我的应用程序有问题，它显示了一个网格视图/日历并在一个列表中。在加载此片段时进行调试时会崩溃，并且会出现 logcat。这是我的代码：
public class Fragment3 extends ListFragment implements OnClickListener
{
private static final String tag = "SimpleCalendarViewActivity";
private ImageView calendarToJournalButton;
private Button selectedDayMonthYearButton;
private Button currentMonth;
private ImageView prevMonth;
private ImageView nextMonth;
private GridView calendarView;
private GridCellAdapter adapter;
private Calendar _calendar;
private int month, year;
private final DateFormat dateFormatter = new DateFormat();
private static final String dateTemplate = "MMMM yyyy";
ArrayList<HashMap<String, String>> menuItems = new ArrayList<HashMap<String, String>>();
// All static variables
static final String URL = "http://www.testtesttest.netsons.org/Calendario.xml";
// XML node keys
static final String KEY_ITEM = "item";
static final String KEY_ID = "ID";
static final String KEY_DATA = "data";
static final String KEY_TESTO = "testo";// parent node
ListView list;
/** Called when the activity is first created. */
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//CALENDARIO
_calendar = Calendar.getInstance(Locale.ITALIAN);
month = _calendar.get(Calendar.MONTH) + 1;
year = _calendar.get(Calendar.YEAR);
Log.d(tag, "Calendar Instance:= " + "Month: " + month + " " + "Year: " + year);
/* selectedDayMonthYearButton = (Button) this.findViewById(R.id.selectedDayMonthYear);
selectedDayMonthYearButton.setText("Selected: ");
*/
prevMonth = (ImageView)this.getActivity().findViewById(R.id.prevMonth);
// prevMonth.setOnClickListener();
currentMonth = (Button)this.getActivity().findViewById(R.id.currentMonth);
// currentMonth.setText(dateFormatter.format(dateTemplate, _calendar.getTime()));
nextMonth = (ImageView)this.getActivity().findViewById(R.id.nextMonth);
// nextMonth.setOnClickListener(this);
calendarView = (GridView)this.getActivity().findViewById(R.id.calendar);
// Initialised
adapter = new GridCellAdapter(getActivity().getApplicationContext(), R.id.calendar_day_gridcell, month, year);
adapter.notifyDataSetChanged();
calendarView.setAdapter(adapter);
//LISTA
XMLParser parser = new XMLParser();
String xml = parser.getXmlFromUrl(URL); // getting XML
Document doc = parser.getDomElement(xml); // getting DOM element
NodeList nl = doc.getElementsByTagName(KEY_ITEM);
// 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_ID, parser.getValue(e, KEY_ID));
map.put(KEY_DATA, parser.getValue(e, KEY_DATA));
map.put(KEY_TESTO, parser.getValue(e, KEY_TESTO));
// adding HashList to ArrayList
menuItems.add(map);
}
// Adding menuItems to ListView
ListAdapter adapter = new SimpleAdapter(getActivity(), menuItems,R.layout.listcalendar,new String[] { KEY_DATA, KEY_TESTO }, new int[] {R.id.data, R.id.testo });
setListAdapter(adapter);
View V =inflater.inflate(R.layout.simple_calendar_view,null);
list=(ListView)V.findViewById(android.R.id.list);
// Getting adapter by passing xml data ArrayList
// selecting single ListView item
// listening to single listitem click
list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
/* String not = ((TextView) view.findViewById(R.id.not)).getText().toString();
String testo = ((TextView) view.findViewById(R.id.testo)).getText().toString();
// Starting new intent
Intent in = new Intent(getActivity().getApplicationContext(), ImageGridActivity.class);
in.putExtra(KEY_NOT, not);
in.putExtra(KEY_TESTO, testo);
getActivity().startActivity(in);
*/ }
});
return inflater.inflate(R.layout.simple_calendar_view, container, false);
}
/*
*
* @param month
* @param year
*/
private void setGridCellAdapterToDate(int month, int year)
{
adapter = new GridCellAdapter(getActivity(), R.id.calendar_day_gridcell, month, year);
_calendar.set(year, month - 1, _calendar.get(Calendar.DAY_OF_MONTH));
currentMonth.setText(dateFormatter.format(dateTemplate, _calendar.getTime()));
adapter.notifyDataSetChanged();
calendarView.setAdapter(adapter);
}
@Override
public void onClick(View v)
{
if (v == prevMonth)
{
if (month <= 1)
{
month = 12;
year--;
}
else
{
month--;
}
Log.d(tag, "Setting Prev Month in GridCellAdapter: " + "Month: " + month + " Year: " + year);
