android button causing crash [duplicate] - android

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 4 years ago.
I am trying to pass login details to another class so that it can be used to login on my MySQL db (using php) but it is crashing giving me the exception: java.lang.IllegalStateException: Could not execute method for android:onClick
stack trace: {StackTraceElement[0]#5692}
658 10752-10752/uk.ac.abertay.contactslist E/AndroidRuntime: FATAL EXCEPTION: main
Process: uk.ac.abertay.contactslist, PID: 10752
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:6294)
at android.view.View$PerformClick.run(View.java:24770)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:6294) 
at android.view.View$PerformClick.run(View.java:24770) 
at android.os.Handler.handleCallback(Handler.java:790) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6494) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void uk.ac.abertay.contactslist.Login.Logino(uk.ac.abertay.contactslist.LoginDetails)' on a null object reference
at uk.ac.abertay.contactslist.LoginActivity.Loginbutton(LoginActivity.java:40)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
at android.view.View.performClick(View.java:6294) 
at android.view.View$PerformClick.run(View.java:24770) 
at android.os.Handler.handleCallback(Handler.java:790) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6494) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) 
04-26 15:39:34.761 1384-3633/? I/chatty: uid=1041(audioserver) writer identical 8 lines
this is the code for the button
private Login login;
public void Loginbutton(View v) {
/* Get entered fields data. */
String email = field_email.getText().toString();
String password = field_password.getText().toString();
login.Logino(new LoginDetails(email,password));
}
when debugging it will run this and go back to the button and after that it will give the exception and crash
public class LoginDetails {
public String email = "";
public String password = "";
LoginDetails(String e, String p) {
email = e;
password = p;
}
}
this is the code I'm trying to run with the button above
public void Logino(LoginDetails loginDetails) {
LoginTask task = new LoginTask();
task.execute(loginDetails);
}

From your StackTrace
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void uk.ac.abertay.contactslist.Login.Logino(uk.ac.abertay.contactslist.LoginDetails)
The line login.Logino the object login is null, you have to initialize it.
Obs:Please use Java naming conventions with method names starting with low case char.

Related

Passing object parameter to extended AsyncTask class

GoodDay everybody.
I wrote a class which extends AsyncTask.
public class InitTransaction extends AsyncTask<TransactionParameters, Void, String> {
#Override
protected String doInBackground(TransactionParameters... params) {
// I do some stuff here
return result;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
// I do some more stuff
}
}
The class is called with:
TransactionParameters transParams = new TransactionParameters(param1, param2);
InitTransaction initTransaction = new InitTransaction();
initTransaction.execute(transParams);
The problem is that i get an error while passing the object to the task:
[![No method?][1]][1]
Anybody knows where the problem may be?
EDIT
Fixed that problem now I have another one.
As soon as I execute initTransaction.execute(transParams); boom!
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.infovision.elcam_02, PID: 17443
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:389)
at android.view.View.performClick(View.java:6600)
at android.view.View.performClickInternal(View.java:6577)
at android.view.View.access$3100(View.java:781)
at android.view.View$PerformClick.run(View.java:25912)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6923)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:870)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:384)
at android.view.View.performClick(View.java:6600) 
at android.view.View.performClickInternal(View.java:6577) 
at android.view.View.access$3100(View.java:781) 
at android.view.View$PerformClick.run(View.java:25912) 
at android.os.Handler.handleCallback(Handler.java:873) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:193) 
at android.app.ActivityThread.main(ActivityThread.java:6923) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:870) 
Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
at android.view.ViewRootImpl.setView(ViewRootImpl.java:828)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:356)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:93)
at android.app.Dialog.show(Dialog.java:329)
at com.infovision.elcam_02.MainActivity$InitTransaction.onPreExecute(MainActivity.java:242)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:648)
at android.os.AsyncTask.execute(AsyncTask.java:595)
at com.infovision.elcam_02.MainActivity.scanCode(MainActivity.java:133)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:384) 
at android.view.View.performClick(View.java:6600) 
at android.view.View.performClickInternal(View.java:6577) 
at android.view.View.access$3100(View.java:781) 
at android.view.View$PerformClick.run(View.java:25912) 
at android.os.Handler.handleCallback(Handler.java:873) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:193) 
at android.app.ActivityThread.main(ActivityThread.java:6923) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:870) 

