nullpointer at the line in which I inflate the convertView. See the code below:

private List<String> possibilitiesList = new ArrayList<String>();

public void setPossibilitiesList(List<String> possibilitiesList) {
    for (String possibility : possibilitiesList) {
        addItem(possibility);
    }
}

public void addItem (final String item) {
    possibilitiesList.add(item);
    notifyDataSetChanged();
}

private LayoutInflater inflater;

@Override
public View getView(final int position, View convertView, ViewGroup viewGroup) {
    Log.e(this, "is called here!!");
    ViewHolder holder = new ViewHolder();
    convertView = inflater.inflate(R.layout.list_item_posibility, viewGroup, false);
    holder.possibilityTitle = (TextView) convertView.findViewById(R.id.text_possibility);
    holder.possibilityTitle.setText(possibilitiesList.get(position));
    return convertView;
}

and in my fragment I set the possibilitiesList as follows:

List<String> list = Arrays.asList(getResources().getStringArray(R.array.the_possibilities));
Log.e(this, new Integer(list.size()).toString()); // outputs 8
adapter.setPossibilitiesList(list);

I am 100% sure that the list_item_posibility.xml exists (Android Studio also highlights is as being existing), so I'm kinda lost on why this gives a nullpointer.

Does anybody know what I could be doing wrong here?

Answer 1

private LayoutInflater inflater; is just declared not initialized

You need to pass the context to the constructor of adapter class and then use it to initialize inflater.

 new Yourcustomadapter(ActivityName.this); 
// pass the context here and other params

Then

 private LayoutInflater inflater; 
 public Yourcustomadapterr(Context context)
 {
      inflater = LayoutInflater.from(context);
 }

Also check this

http://developer.android.com/reference/android/view/View.html#getContext()

Answer 2

Your inflater is null, you need to set it to a reference of an inflater

private final LayoutInflater inflater;

public CustomAdapter(LayoutInflater inflater) {
  this.inflater = inflater;
}

@Override
public View getView(final int position, View convertView, ViewGroup viewGroup) {
    Log.e("this", "is called here!!");
    ViewHolder holder = new ViewHolder();
    convertView = inflater.inflate(R.layout.list_item_posibility, viewGroup, false);
    holder.possibilityTitle = (TextView) convertView.findViewById(R.id.text_possibility);
    holder.possibilityTitle.setText(possibilitiesList.get(position));
    return convertView;
}

Then where you new up your adapter, either: (depending on where you init the adapter)

new CustomAdapter(LayoutInflater.from(this));

or

new CustomAdapter(LayoutInflater.from(context));

or

new CustomAdapter(getActivity().getLayoutInflater());

or

new CustomAdapter((LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE));