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我有一个从数据库中获取的位置的列表视图，我在项目上创建了一个 OnItemLongClickListener，在长按后，在消息正文中激活了带有一些信息的警报对话框，这些信息是我从数据库中获取的有关项目的信息点击。该对话框有 3 个工作正常的按钮（呼叫、映射它和查看照片）。该对话框适用于前 8 个项目，然后对话框不打开，应用程序强制关闭其余项目，我不知道为什么！

你能帮我么？

这是显示所有酒店列表的代码：

List<Hotel> values = datasource.getAllHotels();
            if (values.isEmpty())
            {
                Toast.makeText(this, "No results found!", Toast.LENGTH_LONG).show();
                Intent i1 = new Intent(hotelSearchList.this, hotelSearch.class);
                startActivity(i1);
            }
            ArrayAdapter<Hotel> adapter = new ArrayAdapter<Hotel>(this,
                    android.R.layout.simple_list_item_1, values);
            setListAdapter(adapter);
            ListView lv = getListView();
            lv.setOnItemLongClickListener(this);

这是 onItemLongClickListener 的代码：

public boolean onItemLongClick(final AdapterView<?> parent, final View view, int position,
        long id) {
    // TODO Auto-generated method stub
    String hotelName = (String) ((TextView)parent.getChildAt(position)).getText();
    final List<Hotel> location = datasource.getHotelLocation(hotelName);
    String loc = "Location: " + TextUtils.join(", ", location);
    List<Hotel> address = datasource.getHotelAddress(hotelName);
    String add = "Address: " + TextUtils.join(", ", address);
    List<Hotel> rating = datasource.getHotelRating(hotelName);
    String rat = "Rating: " + TextUtils.join(", ", rating);
    List<Hotel> phone = datasource.getHotelPhone(hotelName);
    final String phoneN = "Phone: " + TextUtils.join(", ", phone);
    List<Hotel> latitude = datasource.getHotelLat(hotelName);
    final String lat = latitude.get(0).toString();
    List<Hotel> longitude = datasource.getHotelLon(hotelName);
    final String lon = longitude.get(0).toString();
    List<Hotel> photo = datasource.getHotelPhoto(hotelName);
    final String pho = photo.get(0).toString();
    //Toast.makeText(hotelSearchList.this, "The hotel clicked is " + hotelName, Toast.LENGTH_LONG).show();
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Information About " + hotelName);
    builder.setMessage(loc + "\n" + add + "\n" + rat + "\n" + phoneN + "\n");

    builder.setPositiveButton("Call", new DialogInterface.OnClickListener() {

        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            Intent i = new Intent(Intent.ACTION_DIAL, Uri.parse("tel:" + phoneN));
            startActivity(i);
        }
    });
    builder.setNegativeButton("View Photo", new DialogInterface.OnClickListener() {

        public void onClick(DialogInterface dialog, int which) {
            // TODO Auto-generated method stub
            Intent i = new Intent(hotelSearchList.this, imageV.class);
            i.putExtra("photo", pho);
            startActivity(i);
        }
    });
    builder.setNeutralButton("Map it", new DialogInterface.OnClickListener() {

        public void onClick(DialogInterface arg0, int arg1) {
            // TODO Auto-generated method stub
            Intent i = new Intent(hotelSearchList.this, mapActivity.class);
            i.putExtra("latitude", lat);
            i.putExtra("longitude", lon);
            startActivity(i);
        }
    });

    builder.setCancelable(true);
    builder.show();
    return false;
}

这是日志猫：

04-28 19:47:15.159: E/AndroidRuntime(384): FATAL EXCEPTION: main
04-28 19:47:15.159: E/AndroidRuntime(384): java.lang.NullPointerException
04-28 19:47:15.159: E/AndroidRuntime(384):  at egypt.interfaceAct.touristicASearchList.onItemLongClick(touristicASearchList.java:134)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.widget.AbsListView.performLongPress(AbsListView.java:1753)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.widget.AbsListView.access$600(AbsListView.java:72)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.widget.AbsListView$CheckForLongPress.run(AbsListView.java:1711)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.os.Handler.handleCallback(Handler.java:587)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.os.Handler.dispatchMessage(Handler.java:92)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.os.Looper.loop(Looper.java:123)
04-28 19:47:15.159: E/AndroidRuntime(384):  at android.app.ActivityThread.main(ActivityThread.java:4627)
04-28 19:47:15.159: E/AndroidRuntime(384):  at java.lang.reflect.Method.invokeNative(Native Method)
04-28 19:47:15.159: E/AndroidRuntime(384):  at java.lang.reflect.Method.invoke(Method.java:521)
04-28 19:47:15.159: E/AndroidRuntime(384):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
04-28 19:47:15.159: E/AndroidRuntime(384):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
04-28 19:47:15.159: E/AndroidRuntime(384):  at dalvik.system.NativeStart.main(Native Method)
4

2 回答 2

0

前 8 次您可能是指无需滚动即可显示在屏幕上的项目，对吧？

您需要发布一些代码以便我们为您提供帮助。

于 2012-04-28T16:40:44.940 回答
0

onItemLongClick()这是设置一些断点和使用调试器的绝佳时机。它将帮助您找到空值或至少找到它崩溃的行。

我愿意猜测对话框打开的次数无关紧要，我假设您的第 8 个条目是无效的。如果您先单击第 8 个条目，它仍然会崩溃吗？如果是这样，您检查您的数据库，第 8 行是否hotelName包含您请求的所有字段，或者一个（或多个）列是否具有空值？

添加

当列表滚动并使用此行时：

String hotelName = (String) ((TextView)parent.getChildAt(position)).getText();

该位置超出范围，返回null导致您的 NullPointerException 因为父级的唯一子级是可见的，而是尝试更快、更简单的方法：

String hotelname = ((TextView) view).getText().toString();
于 2012-04-28T17:11:37.860 回答