java - 不能引用内部类中的非最终变量

Question

我试图在 ListView 的每一行中添加一个 CountDownTimer。我唯一可以为每行中的按钮使用 onClick 方法的地方是 CustomListAdapter 中。但我无法引用应该显示剩余时间的 TextView 。我收到此错误:

Cannot refer to a non-final variable holder inside an inner class defined in a different method

我尝试将支架设置为最终状态，但随后出现此错误:

The final local variable holder cannot be assigned. It must be blank and not using a compound assignment

这是我的代码:

    public class CustomTimerRowAdapter extends ArrayAdapter < TimerRow > {

      Context context;
      int height;

      public CustomTimerRowAdapter(Context context, int resourceId,
        List < TimerRow > items) {
        super(context, resourceId, items);
        this.context = context;
        // Height of screen from not Activity subclass
        height = context.getResources().getDisplayMetrics().heightPixels;
      }

      /* private view holder class */
      private class ViewHolder {
        TextView txtTimer;
        TextView txtName;
        Button bStartStop;
      }


      public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        final TimerRow rowItem = getItem(position);

        LayoutInflater mInflater = (LayoutInflater) context
          .getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        if (convertView == null) {
          convertView = mInflater.inflate(R.layout.timer_row, null);
          holder = new ViewHolder();
          // make layout params
          holder.txtTimer = (TextView) convertView.findViewById(R.id.tvTimes);
          holder.txtTimer.getLayoutParams().height = height / 10;
          holder.txtName = (TextView) convertView.findViewById(R.id.tvName);
          holder.txtName.getLayoutParams().height = height / 10;
          holder.bStartStop = (Button) convertView
            .findViewById(R.id.bStartStopTimer);
          holder.bStartStop.getLayoutParams().height = height / 10;

          convertView.setTag(holder);

        } else
          holder = (ViewHolder) convertView.getTag();

        holder.txtName.setText(rowItem.getName());

        holder.bStartStop.setOnClickListener(new OnClickListener() {
          final ViewHolder temp = new ViewHolder();@
          Override
          public void onClick(View v) {
            new CountDownTimer(30000, 1000) {

              public void onTick(long millisUntilFinished) {
                // THIS IS WHERE I CANNOT REFER TO THE NON-FINAL VARIABLE
                holder.txtTimer.setText("seconds remaining: " + millisUntilFinished / 1000);
              }

              public void onFinish() {
                holder.txtTimer.setText("done!");
              }
            }.start();

          }
        });
        return convertView;
      }
    }

关于如何解决这个问题有什么建议吗？

Answer 1

这应该有效:

最终 ViewHolder 持有者；

即最初不要将其分配为 null。