Question

这是我为我所在的大学写的第一个Android应用程序。它基本上是一个瘦客户端，它从站点上的xml读取数据并将其打印到List。我遇到了一个奇怪的问题但可以使用一些帮助。 EventsListActivity从文件中读取xml，将其放入HashMaps数组中，对其进行排序并将其放入SimpleAdapter中。我正在使用这个完全相同的代码用于我的DirectoryListActivity，它工作得很好。但是，EventsListActivity仅显示包含1行的空白列表。如果单击该行将显示正确的数据，并且xml文件中只有1行，因此这不是问题。但是，行中的TextView不显示任何内容。

我已经完成了代码，正在读取和存储xml。 SimpleAdapter的绑定似乎有问题。任何提示都会非常感激，如果你看到我在代码中可以做的更好的事情，请随时给我指点。以下是所需信息：

public class KCCEventsListActivity extends ListActivity {
    public static final ArrayList<HashMap<String, String>> eventsList = new ArrayList<HashMap<String, String>>();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.customlist);
        SimpleAdapter adapter = new SimpleAdapter(KCCEventsListActivity.this, eventsList, R.layout.customrow, new String[] {"summary", "date"}, new int[] {R.id.tvHeading, R.id.tvSubheading});

        if (eventsList.isEmpty()) {
            getEvents();
        }

        KCCEventsListActivity.this.setListAdapter(adapter);
    }

    @Override
    protected void onListItemClick(ListView lv, View v, int position, long id) {
        super.onListItemClick(lv, v, position, id);

        HashMap<String, String> event = eventsList.get(position);
        Toast.makeText(KCCEventsListActivity.this, event.get("date"), Toast.LENGTH_LONG).show();
        //Call AddtoCalendar Intent
    }

    protected void getEvents() {
        try {
            URL url = new URL(getString(R.string.KccEventsAddress));
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db = dbf.newDocumentBuilder();
            Document doc = db.parse(new InputSource(url.openStream()));
            doc.getDocumentElement().normalize();

            NodeList nodeList = doc.getElementsByTagName("EventItem");

            for (int i=0; i < nodeList.getLength(); i++) {
                Node node = nodeList.item(i);
                Element element = (Element)node;

                HashMap<String, String> entry = new HashMap<String, String>();

                NodeList titleList = element.getElementsByTagName("Summary");
                Element titleElement = (Element)titleList.item(0);
                titleList = titleElement.getChildNodes();
                entry.put("summary", titleList.item(0).getNodeValue());

                NodeList dateList = element.getElementsByTagName("StartTime");
                Element dateElement = (Element)dateList.item(0);
                dateList = dateElement.getChildNodes();
                entry.put("date", dateList.item(0).getNodeValue());

                NodeList orderList = element.getElementsByTagName("Seconds");
                Element orderElement = (Element)orderList.item(0);
                orderList = orderElement.getChildNodes();
                entry.put("order", orderList.item(0).getNodeValue());

                eventsList.add(entry);
            }

            Comparator<HashMap<String, String>> comparator = new Comparator<HashMap<String, String>>() {

                public int compare(HashMap<String, String> object1, HashMap<String, String> object2) 
                {       
                        return object1.get("order").compareToIgnoreCase(object2.get("order"));
                }
            };      
            Collections.sort(eventsList, comparator);

        } catch (Exception e) {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
        }
    }
}

CUSTOMLIST.XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<ListView android:id="@id/android:list"
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"></ListView>
  <TextView android:id="@id/android:empty" android:layout_width="match_parent" android:layout_height="match_parent" android:text="No data" />
</LinearLayout>

CUSTOMROW.XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView android:id="@+id/tvHeading" android:layout_width="wrap_content" android:layout_height="26dip" android:layout_alignParentTop="true" android:textSize="20sp" />
<TextView android:id="@+id/tvSubheading" android:layout_width="wrap_content" android:layout_height="22dip" android:layout_below="@id/tvHeading" android:textSize="16sp" />
</RelativeLayout>

Answer 1

也许尝试更换这些线？

SimpleAdapter adapter = new SimpleAdapter(KCCEventsListActivity.this, eventsList, R.layout.customrow, new String[] {"summary", "date"}, new int[] {R.id.tvHeading, R.id.tvSubheading});
KCCEventsListActivity.this.setListAdapter(adapter);

这些行：

SimpleAdapter adapter = new SimpleAdapter(this, eventsList, R.layout.customrow, new String[] {"summary", "date"}, new int[] {R.id.tvHeading, R.id.tvSubheading});
setListAdapter(adapter)

Answer 2

您是否尝试在创建适配器之前填充HashMap 或调用

adapter.notifyDataSetChanged()

更新后备数据时，需要ping适配器。

Answer 3

在多次查看代码后，我终于重写了Web服务以打印出不同风格的xml。这使代码完美运行。由于某种原因，以前使用的xml文件导致显示无法正常工作。我希望我有更多关于为什么会这样的信息。谢谢你的回答。

SimpleAdapter不在GUI上显示数据

3 个答案: