Cant adds new object to RealmList due to null object reference
I have realm objects, one of which is a basic RealmObject with two strings and a boolean, and the other is just a RealmList for that object for easier access. When I try to get a list from my ContactBook instance and add a new object, I get an attempt to call a virtual method with a null object reference. However, I can get the size of the contact book and the number of contacts so that they are not null.
Class Where I am trying to add new objects
public void viewSetup() {
setContentView(R.layout.activity_contacts);
ButterKnife.inject(this);
Realm.deleteRealmFile(this);
realm = Realm.getInstance(this);
results = realm.where(ContactBook.class).findAll();
if (toolbar != null) {
setSupportActionBar(toolbar);
}
if (results.size() == 0) {
realm.beginTransaction();
ContactBook contactBook = realm.copyToRealm(new ContactBook());
realm.commitTransaction();
}
}
public void setupCursor() {
Cursor cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, null);
ContactBook contactBook = results.first();
realm.beginTransaction();
while (cursor.moveToNext()) {
String name = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
if (contactBook.getContacts().where().equalTo("name", name).findAll().size() == 0 && contactBook.getContacts().where().equalTo("number", number).findAll().size() == 0) {
contactBook.getContacts().add(new Contact(name, number, false));
}
}
realm.commitTransaction();
cursor.close();
}
class with two strings and boolean
public class Contact extends RealmObject {
private String name;
private String number;
private boolean allowed;
public Contact() {
}
public Contact(String name, String number, boolean allowed) {
this.name = name;
this.number = number;
this.allowed = allowed;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getNumber() {
return number;
}
public void setNumber(String number) {
this.number = number;
}
public boolean isAllowed() {
return allowed;
}
public void setAllowed(boolean allowed) {
this.allowed = allowed;
}
}
Contact book class
public class ContactBook extends RealmObject {
private RealmList<Contact> contacts = new RealmList<>();
public ContactBook() {
}
public RealmList<Contact> getContacts() {
return contacts;
}
public void setContacts(RealmList<Contact> contactBook) {
this.contacts = contactBook;
}
}
Error log
java.lang.RuntimeException: Unable to start activity ComponentInfo{io.github.brady131313.textback/io.github.brady131313.textback.View.ActivityContactSelect}: java.lang.NullPointerException: Attempt to invoke virtual method 'long io.realm.internal.Row.getIndex()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2661)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1421)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5835)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1388)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'long io.realm.internal.Row.getIndex()' on a null object reference
at io.realm.RealmList.add(RealmList.java:122)
at io.github.brady131313.textback.View.ActivityContactSelect.setupCursor(ActivityContactSelect.java:69)
at io.github.brady131313.textback.View.ActivityContactSelect.onCreate(ActivityContactSelect.java:39)
at android.app.Activity.performCreate(Activity.java:6221)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2614)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1421)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5835)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1388)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1183)
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1 answer
This is because you are trying to add a non-managed object to a managed list. This code is here:
if (contactBook.getContacts().where().equalTo("name", name).findAll().size() == 0 && contactBook.getContacts().where().equalTo("number", number).findAll().size() == 0) {
contactBook.getContacts().add(new Contact(name, number, false));
}
it should be:
if (contactBook.getContacts().where().equalTo("name", name).findAll().size() == 0 && contactBook.getContacts().where().equalTo("number", number).findAll().size() == 0) {
Contact newContact = realm.copyToRealm(new Contact(name, number, false));
contactBook.getContacts().add(newContact);
}
Objects created with an operator new
cannot be added to RealmLists that are already in Realm without using one of the methods Realm.copyToRealmXXX
, because it must first be converted to a valid (or managed) Realm object. But the error message could be better.
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