android ListView 优雅高效的adapter

public class SetAdapter extends ArrayAdapter {

    private List<SetData> _content;
    private final int _resourceId;
    private int _positionOnTouch = -1;
    private OnChangedTextListener _editChangeListener;

    interface OnChangedTextListener {
        void onChangedTextListener(int position, String str);
    }

    class ViewHolder implements TextWatcher {
        int position;
        TextView tvName;
        TextView tvRange;
        TextView tvValue;
        EditText edtText;
        boolean notifyEnable = false;

        ViewHolder(View view, int position, int... id) {
            this.position = position;
            this.tvName = (TextView) view.findViewById(id[0]);
            this.tvRange = (TextView) view.findViewById(id[1]);
            this.tvValue = (TextView) view.findViewById(id[2]);
            this.edtText = (EditText) view.findViewById(id[3]);
        }

        public void updatePosition(int position) {
            this.position = position;
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
        }

        @Override
        public void afterTextChanged(Editable s) {
            if (notifyEnable && _editChangeListener != null) {
                _editChangeListener.onChangedTextListener(this.position, s.toString());
            }
        }
    }

    public SetAdapter(Context context, int textViewResourceId, List<SetData> objects) {
        super(context, textViewResourceId, objects);
        _resourceId = textViewResourceId;
        _content = objects;
        _editChangeListener = new OnChangedTextListener() {
            @Override
            public void onChangedTextListener(int position, String str) {
                SetData item = _content.get(position);
                item.setFiled(3, str);
            }
        };
    }

    public List<SetData> getContent() {
        return _content;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup viewGroup) {

    //String info = String.format("into getView, pos=%d", position);
    //Log.e("gmx", info);

        ViewHolder vh;
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(_resourceId, null);
            vh = new ViewHolder(convertView, position, R.id.list_name, R.id.list_range, R.id.list_value, R.id.list_value_set);
            convertView.setTag(vh);
        } else {
            vh = (ViewHolder) convertView.getTag();
            vh.updatePosition(position);
        }

        SetData item = (SetData) getItem(position);

        vh.notifyEnable = false;

        vh.edtText.setTag(vh);

        vh.edtText.setText(item.getField(3));

        vh.tvName.setText(item.getField(0));
        //   vh.tvName.setTextColor(item.textColor[0]);
        //   vh.tvName.setBackgroundColor(item.bkColor[0]);

        vh.tvRange.setText(item.getField(1));
        //   vh.tvRange.setTextColor(item.textColor[1]);
        //   vh.tvRange.setBackgroundColor(item.bkColor[1]);
        vh.tvValue.setText(item.getField(2));
        //   vh.tvValue.setTextColor(item.textColor[2]);
        //   vh.tvValue.setBackgroundColor(item.bkColor[2]);

        vh.edtText.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                ((ViewGroup) v.getParent()).setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
                ViewHolder viewHolder = (ViewHolder) v.getTag();
                _positionOnTouch = viewHolder.position;
                ((EditText) v).addTextChangedListener(viewHolder);
                return false;
            }
        });
        convertView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                ((ViewGroup) v).setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
                return false;
            }
        });
        vh.notifyEnable = true;
        if (_positionOnTouch == position) {
            vh.edtText.requestFocus();
            vh.edtText.setSelection(vh.edtText.getText().length());
        } else {
            vh.edtText.clearFocus();
        }
        return convertView;
    }
}