Timer в ListView

MyAdapter.java

package com.ivanovsuper.timerprogress;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageButton;
import android.widget.ProgressBar;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;

public class MyAdapter extends ArrayAdapter<String> {

    private final Timer timer;
    private ArrayList<TimerTask> mTimers;
    private final Context context;
    private final String[] values;

    public MyAdapter(Context context, String[] values) {
        super(context, R.layout.list_item, values);
        this.context = context;
        this.values = values;
        mTimers = new ArrayList<>(values.length);
        timer = new Timer("MyAdapterTimer");
    }

    //Вызвать при onPause фрагмента/активити
    public void cancelTimers(){
        for(TimerTask task: mTimers){
            task.cancel();
        }
        timer.cancel();
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent)
    {
        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View rowView = inflater.inflate(R.layout.list_item, parent, false);
        final ProgressBar progress = (ProgressBar) rowView.findViewById(R.id.progress_bar);
        TextView time = (TextView) rowView.findViewById(R.id.time_text);
        final TextView percentage = (TextView) rowView.findViewById(R.id.percentage_text);
        percentage.setText(values[position]);
        ImageButton button1 = (ImageButton) rowView.findViewById(R.id.button_1);
        ImageButton button2 = (ImageButton) rowView.findViewById(R.id.button_2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //todo отменить предыдущее выполнение или блокировать кнопку
                timer.scheduleAtFixedRate(mTimers.get(position),0,1000);//раз в секунду
            }
        });
        mTimers.add(new TimerTask() {
            @Override
            public void run() {
                progress.post(new Runnable() {
                    @Override
                    public void run() {
                        //todo проверить на 100% остановить таймер mTimers.get(position).cancel()
                        progress.setProgress(progress.getProgress()+1);
                    }
                });
            }
        });
        return rowView;
    }
}