Question

似乎无法确定我的适配器的问题。我试图在checkedTextView下放置一个进度条，以便最大限度地减少元素的数量和相对布局的麻烦（将加载栏放在下面，单选按钮放在{{1}的右侧}）。

textView

protected void onCreate(Bundle savedInstanceState)
{
...
    connections = new ArrayList<WifiP2pClient>();//make an arraylist for the connections
    listView = (ListView)findViewById(R.id.connectionsListView);//initialize the list view
    adapter = new P2PClientArrayAdapter(this, android.R.layout.simple_List_item_single_choice, connections);//create an array adapter
    listView.setAdapter(adapter);//attach the adapter to the listView
    listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
...
}

目前，问题是适配器无响应。我使用异步任务更新public class P2PClientArrayAdapter extends ArrayAdapter<WifiP2pClient> { private CheckedTextView checkedTextView; private ProgressBar progressBar; int lastRadioButtonPressed; CheckedTextView lastPressedTextView; public P2PClientArrayAdapter(Context context, int resource, List<WifiP2pClient> clients) { super(context, resource, clients); lastRadioButtonPressed = -1; lastPressedTextView = null; } @Override public View getView(final int position, View convertView, ViewGroup parent) { View row = convertView; WifiP2pClient client = getItem(position); if(row == null) { LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); row = inflater.inflate(R.layout.row_layout, parent, false); checkedTextView = (CheckedTextView)row.findViewById(R.id.clientToString); progressBar = (ProgressBar)row.findViewById(R.id.clientProgressBar); row.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(position != lastRadioButtonPressed) { if(lastPressedTextView != null) { lastPressedTextView.setChecked(false); } lastRadioButtonPressed = position; lastPressedTextView = checkedTextView; checkedTextView.setChecked(true); P2PClientArrayAdapter.this.notifyDataSetChanged(); } } }); } checkedTextView.setText(client.toString()); progressBar.setProgress(client.getProgress()); return row; } }并经常调用WifiP2pClient，但UI中显示的数据永远不会更新。另外，当我按notifyDataSetChanged()时，没有任何反应（甚至不是正常的黑色抑制动画）。

如果我使用常规的listView对象，ArrayListAdapter<String>会正确更新，所以我知道其余的代码正常运行，这个arrayList有问题。

编辑：我根据这篇文章将arrayAdapter放在onClickListener()中： How to use RadioGroup in ListView custom adapter?

EDIT2：我通过确保getView()和checkedViewText对象在视图未为空时被正确更新，我得到适配器以正确响应对其所做的更改以及用户的更改使用progressBar对象和视图的ViewHolder和setTag()功能。我很快就会粘贴这段代码。我仍然没有适配器为getTag()返回正确的值。

Answer 1

在做了足够的实验并获得幸运的休息之后，这是我完成的代码（对于未来的googlers和比较的缘故）。

public class P2PClientArrayAdapter extends ArrayAdapter<WifiP2pClient>
{
    //The viewholder object isn't neccessary but it allows us to Tag.set()
    //with no indicies because we have it wrapped in one big object
    private class ViewHolder
    {
        CheckedTextView checkedTextView;
        ProgressBar progressBar;
    }

    int lastRadioButtonPressed;
    CheckedTextView lastPressedTextView;

    public P2PClientArrayAdapter(Context context, int resource, List<WifiP2pClient> clients)
    {
        super(context, resource, clients);
        lastRadioButtonPressed = -1;
        lastPressedTextView = null;
    }

    //I wasn't sure how to override ListView's getCheckedItemPosition()
    //So I made my own and then changed the calling code.
    public int getCheckedItemPosition()
    {
        return lastRadioButtonPressed;
    }
    //If you delete an element in your list, you have 
    //to reset the pointer or you'll have logic errors.
    public void resetCheckedItemPosition()
    {
        lastRadioButtonPressed = -1;
        lastPressedTextView = null;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent)
    {
        View row = convertView;
        WifiP2pClient client = getItem(position);

        final ViewHolder viewHolder;

        if(row == null)
        {
            LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.row_layout, parent, false);

            viewHolder = new ViewHolder();
            viewHolder.checkedTextView = (CheckedTextView)row.findViewById(R.id.clientToString);
            viewHolder.progressBar = (ProgressBar)row.findViewById(R.id.clientProgressBar);

            row.setTag(viewHolder);
        }
        else
        {
            viewHolder = (ViewHolder)row.getTag();
        }
        row.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                if(position != lastRadioButtonPressed)
                {
                    if(lastPressedTextView != null)
                    {
                        lastPressedTextView.setChecked(false);
                    }
                    lastRadioButtonPressed = position;
                    lastPressedTextView = viewHolder.checkedTextView;
                    viewHolder.checkedTextView.setChecked(true);
                }
            }
        });
        viewHolder.checkedTextView.setText(client.toString());
        viewHolder.progressBar.setProgress(client.getProgress());
        return row;
    }
}

完全没有响应的Android自定义适配器

1 个答案: