我正在尝试过滤代码，目前遇到了一些 NullException 错误。有人可以帮帮我吗？
我想从 URL 源（XML 数据）中获取代码并使用 Spinner 将其过滤掉
示例：微调器：“今天”，“明天” 选择“今天”后，它将显示今天的事件。选择“明天”后，它将显示明天的事件。
但是，我遇到了一些空异常。谁能指导我？
public class AndroidXMLParsingActivity extends ListActivity implements OnItemSelectedListener {
String[] browseby;
Date d = new Date();
String[] dates = { "Today", "Tomorrow", "Next Week",
};
ArrayList<String> browse = new ArrayList<String>();
ArrayList<String> mPostingData = new ArrayList<String>();
Spinner s1;
ListView listview;
CustomAdapter cus;
// All static variables
static final String URL = "http://api.eventful.com/rest/events/search?app_key=42t54cX7RbrDFczc&location=singapore";
// XML node keys
static final String KEY_EVENT = "event"; // parent node
static final String KEY_TITLE = "title";
static final String KEY_START_TIME = "start_time";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();
XMLParser parser = new XMLParser();
String xml = parser.getXmlFromUrl(URL); // getting XML
Document doc = parser.getDomElement(xml); // getting DOM element
NodeList nl = doc.getElementsByTagName(KEY_EVENT);
// looping through all item nodes <item>
for (int i = 0; i < nl.getLength(); i++) {
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
Element e = (Element) nl.item(i);
// adding each child node to HashMap key => value
map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE));
map.put(KEY_START_TIME, parser.getValue(e, KEY_START_TIME));
// adding HashList to ArrayList
menuItems.add(map);
}
// Adding menuItems to ListView
ListAdapter adapter = new SimpleAdapter(this, menuItems,
R.layout.list_item, new String[] { KEY_TITLE,KEY_START_TIME }, new int[] {
R.id.title,
R.id.startTime });
setListAdapter(adapter);
// selecting single ListView item
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String title = ((TextView) view.findViewById(R.id.title))
.getText().toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
SingleMenuItemActivity.class);
in.putExtra(KEY_TITLE, title);
startActivity(in);
}
});
listview = (ListView) findViewById(R.id.listView1);
s1 = (Spinner) findViewById(R.id.spinner1);
for (int i = 0; i < browseby.length; i++) {
browse.add(browseby[i]);
}
// aa = new
// ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,Category);
s1.setOnItemSelectedListener(this);
mPostingData = browse;
for (int i = 0; i < mPostingData.size(); i++) {
if (mPostingData.size() > 0)
Log.i("Datas", mPostingData.get(i));
}
cus = new CustomAdapter(this, 0);
setListAdapter(cus);
ArrayAdapter<String> aa = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, dates);
aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
s1.setAdapter(aa);
}
public void onItemSelected(AdapterView<?> parent, View v, int position,
long id) {
// listview.setFilterText(Category[position]);
String Text = s1.getSelectedItem().toString();
cus.getFilter().filter(Text);
cus.notifyDataSetChanged();
}
public void onNothingSelected(AdapterView<?> parent) {
// listview.setFilterText("");
}
public void onListItemClick(ListView parent, View v, int position, long id) {
Toast.makeText(this, "You have selected " + mPostingData.get(position),
Toast.LENGTH_SHORT).show();
}
class CustomAdapter extends ArrayAdapter<String> {
public void setData(ArrayList<String> mPpst) {
mPostingData = mPpst;// contains class items data.
}
@Override
public Filter getFilter() {
return new Filter() {
@Override
protected void publishResults(CharSequence constraint,
FilterResults start_time) {
if (start_time != null && start_time.count >= 0) {
setData((ArrayList<String>) start_time.values);
} else {
setData(browse);// set original values
}
notifyDataSetInvalidated();
}
@Override
protected FilterResults performFiltering(CharSequence constraint) {
FilterResults result = new FilterResults();
if(constraint=="Today") {
constraint = constraint.toString();
CharSequence s = DateFormat.format("yyyy-MM-dd ", d.getTime());
ArrayList<String> foundItems = new ArrayList<String>();
if (browse != null) {
for (int i = 0; i < browse.size(); i++) {
if (browse.get(i).contains(s)){
System.out.println("My datas" + browse.get(i));
foundItems.add(browse.get(i));
} else {
}
}
}
result.count = foundItems.size();// search results found
// return count
result.values = foundItems;// return values
} else {
result.count = -1;// no search results found
}
return result;
}
};
}
LayoutInflater mInflater;
public CustomAdapter(Context context, int textViewResourceId) {
super(context, textViewResourceId);
// TODO Auto-generated constructor stub
mInflater = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return mPostingData.size();
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder vh;
if (convertView == null) {
vh = new ViewHolder();
convertView = mInflater.inflate(R.layout.row, null);
vh.t1 = (TextView) convertView.findViewById(R.id.textView1);
convertView.setTag(vh);
} else {
// Get the ViewHolder back to get fast access to the TextView
// and the ImageView.
vh = (ViewHolder) convertView.getTag();
}
if (mPostingData.size() > 0)
vh.t1.setText(mPostingData.get(position));
return convertView;
}
}
static class ViewHolder {
TextView t1;
}
}
空异常错误在这里：
for (int i = 0; i < browseby.length; i++) {