My app to know if a file exist in a URL keeps stoping [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 4 years ago.
Im trying to write an app that puts a string in a textview if there is a file in a given url, this is the code and the crash info, what could be the error?.
public class MainActivity extends AppCompatActivity {
String url = "https://images.pexels.com/photos/617278/pexels-photo-617278.jpeg?cs=srgb&dl=adorable-animal-blur-617278.jpg&fm=jpg";
TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView.findViewById(R.id.textView);
try {
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
connection.setRequestMethod("HEAD");
connection.connect();
if(connection.getResponseCode() == HttpURLConnection.HTTP_OK){
textView.setText("File Exists!!");
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.archivoexiste, PID: 6160
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.archivoexiste/com.example.android.archivoexiste.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.widget.TextView.findViewById(int)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6541)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.widget.TextView.findViewById(int)' on a null object reference
at com.example.android.archivoexiste.MainActivity.onCreate(MainActivity.java:23)
at android.app.Activity.performCreate(Activity.java:6975)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892) 
at android.app.ActivityThread.-wrap11(Unknown Source:0) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593) 
at android.os.Handler.dispatchMessage(Handler.java:105) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6541) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767) 
Application terminated.
Change this line in your oncreate method
textView.findViewById(R.id.textView);
to this
textView = (TextView) findViewById(R.id.textView);

What cause the exception ' java.lang.RuntimeException: Failed to call observer method'?

I am writing code to fetch data from a firebase database:
private void displayMessages(){
//Suppose you want to retrieve "chats" in your Firebase DB:
DatabaseReference ref=FirebaseDatabase.getInstance().getReference(Constants.USERS_CHAT).child(chatId);
Log.d(TAG,"Inside query"+ref);
ref.addListenerForSingleValueEvent(new ValueEventListener(){
#Override
public void onDataChange(DataSnapshot dataSnapshot){
Log.d(TAG,"Inside query Inside onDataChange");
if(dataSnapshot.exists()) {
queryforDisplayMessages=mDbRefusers_chat.child(chatId);
}else{
queryforDisplayMessages=mDbRefusers_chat.child(revchatId);
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
But when running it, I get the following exception:
Process: com.iworld.daxi, PID: 20438
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.iworld.daxi/com.iworld.daxi.UserChatActivity}:
java.lang.RuntimeException: Failed to call observer method
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2946)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3046)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1688)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6809)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Caused by: java.lang.RuntimeException: Failed to call observer method
at android.arch.lifecycle.ClassesInfoCache$MethodReference.invokeCallback(ClassesInfoCache.java:225)
at android.arch.lifecycle.ClassesInfoCache$CallbackInfo.invokeMethodsForEvent(ClassesInfoCache.java:193)
at android.arch.lifecycle.ClassesInfoCache$CallbackInfo.invokeCallbacks(ClassesInfoCache.java:184)
at android.arch.lifecycle.ReflectiveGenericLifecycleObserver.onStateChanged(ReflectiveGenericLifecycleObserver.java:36)
at android.arch.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:354)
at android.arch.lifecycle.LifecycleRegistry.forwardPass(LifecycleRegistry.java:292)
at android.arch.lifecycle.LifecycleRegistry.sync(LifecycleRegistry.java:332)
at android.arch.lifecycle.LifecycleRegistry.moveToState(LifecycleRegistry.java:137)
at android.arch.lifecycle.LifecycleRegistry.handleLifecycleEvent(LifecycleRegistry.java:123)
at android.arch.lifecycle.ReportFragment.dispatch(ReportFragment.java:121)
at android.arch.lifecycle.ReportFragment.onStart(ReportFragment.java:81)
at android.app.Fragment.performStart(Fragment.java:2637)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1312)
at android.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1549)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1611)
at android.app.FragmentManagerImpl.dispatchMoveToState(FragmentManager.java:3039)
at android.app.FragmentManagerImpl.dispatchStart(FragmentManager.java:2996)
at android.app.FragmentController.dispatchStart(FragmentController.java:189)
at android.app.Activity.performStart(Activity.java:7021)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2909)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3046) 
at android.app.ActivityThread.-wrap11(Unknown Source:0) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1688) 
at android.os.Handler.dispatchMessage(Handler.java:105) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6809) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.database.ChildEventListener com.google.firebase.database.Query.addChildEventListener(com.google.firebase.database.ChildEventListener)' on a null object reference
at com.firebase.ui.database.FirebaseArray.onCreate(FirebaseArray.java:53)
at com.firebase.ui.common.BaseObservableSnapshotArray.addChangeEventListener(BaseObservableSnapshotArray.java:97)
at com.firebase.ui.database.FirebaseListAdapter.startListening(FirebaseListAdapter.java:48)
at java.lang.reflect.Method.invoke(Native Method)
at android.arch.lifecycle.ClassesInfoCache$MethodReference.invokeCallback(ClassesInfoCache.java:215)
at android.arch.lifecycle.ClassesInfoCache$CallbackInfo.invokeMethodsForEvent(ClassesInfoCache.java:193) 
at android.arch.lifecycle.ClassesInfoCache$CallbackInfo.invokeCallbacks(ClassesInfoCache.java:184) 
at android.arch.lifecycle.ReflectiveGenericLifecycleObserver.onStateChanged(ReflectiveGenericLifecycleObserver.java:36) 
at android.arch.lifecycle.LifecycleRegistry$ObserverWithState.dispatchEvent(LifecycleRegistry.java:354) 
at android.arch.lifecycle.LifecycleRegistry.forwardPass(LifecycleRegistry.java:292) 
at android.arch.lifecycle.LifecycleRegistry.sync(LifecycleRegistry.java:332) 
at android.arch.lifecycle.LifecycleRegistry.moveToState(LifecycleRegistry.java:137) 
at android.arch.lifecycle.LifecycleRegistry.handleLifecycleEvent(LifecycleRegistry.java:123) 
at android.arch.lifecycle.ReportFragment.dispatch(ReportFragment.java:121) 
at android.arch.lifecycle.ReportFragment.onStart(ReportFragment.java:81) 
at android.app.Fragment.performStart(Fragment.java:2637) 
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1312) 
at android.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1549) 
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1611) 
at android.app.FragmentManagerImpl.dispatchMoveToState(FragmentManager.java:3039) 
at android.app.FragmentManagerImpl.dispatchStart(FragmentManager.java:2996) 
at android.app.FragmentController.dispatchStart(FragmentController.java:189) 
at android.app.Activity.performStart(Activity.java:7021) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2909) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3046) 
at android.app.ActivityThread.-wrap11(Unknown Source:0) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1688) 
at android.os.Handler.dispatchMessage(Handler.java:105) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6809) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767) 
03-08 10:22:40.020 20438-20438/com.iworld.daxi D/AppTracker: App Event: crash
I have also observed that the onDataChange() method is not getting triggered.