setGridCellAdapterToDate(month, year);
}
if (v == nextMonth)
{
if (month > 11)
{
month = 1;
year++;
}
else
{
month++;
}
Log.d(tag, "Setting Next Month in GridCellAdapter: " + "Month: " + month + " Year: " + year);
setGridCellAdapterToDate(month, year);
}
}
@Override
public void onDestroy()
{
Log.d(tag, "Destroying View ...");
super.onDestroy();
}
// ///////////////////////////////////////////////////////////////////////////////////////
// Inner Class
public class GridCellAdapter extends BaseAdapter implements OnClickListener
{
private static final String tag = "GridCellAdapter";
private final Context _context;
private final List<String> list;
private static final int DAY_OFFSET = 1;
private final String[] weekdays = new String[]{"Lun", "Mar", "Mer", "Gio", "Ven", "Sab", "Dom"};
private final String[] months = {"Gennaio", "Febbraio", "Marzo", "Aprile", "Maggio", "Giugno", "Luglio", "Agosto", "Settembre", "Ottobre", "Novembre", "Dicembre"};
private final int[] daysOfMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
private final int month, year;
private int daysInMonth, prevMonthDays;
private int currentDayOfMonth;
private int currentWeekDay;
private Button gridcell;
private TextView num_events_per_day;
private final HashMap eventsPerMonthMap;
private final SimpleDateFormat dateFormatter = new SimpleDateFormat("dd-MMM-yyyy");
// Days in Current Month
public GridCellAdapter(Context context, int textViewResourceId, int month, int year)
{
super();
this._context = context;
this.list = new ArrayList<String>();
this.month = month;
this.year = year;
Log.d(tag, "==> Passed in Date FOR Month: " + month + " " + "Year: " + year);
Calendar calendar = Calendar.getInstance();
setCurrentDayOfMonth(calendar.get(Calendar.DAY_OF_MONTH));
setCurrentWeekDay(calendar.get(Calendar.DAY_OF_WEEK));
Log.d(tag, "New Calendar:= " + calendar.getTime().toString());
Log.d(tag, "CurrentDayOfWeek :" + getCurrentWeekDay());
Log.d(tag, "CurrentDayOfMonth :" + getCurrentDayOfMonth());
// Print Month
printMonth(month, year);
// Find Number of Events
eventsPerMonthMap = findNumberOfEventsPerMonth(year, month);
}
private String getMonthAsString(int i)
{
return months[i];
}
private String getWeekDayAsString(int i)
{
return weekdays[i];
}
private int getNumberOfDaysOfMonth(int i)
{
return daysOfMonth[i];
}
public String getItem(int position)
{
return list.get(position);
}
@Override
public int getCount()
{
return list.size();
}
/**
* Prints Month
*
* @param mm
* @param yy
*/
private void printMonth(int mm, int yy)
{
Log.d(tag, "==> printMonth: mm: " + mm + " " + "yy: " + yy);
// The number of days to leave blank at
// the start of this month.
int[] weekDaysToTraling = { 6, 0, 1, 2, 3, 4, 5 };
int leadSpaces = 0;
int daysInPrevMonth = 0;
int prevMonth = 0;
int prevYear = 0;
int nextMonth = 0;
int nextYear = 0;
int currentMonth = mm - 1;
String currentMonthName = getMonthAsString(currentMonth);
daysInMonth = getNumberOfDaysOfMonth(currentMonth);
Log.d(tag, "Current Month: " + " " + currentMonthName + " having " + daysInMonth + " days.");
// Gregorian Calendar : MINUS 1, set to FIRST OF MONTH
GregorianCalendar cal = new GregorianCalendar(yy, currentMonth, 1);
Log.d(tag, "Gregorian Calendar:= " + cal.getTime().toString());
if (currentMonth == 11)
{
prevMonth = currentMonth - 1;
daysInPrevMonth = getNumberOfDaysOfMonth(prevMonth);
nextMonth = 0;
prevYear = yy;
nextYear = yy + 1;
Log.d(tag, "*->PrevYear: " + prevYear + " PrevMonth:" + prevMonth + " NextMonth: " + nextMonth + " NextYear: " + nextYear);
}
else if (currentMonth == 0)
{
prevMonth = 11;
prevYear = yy - 1;
nextYear = yy;
daysInPrevMonth = getNumberOfDaysOfMonth(prevMonth);
nextMonth = 1;
Log.d(tag, "**--> PrevYear: " + prevYear + " PrevMonth:" + prevMonth + " NextMonth: " + nextMonth + " NextYear: " + nextYear);
}
else
{
prevMonth = currentMonth - 1;
nextMonth = currentMonth + 1;
nextYear = yy;
prevYear = yy;
daysInPrevMonth = getNumberOfDaysOfMonth(prevMonth);
Log.d(tag, "***---> PrevYear: " + prevYear + " PrevMonth:" + prevMonth + " NextMonth: " + nextMonth + " NextYear: " + nextYear);
}
// Compute how much to leave before before the first day of the
// month.
// getDay() returns 0 for Sunday.
int currentWeekDay = cal.get(Calendar.DAY_OF_WEEK) - 1;
int trailingSpaces = weekDaysToTraling[currentWeekDay];
Log.d(tag, "Week Day:" + currentWeekDay + " is " + getWeekDayAsString(currentWeekDay));
Log.d(tag, "No. Trailing space to Add: " + trailingSpaces);
Log.d(tag, "No. of Days in Previous Month: " + daysInPrevMonth);
if (cal.isLeapYear(cal.get(Calendar.YEAR)) && mm == 1)
{
++daysInMonth;
}
// Trailing Month days
for (int i = 0; i < trailingSpaces; i++)
{
Log.d(tag, "PREV MONTH:= " + prevMonth + " => " + getMonthAsString(prevMonth) + " " + String.valueOf((daysInPrevMonth - trailingSpaces + DAY_OFFSET) + i));
list.add(String.valueOf((daysInPrevMonth - trailingSpaces + DAY_OFFSET) + i) + "-GREY" + "-" + getMonthAsString(prevMonth) + "-" + prevYear);
}
// Current Month Days
for (int i = 1; i <= daysInMonth; i++)
{
Log.d(currentMonthName, String.valueOf(i) + " " + getMonthAsString(currentMonth) + " " + yy);
if (i == getCurrentDayOfMonth())
{
list.add(String.valueOf(i) + "-BLUE" + "-" + getMonthAsString(currentMonth) + "-" + yy);
}
else
{
list.add(String.valueOf(i) + "-WHITE" + "-" + getMonthAsString(currentMonth) + "-" + yy);
}
}
// Leading Month days
for (int i = 0; i < list.size() % 7; i++)
{
Log.d(tag, "NEXT MONTH:= " + getMonthAsString(nextMonth));
list.add(String.valueOf(i + 1) + "-GREY" + "-" + getMonthAsString(nextMonth) + "-" + nextYear);
}
}
/**
* NOTE: YOU NEED TO IMPLEMENT THIS PART Given the YEAR, MONTH, retrieve
* ALL entries from a SQLite database for that month. Iterate over the
* List of All entries, and get the dateCreated, which is converted into
* day.
*
* @param year
* @param month
* @return
*/
private HashMap findNumberOfEventsPerMonth(int year, int month)
{
HashMap map = new HashMap<String, Integer>();
// DateFormat dateFormatter2 = new DateFormat();
//
// String day = dateFormatter2.format("dd", dateCreated).toString();
//
// if (map.containsKey(day))
// {
// Integer val = (Integer) map.get(day) + 1;
// map.put(day, val);
// }
// else
// {
// map.put(day, 1);
// }
return map;
}
@Override
public long getItemId(int position)
{
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
View row = convertView;
if (row == null)
{
LayoutInflater inflater = (LayoutInflater) _context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.calendar_day_gridcell, parent, false);
}
// Get a reference to the Day gridcell
gridcell = (Button) row.findViewById(R.id.calendar_day_gridcell);
gridcell.setOnClickListener(this);
// ACCOUNT FOR SPACING
Log.d(tag, "Current Day: " + getCurrentDayOfMonth());
String[] day_color = list.get(position).split("-");
String theday = day_color[0];
String themonth = day_color[2];
String theyear = day_color[3];
if ((!eventsPerMonthMap.isEmpty()) && (eventsPerMonthMap != null))
{
if (eventsPerMonthMap.containsKey(theday))
{
num_events_per_day = (TextView) row.findViewById(R.id.num_events_per_day);
Integer numEvents = (Integer) eventsPerMonthMap.get(theday);
num_events_per_day.setText(numEvents.toString());
}
}
// Set the Day GridCell
gridcell.setText(theday);
gridcell.setTag(theday + "-" + themonth + "-" + theyear);
Log.d(tag, "Setting GridCell " + theday + "-" + themonth + "-" + theyear);
if (day_color[1].equals("GREY"))
{
gridcell.setTextColor(Color.LTGRAY);
}
if (day_color[1].equals("WHITE"))
{
gridcell.setTextColor(Color.WHITE);
}
if (day_color[1].equals("BLUE"))
{
gridcell.setTextColor(getResources().getColor(R.color.static_text_color));
}
return row;
}
@Override
public void onClick(View view)
{
String date_month_year = (String) view.getTag();
// selectedDayMonthYearButton.setText("Selected: " + date_month_year);
try
{
Date parsedDate = dateFormatter.parse(date_month_year);
Log.d(tag, "Parsed Date: " + parsedDate.toString());
}
catch (ParseException e)
{
e.printStackTrace();
}
}
public int getCurrentDayOfMonth()
{
return currentDayOfMonth;
}
private void setCurrentDayOfMonth(int currentDayOfMonth)
{
this.currentDayOfMonth = currentDayOfMonth;
}
public void setCurrentWeekDay(int currentWeekDay)
{
this.currentWeekDay = currentWeekDay;
}
public int getCurrentWeekDay()
{
return currentWeekDay;
}
}
}
和空指针异常：
calendarView.setAdapter(adapter);
这是日志猫：
java.lang.NullPointerException
at com.example.scoutgo3.Fragment3.onCreateView(Fragment3.java:92)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1460)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:911)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:461)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1064)
at android.support.v4.view.ViewPager.populate(ViewPager.java:911)
at android.support.v4.view.ViewPager$3.run(ViewPager.java:242)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
at android.view.Choreographer.doCallbacks(Choreographer.java:562)
at android.view.Choreographer.doFrame(Choreographer.java:531)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
at android.os.Handler.handleCallback(Handler.java:725)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5041)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
at dalvik.system.NativeStart.main(Native Method)
希望任何人都可以帮助我，因为这个错误非常令人沮丧！！！！谢谢！