我正在为我的应用程序获取这些空指针异常崩溃。出于某种奇怪的原因，它们只发生在三星手机上。不知道发生了什么。我的代码似乎很扎实。任何帮助非常感谢。
我已经阅读了有关nullpointerexceptions的文档以及如何找到它们，但这个真的让我难过。从堆栈跟踪中，我查看了引用的行，但似乎无法在这些位置找到对null的引用。
编辑：这是不同的，因为空指针指南链接，我已经读过了。我的代码中没有空引用。
这是崩溃信息：
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'long java.util.Date.getTime()' on a null object reference
at java.util.Calendar.setTime(Calendar.java:1197)
at java.text.SimpleDateFormat.formatImpl(SimpleDateFormat.java:527)
at java.text.SimpleDateFormat.format(SimpleDateFormat.java:829)
at java.text.DateFormat.format(DateFormat.java:314)
at com.myapp.mapapp.helper.Utilities.getEvents(Utilities.java:108)
at com.myapp.mapapp.CalenderEventsActivity.onCreate(CalenderEventsActivity.java:125)
at android.app.Activity.performCreate(Activity.java:6876)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1135)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3206)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3349)
at android.app.ActivityThread.access$1100(ActivityThread.java:221)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1794)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7224)
at java.lang.reflect.Method.invoke(Method.java)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
这是第一个引发它的java文件：
/**
* Created by data intelligence labs on 1/8/2017.
*/
public class Utilities {
@ColorInt
public static int getThemeColor(@NonNull final Context context, @AttrRes final int attributeColor)
{
final TypedValue value = new TypedValue();
context.getTheme ().resolveAttribute (attributeColor, value, true);
return value.data;
}
public static CalendarDay toCalendar(Date date){
Calendar cal = Calendar.getInstance();
cal.setTime(date);
return CalendarDay.from(cal);
}
public static int GetRandomNumber(){
return (int) ((new Date().getTime() / 1000L) % Integer.MAX_VALUE);
}
public static Date ParseDate(String dateString, SimpleDateFormat format){
Date date=null;
try {
date = format.parse(dateString);
} catch (Exception e) {
Log.e("",e.toString());
}
return date;
}
public static Date addDays(Date date, int days, int months, int year)
{
Calendar cal = Calendar.getInstance();
cal.setTime(date);
cal.add(Calendar.DATE, days); //minus number would decrement the days
cal.add(Calendar.MONTH, months);
cal.add(Calendar.YEAR, year);
return cal.getTime();
}
public static String ReadFromfile(String fileName, Context context) {
StringBuilder returnString = new StringBuilder();
BufferedReader reader = null;
try {
reader = new BufferedReader(
new InputStreamReader(context.getAssets().open(fileName), "UTF-8"));
// do reading, usually loop until end of file reading
String mLine;
while ((mLine = reader.readLine()) != null) {
//process line
returnString.append(mLine + "\n");
}
} catch (IOException e) {
//log the exception
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
//log the exception
}
}
}
return returnString.toString();
}
public static Map<String, ArrayList<OtherEvents>> getEvents(Context content, SimpleDateFormat dateFormatString) {
Map<String, ArrayList<OtherEvents>> map= new ArrayMap<String, ArrayList<OtherEvents>>();
{
String lunar_file = ReadFromfile("lunar_eclipse.txt", content);
String lunar_lines[] = lunar_file.split("\\r?\\n");
SimpleDateFormat format = new SimpleDateFormat("dd-MMM-yy");
//format.setTimeZone(TimeZone.getTimeZone("GMT"));
for (String line: lunar_lines){
String[] line_parts = line.split(",");
Date date= Utilities.ParseDate(line_parts[0],format);
OtherEvents s= new OtherEvents();
s.Date=date;
s.Type=line_parts[2];
s.EventType= EventTypes.LunarEclipse;
String date_string = dateFormatString.format(date);
if (map.containsKey(date_string)){
map.get(date_string).add(s);
}
else{
ArrayList<OtherEvents> ar = new ArrayList<>();
ar.add(s);
map.put(date_string,ar);
}
}
}
{
String lunar_file = ReadFromfile("full_moon.txt", content);
String lunar_lines[] = lunar_file.split("\\r?\\n");
SimpleDateFormat format = new SimpleDateFormat("MMM dd, yyyy");
//format.setTimeZone(TimeZone.getTimeZone("GMT"));
for (String line: lunar_lines){
String[] line_parts = line.split("\\|");
Date date=Utilities.ParseDate(line_parts[0].trim(),format);
OtherEvents s= new OtherEvents();
s.Date=date;
if (line_parts.length>3){
s.Type=line_parts[3].trim();
}
else{
