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Android Android Lists and Adapters (2015) Lists with RecyclerViews Binding Data in the ViewHolder

Conuir Williamson
Conuir Williamson
7,825 Points
Posted by Conuir Williamson
Conuir Williamson
7,825 Points

Binding widgets in ViewHolder with ButterKnife

Has anyone managed to do the 'challenge' Ben proposed of binding the controls with ButterKnife?

My code works fine with the standard public field and casting each view in the constructor, but when I change it to use @Bind, none of the items get initialised.

Even if you haven't tried it, would you have any idea why this would be happening?

Kevin Faust
Kevin Faust
15,353 Points
Kevin Faust
Kevin Faust
15,353 Points

Do you get red squiggly lines when using @Bind?

Conuir Williamson
Conuir Williamson
7,825 Points
Conuir Williamson
Conuir Williamson
7,825 Points

Nope. Everything was just as it was everywhere else I used it. Had all imports too. I wouldn't have been able to tell they weren't initialised if I had red squigglies as I wouldn't have been able to even run it. :/

Sergey Valevich
Sergey Valevich
6,041 Points
Sergey Valevich
Sergey Valevich
6,041 Points

The same problem: I get the NullPointerExceptions on the views in ViewHolder.

    public class HourViewHolder extends RecyclerView.ViewHolder {
        @Bind(R.id.timeLabel) TextView mTimeLabel;
        @Bind(R.id.temperatureLabel)TextView mTemperatureLabel;
        @Bind(R.id.summaryLabel)TextView mSummaryLabel;
        @Bind(R.id.iconImageView)ImageView mIconImageView;

        public HourViewHolder(View itemView) {
            super(itemView);
            ButterKnife.bind(itemView);

        }

        public void bindHour (Hour hour) {
            mTemperatureLabel.setText(hour.getTemperature() + "");
            mSummaryLabel.setText(hour.getSummary());
            mIconImageView.setImageResource(hour.getIconId());
            mTimeLabel.setText(hour.getHourOfTheDay());
        }
    }

1 Answer

Philip G
Philip G
14,600 Points
Philip G
Philip G
14,600 Points

Hi there,

According to this site you have to call the ButterKnife.bind method with different parameters in ListViews. I also had that error and this code works fine for me:

HourViewHolder.java 
public class HourViewHolder extends RecyclerView.ViewHolder {

        @Bind(R.id.timeLabel) TextView mTimeLabel;
        @Bind(R.id.summaryLabel) TextView mSummaryLabel;
        @Bind(R.id.temperatureLabel) TextView mTemperatureLabel;
        @Bind(R.id.iconImageView) ImageView mIconImageView;

        public HourViewHolder(View itemView) {
            super(itemView);

            ButterKnife.bind(this, itemView);

        }

        public void bindHour(Hour hour) {
            mTimeLabel.setText(hour.getHour());
            mSummaryLabel.setText(hour.getSummary());
            mTemperatureLabel.setText(hour.getTemperature()+"");
            mIconImageView.setImageResource(hour.getIconId());
        }
    }

Best regards,

Philip