I am trying to show data one by one in recyclerview from database but application stop working with nullpoint Exception. Here is the detailed code because i am unable to find the mistake. i have tried with stringBuffer but it gets all the data and show all data in a single cardview.
GetterSetterClass.java
public class GetterAndSetterClass {
private String name;
private String details;
public GetterAndSetterClass( String name, String details) {
this.name = name;
this.details = details;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDetails() {
return details;
}
public void setDetails(String details) {
this.details = details;
}
}
cartAdapter.java(AdapterClass being used)
public class cartAdapter extends RecyclerView.Adapter<cartAdapter.cartVewHolder>
{
private ArrayList<GetterAndSetterClass> namesLists;
public cartAdapter(ArrayList<GetterAndSetterClass> namesLists) {
this.namesLists = namesLists;
}
@Override
public cartVewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view= LayoutInflater.from(parent.getContext()).inflate(R.layout.singletext,parent,false);
cartVewHolder cartVewHolder=new cartVewHolder(view);
return cartVewHolder;
}
@Override
public void onBindViewHolder(cartVewHolder holder, int position) {
final GetterAndSetterClass getterAndSetterClass=namesLists.get(position);
holder.textView.setText(getterAndSetterClass.getName());
holder.textView2.setText(getterAndSetterClass.getDetails());
}
@Override
public int getItemCount() {
return namesLists.size();
}
public class cartVewHolder extends RecyclerView.ViewHolder {
TextView textView,textView2;
public cartVewHolder(View itemView) {
super(itemView);
textView=itemView.findViewById(R.id.textviewCard);
textView2=itemView.findViewById(R.id.textview2Card);
}
}
}
cart.java(MainActivity being used)
DatabaseHelperClass databaseHelper;
RecyclerView recyclerView;
GetterAndSetterClass getterAndSetterClass;
cartAdapter cartAdapter;
ArrayList<GetterAndSetterClass> arrayList= new ArrayList<>();
onCreateMethod
recyclerView=findViewById(R.id.cart_recyclerview);
databaseHelper=new DatabaseHelperClass(this);
Cursor cursor=databaseHelper.getAllData();
if (cursor!=null && cursor.getCount()>0){
while (cursor.moveToNext()){
getterAndSetterClass.setName(cursor.getString(1)+"\n");
getterAndSetterClass.setDetails(cursor.getString(2)+"\n\n");
}
arrayList.add(getterAndSetterClass);
}
else {
Toast.makeText(getApplicationContext(),"No Data to retrived",Toast.LENGTH_SHORT).show();
}
recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
cartAdapter=new cartAdapter(arrayList);
recyclerView.setAdapter(cartAdapter);
Error Log
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.uzairmughal.parcelable/com.example.uzairmughal.parcelable.Cart}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2338)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388)
at android.app.ActivityThread.access$900(ActivityThread.java:148)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1319)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5494)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:875)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:691)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.uzairmughal.parcelable.Cart.onCreate(Cart.java:42)
at android.app.Activity.performCreate(Activity.java:5234)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2302)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2388)
at android.app.ActivityThread.access$900(ActivityThread.java:148)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1319)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:5494)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:875)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:691)
at dalvik.system.NativeStart.main(Native Method)
Application terminated.
You need to handle the null
case before calling size()
method on your list namesLists.size()
change your adapter getItemCount()
with below code
@Override
public int getItemCount() {
if(namesLists!=null)
return namesLists.size();
else
return 0;
}
You are not creating a object of GetterAndSetterClass
and setting the values to getterAndSetterClass
use this code
while (cursor.moveToNext()){
GetterAndSetterClass getterAndSetterClass = new GetterAndSetterClass(cursor.getString(1),cursor.getString(2));
arrayList.add(getterAndSetterClass);
}