s.Type="";
}
s.EventType= EventTypes.FullMoon;
String date_string = dateFormatString.format(date);
if (map.containsKey(date_string)){
map.get(date_string).add(s);
}
else{
ArrayList<OtherEvents> ar = new ArrayList<>();
ar.add(s);
map.put(date_string,ar);
}
}
}
{
String lunar_file = ReadFromfile("meteor.txt", content);
String lunar_lines[] = lunar_file.split("\\r?\\n");
SimpleDateFormat format = new SimpleDateFormat("dd-MMM-yyyy");
//format.setTimeZone(TimeZone.getTimeZone("GMT"));
for (String line: lunar_lines){
String[] line_parts = line.split("\\|");
Date startDate=Utilities.ParseDate(line_parts[1].trim(),format);
Date endDate=Utilities.ParseDate(line_parts[2].trim(),format);
Date peakDate=Utilities.ParseDate(line_parts[3].trim(),format);
for (int j=0;j<=50;j++){
startDate = Utilities.addDays(startDate,0,0,1);
endDate = Utilities.addDays(endDate,0,0,1);
peakDate = Utilities.addDays(peakDate,0,0,1);
long diff = endDate.getTime() - startDate.getTime();
long days = TimeUnit.DAYS.convert(diff, TimeUnit.MILLISECONDS);
for (int d=0;d<=days;d++){
Date currentDate = Utilities.addDays(startDate, d,0,0);
String date_string = dateFormatString.format(currentDate);
OtherEvents s= new OtherEvents();
s.Date= (Date) peakDate.clone();
s.MeterorStartDate= (Date) startDate.clone();
s.MeterorEndDate = (Date) endDate.clone();
s.Type=line_parts[0];
if (currentDate.compareTo(peakDate)==0){
s.Type=line_parts[0].toString() + " - Peak";
}
s.EventType= EventTypes.MeteorShower;
if (map.containsKey(date_string)){
map.get(date_string).add(s);
}
else{
ArrayList<OtherEvents> ar = new ArrayList<>();
ar.add(s);
map.put(date_string,ar);
}
}
}
}
}
return map;
}
}
这是它引用的第二个java文件：
public class CalenderEventsActivity extends AppCompatActivity implements OnDateSelectedListener,AdapterView.OnItemClickListener{
static final String LOG_TAG = CalenderEventsActivity.class.getSimpleName();
static final SimpleDateFormat DATE_TIME_FORMAT = new SimpleDateFormat("dd-MMM-yy");
private final OneDayDecorator oneDayDecorator = new OneDayDecorator();
private ListView listView;
private ArrayAdapter adapter;
private ArrayList<OtherEvents> eventsList;
@Bind(R.id.calendarView)
MaterialCalendarView widget;
private static Map<String, ArrayList<OtherEvents>> map = new HashMap<String, ArrayList<OtherEvents>>();
//Ads
private PurchaseHelper mPurchases1;
private AdView mAdView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_calender_events);
widget = (MaterialCalendarView) findViewById(R.id.calendarView);
mPurchases1 = PurchaseHelper.createInstance();
initAds();
updatePro();
ButterKnife.bind(this);
try
{
Log.i(LOG_TAG,CalenderEventsActivity.this.toString());
widget.setOnDateChangedListener(CalenderEventsActivity.this);
}
catch (Exception e){
Log.e(LOG_TAG,e.toString());
}
widget.setShowOtherDates(MaterialCalendarView.SHOW_ALL);
Calendar instance = Calendar.getInstance();
if (getIntent().getStringExtra("date")!=null){
widget.setSelectedDate(Utilities.ParseDate(getIntent().getStringExtra("date"),DATE_TIME_FORMAT));
}
else {
widget.setSelectedDate(instance.getTime());
}
Calendar instance1 = Calendar.getInstance();
instance1.set(2016, Calendar.JANUARY, 1);
Calendar instance2 = Calendar.getInstance();
instance2.set(2049, Calendar.DECEMBER, 31);
widget.state().edit()
.setMinimumDate(instance1.getTime())
.setMaximumDate(instance2.getTime())
.commit();
widget.addDecorators(
new CalenderEventSelectorDecorator(this),
new HighlightWeekendsDecorator(),
oneDayDecorator
);
//new ApiSimulator().executeOnExecutor(Executors.newSingleThreadExecutor());
listView=(ListView)findViewById(R.id.lst_calender_events);
listView.setOnItemClickListener(this);
/*
listView.setOnClickListener(new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getBaseContext(),parent.getItemAtPosition(position)+" is selected",Toast.LENGTH_LONG).show();
}
});
*/
if (map.size()==0){
map = Utilities.getEvents(this, DATE_TIME_FORMAT);
Log.i(LOG_TAG,Integer.toString(map.size()));
}
ArrayList<CalendarDay> eventDays= new ArrayList<CalendarDay>();
Set<String> eventDates = map.keySet();
for(String date: eventDates){
eventDays.add(Utilities.toCalendar(Utilities.ParseDate(date,DATE_TIME_FORMAT)));
}
widget.addDecorator(new EventDecorator(ContextCompat.getColor(this, R.color.colorNotification), eventDays));
dateSelected(widget.getSelectedDate());
//Show notification
if (getIntent().getSerializableExtra("event")!=null){
OtherEvents selectedItem = (OtherEvents) getIntent().getSerializableExtra("event");
ArrayList<OtherEvents> params = new ArrayList<>();
OtherEvents param = (OtherEvents) selectedItem.clone();
param.showButtonContainer = false;
param.remainingDaysString = "";
params.add(param);
FragmentManager fm = getSupportFragmentManager();
for(Iterator<OtherEvents> i = params.iterator(); i.hasNext(); ) {
OtherEvents item = i.next();
AlertDialogFragment alertDialog = AlertDialogFragment.newInstance(item);
alertDialog.setCancelable(true);
alertDialog.show(fm, "fragment_alert");
alertDialog.setOnFragDismissedListener(new AlertDialogFragment.OnDialogFragHide() {
@Override
public void onFragmentDismissed() {
Log.i(LOG_TAG,"alert fragment dismissed");
}
});
}
}
}
private void initAds() {
// Request for Ads
AdRequest adRequest = new AdRequest.Builder()
// Add a test device to show Test Ads
.addTestDevice(AdRequest.DEVICE_ID_EMULATOR)
.addTestDevice("CEDB1558F8E15156FAB8EF79CEC9C253")
.build();
//Locate the Banner Ad in activity_main.xml
mAdView = (AdView) this.findViewById(R.id.adView);
// Load ads into Banner Ads
mAdView.loadAd(adRequest);
}
private void updatePro() {
Boolean mIsPaid = !mPurchases1.showPurchaseDialog();
FrameLayout layout = (FrameLayout)findViewById(R.id.ads_layout);
if (mIsPaid) {
if (layout!=null)
layout.setVisibility(View.GONE);
if (mAdView!=null)
mAdView.pause();
}
else{
if (layout!=null)
layout.setVisibility(View.VISIBLE);
if (mAdView!=null)
mAdView.resume();
}
}
@Override
public void onDateSelected(@NonNull MaterialCalendarView widget, @NonNull CalendarDay date, boolean selected) {
//If you change a decorate, you need to invalidate decorators
oneDayDecorator.setDate(date.getDate());
widget.invalidateDecorators();
dateSelected(date);
}
private void dateSelected(CalendarDay date) {
adapter = new AppEventsAdapter(this, R.layout.calendar_event_item_template); // the adapter is a member field in the activity
//setContentView(R.layout.activity_view_memo_layout);
ListView lv = (ListView) findViewById(R.id.lst_calender_events);
lv.setAdapter(adapter);
eventsList = new ArrayList<OtherEvents>(); //here you should use a list with some content in it
String date_string = DATE_TIME_FORMAT.format(date.getDate());
if (map.containsKey(date_string))
{
eventsList = map.get(date_string);
}
adapter.addAll(eventsList);
}
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Log.i(LOG_TAG,"show dialog window");
OtherEvents selectedItem = eventsList.get(position);
ArrayList<OtherEvents> params = new ArrayList<OtherEvents>();
OtherEvents param = (OtherEvents) selectedItem.clone();
param.showButtonContainer = false;
param.remainingDaysString = "";
params.add(param);
FragmentManager fm = getSupportFragmentManager();
for(Iterator<OtherEvents> i = params.iterator(); i.hasNext(); ) {
OtherEvents item = i.next();
AlertDialogFragment alertDialog = AlertDialogFragment.newInstance(item);
alertDialog.setCancelable(true);
alertDialog.show(fm, "fragment_alert");
alertDialog.setOnFragDismissedListener(new AlertDialogFragment.OnDialogFragHide() {
@Override
public void onFragmentDismissed() {
Log.i(LOG_TAG,"alert fragment dismissed");
}
});
}
}
/**
* Simulate an API call to show how to add decorators
*/
private class ApiSimulator extends AsyncTask<Void, Void, List<CalendarDay>> {
@Override
protected List<CalendarDay> doInBackground(@NonNull Void... voids) {
try {
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.MONTH, -2);
ArrayList<CalendarDay> dates = new ArrayList<>();
for (int i = 0; i < 30; i++) {
CalendarDay day = CalendarDay.from(calendar);
dates.add(day);
calendar.add(Calendar.DATE, 5);
}
return dates;
}
@Override
protected void onPostExecute(@NonNull List<CalendarDay> calendarDays) {
super.onPostExecute(calendarDays);
if (isFinishing()) {
return;
}
widget.addDecorator(new EventDecorator(ContextCompat.getColor(getApplicationContext(), R.color.colorNotification), calendarDays));
}
}
@Override
public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
super.onSaveInstanceState(outState, outPersistentState);
}
}