Question

我是Android新手，并在youtube上关注了slidenerd的教程。这是我的代码。出于某种原因，它崩溃而没有出错。它适用于Android的常规适配器，但自定义适配器不起作用。请帮忙。感谢。

public List<String> teamsList = new ArrayList<String>();
public List<String> teamCities = new ArrayList<String>();
public List<String> teamDates = new ArrayList<String>();
    mListView = (ListView) findViewById(R.id.teamsList);
    mListView.setAdapter(new TeamsAdapter(this, teamsList, teamCities, teamDates));

class SingleRow {

    String team;
    String city;
    String date;

    public SingleRow(String team, String city, String date) {

        this.team = team;
        this.city = city;
        this.date = date;
    }
}

class TeamsAdapter extends BaseAdapter {

    public ArrayList<SingleRow> list;

    Context c;

    public TeamsAdapter(Context c, List<String> teamsList, List<String> teamCities, List<String> teamDates) {

        this.c = c;

        list = new ArrayList<SingleRow>();

        String[] teams = teamsList.toArray(new String[teamsList.size()]);
        String[] cities = teamCities.toArray(new String[teamCities.size()]);
        String[] dates = teamDates.toArray(new String[teamDates.size()]);

        for (int i=0;i<teams.length;i++) {
            list.add(new SingleRow(teams[i], cities[i], dates[i]));
        }
    }

    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int position) {
        return list.get(position);
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

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

        LayoutInflater inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View row = inflater.inflate(R.layout.team_row, parent, false);
        TextView team = (TextView) row.findViewById(R.id.team);
        TextView city = (TextView) row.findViewById(R.id.city);
        TextView date = (TextView) row.findViewById(R.id.date);
        SingleRow temp = list.get(position);
        team.setText(temp.team);
        city.setText(temp.city);
        date.setText(temp.date);

        return row;
    }
}

Answer 1

可能是inflater。如果您正在使用Activity，请尝试在TeamsAdapter的构造函数中传递LayoutInflater而不是Context。

 public TeamsAdapter(LayoutInflater inflater, List<String> teamsList, List<String> teamCities, List<String> teamDates)
{
  this.mInflater = inflater;
...
}

在你的getView函数中：

View row = mInflater.inflate(R.layout.team_row, parent, false);

在您实例化TeamsAdapter的代码中，我假设它是一个Activity派生类，请执行以下操作：

teamsAdapter =  new TeamsAdapter(this.getLayoutInflater(), ...);

Answer 2

为什么要将单元格视图扩展到父视图组？

View row = inflater.inflate(R.layout.team_row, null, false);

尝试使用null，我不确定这是否是问题。

Answer 3

考虑到你问题的当前内容，继续我的猜测：

第一次适配器视图调用getView时（调用setAdapter时），convertview参数始终为null。所以，你不能从那个arg得到一个布局inflater。将其更改为使用LayoutInflater.from(Context context)方法，而不是使用parent.getContext（）作为上下文。像，

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    LayoutInflater inflater = LayoutInflater.from(parent.getContext)
    ...

继续前进，这里有一篇关于如何很好地做适配器的文章。 http://developer.android.com/training/improving-layouts/smooth-scrolling.html

HTHS

Android自定义ListView适配器不工作：崩溃没有错误消息

3 个答案: