Question

我有一个项目列表，在点击项目之后，应该设置ProgressBar我想要设置的进度值。我已经这样做了，但它不起作用（它没有显示设置的进度值）。

HashMap<Integer,Boolean> states = new HashMap<Integer, Boolean>();
@Override
public View getView(final int position, View convertView, ViewGroup parent) {

    View view = convertView;
    if (view == null) {
        view = lInflater.inflate(R.layout.my_list_item, parent, false);
    }


    progressBar = ((ProgressBar) view.findViewById(R.id.progress_bar));

    playButton  = ((ImageButton) view.findViewById(R.id.play_pause));

    playButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View view) {

            if(states.containsKey(position))
            {
                states.put(position, !states.get(position));
                playButton = ((ImageButton) view.findViewById(R.id.play_pause));
                playButton.setImageResource(states.get(position) ? R.drawable.button_pause : R.drawable.button_play);

                // Here i set the tag that the row of listview is clicked
                progressBar.setTag(position);

            }
            else
            {
                states.put(position, true);
                playButton = ((ImageButton) view.findViewById(R.id.play_pause));
                playButton.setImageResource(R.drawable.button_pause);

                // Here i set the tag that the row of listview is clicked
                progressBar.setTag(position);
            }



            // Here i want to get the clicked progressBar using the tag we set above
            progressBar.setProgress(100); // Does not work.... no effect on progressBar


            }
        }
    return view;
}

我试过这些，但没有锁定。我认为，问题是，如果我使用视图，我得到空指针异常。也许是因为，我试图访问playButton的onClick（View视图）中的视图。我不知道如何解决它，任何帮助都将不胜感激。

progressBar = ((ProgressBar) view.getTag());
progressBar = ((ProgressBar) convertView.getTag());

Answer 1

你的方法的问题是OnClickListener是一个回调函数，它不是作为getView方法的一部分执行的，而是在一个封闭类的属性中保存对ProgressBar的引用，实际上每个属性都被覆盖列表中的行，实际上只保留引用的最后一个ProgressBar。因此，每次单击任何行时，实际上都会更新最后渲染的ProgressBar。

解决方案是将最后一个变量中的进度条引用作为封闭的getView方法上下文的一部分。

HashMap<Integer,Boolean> states = new HashMap<Integer, Boolean>();
@Override
public View getView(final int position, View convertView, ViewGroup parent) {

    View view = convertView;
    if (view == null) {
        view = lInflater.inflate(R.layout.my_list_item, parent, false);
    }


    final ProgressBar progressBar = ((ProgressBar) view.findViewById(R.id.progress_bar));

    final ImageButton playButton  = ((ImageButton) view.findViewById(R.id.play_pause));

    playButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View view) {

            if(states.containsKey(position))
            {
                states.put(position, !states.get(position));
                playButton.setImageResource(states.get(position) ? R.drawable.button_pause : R.drawable.button_play);

                // Here i set the tag that the row of listview is clicked
                progressBar.setTag(position);

            }
            else
            {
                states.put(position, true);
                playButton.setImageResource(R.drawable.button_pause);

                // Here i set the tag that the row of listview is clicked
                progressBar.setTag(position);
            }



            // Here i want to get the clicked progressBar using the tag we set above
            progressBar.setProgress(100); // Does not work.... no effect on progressBar


            }
        }
    return view;
}

Android列表视图，多个进度条无法正常工作

1 个答案: