I'm currently working on a task reminder app that makes use of a custom calendar where reminders (i.e tasks) are stored. But for some reason, this error pops up...
java.lang.NullPointerException: Attempt to invoke interface method 'int java.util.List.size()' on
a null object reference
at com.example.projecttweeta.MyGridAdapter.getView(MyGridAdapter.java:78)
at android.widget.AbsListView.obtainView(AbsListView.java:2387)
at android.widget.GridView.onMeasure(GridView.java:1085)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1204)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:723)
at android.view.View.measure(View.java:25466)
at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:792)
at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.measure(BasicMeasure.java:480)
at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.measureChildren(BasicMeasure.java:134)
at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:277)
at androidx.constraintlayout.solver.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:119)
at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1578)
at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1690)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at androidx.appcompat.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:146)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at androidx.appcompat.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:490)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
at android.view.View.measure(View.java:25466)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6957)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
at com.android.internal.policy.DecorView.onMeasure(DecorView.java:747)
at android.view.View.measure(View.java:25466)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:3397)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:2228)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2486)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1952)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8171)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:972)
at android.view.Choreographer.doCallbacks(Choreographer.java:796)
at android.view.Choreographer.doFrame(Choreographer.java:731)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:957)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
Its coming from this particular Java class...
package com.example.projecttweeta;
import android.content.Context;
import android.graphics.Color;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Locale;
public class MyGridAdapter extends ArrayAdapter {
List<Date> dates;
Calendar currentDate;
List<Tasks> tasks;
LayoutInflater inflater;
public MyGridAdapter(@NonNull Context context, List<Date> dates, Calendar currentDate, List<Tasks> tasks) {
super(context, R.layout.single_cell_layout); // work on that after this...
this.dates = dates;
this.currentDate = currentDate;
inflater = LayoutInflater.from(context);
}
@Override
public int getCount() {
return dates.size();
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
Date monthDate = dates.get(position);
Calendar dateCalender = Calendar.getInstance();
dateCalender.setTime(monthDate);
int dayNo = dateCalender.get(Calendar.DAY_OF_MONTH);
int displayMonth = dateCalender.get(Calendar.MONTH) + 1;
int displayYear = dateCalender.get(Calendar.YEAR);
int currentMonth = currentDate.get(Calendar.MONTH) + 1;
int currentYear = currentDate.get(Calendar.YEAR);
View view = convertView;
if (view == null) {
view = inflater.inflate(R.layout.single_cell_layout, parent, false);
}
if (displayMonth == currentMonth && displayYear == currentYear) {
// view.setBackgroundColor(getContext().getResources().getColor(R.color.color_primary));
view.setBackgroundColor(Color.parseColor("#60DDED"));
} else {
// view.setBackgroundColor(Color.parseColor("#D3D3D3"));
view.setBackgroundColor(Color.TRANSPARENT);
}
TextView day_number = view.findViewById(R.id.calender_day);
TextView task_number = view.findViewById(R.id.task_id);
day_number.setText(String.valueOf(dayNo));
Calendar taskCalender = Calendar.getInstance();
ArrayList<String> arrayList = new ArrayList<>();
for (int i = 0; 1 < tasks.size(); i++ ) {
taskCalender.setTime(convertStringToDate(tasks.get(i).getDATE()));
if (dayNo == taskCalender.get(Calendar.DAY_OF_MONTH) && displayMonth == taskCalender.get(Calendar.MONTH) + 1
&& displayYear == taskCalender.get(Calendar.YEAR)) {
arrayList.add(tasks.get(i).getTITLE());
task_number.setText(arrayList.size() + " Tasks");
}
}
return view;
}
private Date convertStringToDate(String taskDate) {
SimpleDateFormat format = new SimpleDateFormat("yyy-MM-dd", Locale.ENGLISH);
Date date = null;
try {
date = format.parse(taskDate);
} catch (ParseException e) {
e.printStackTrace();
}
return date;
}
@Override
public int getPosition(@Nullable Object item) {
return dates.indexOf(item);
}
@Nullable
@Override
public Object getItem(int position) {
return dates.get(position);
}
}
Please I need a response as soon as possible thanks. If you need the remaining codes, that would be fine.