Android Studio & Firebase... Multiple activities

I have Firebase fully installed into Android Studio, and I've tested it with a couple 1 activity applications, but on the only application with more than one activity, it's not working.
When I try to do the following in my 'Sign up' code:
private void makeStudent(String email, String password) {
Student s = new Student(email, password);
Firebase ref = new Firebase("MYAPP.firebaseio.com/");
//took out my app name
Firebase studentlocation = ref.child("Student");
studentlocation.setValue(s); //this is the line on which I get the error
//also, when I go on my firebase site, it hasn't created the Student
//directory
}
The Firebase page said:
If your Android app has multiple activities, add this code to your Application Class. Otherwise add it in your main activity.
So, I looked around, and this is what I created:
I made a MyApplication.java file, which contained:
import com.firebase.client.Firebase;
public class MyApplication extends android.app.Application {
#Override
public void onCreate() {
super.onCreate();
Firebase.setAndroidContext(this);
}
}
Then I placed the following into AndroidManifest.xml:
android:name=".MyApplication"
Yet, I still receive an error on the exact same line.
How do I fix this Firebase issue? I appreciate any help I can get, please!
ERROR RECEIVED (scroll to the right in the code box):
FATAL EXCEPTION: main
Process: professionalgrader.professionalgrader, PID: 3827
com.firebase.client.FirebaseException: Failed to parse to snapshot
at com.firebase.client.Firebase.setValueInternal(Firebase.java:347)
at com.firebase.client.Firebase.setValue(Firebase.java:238)
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94)
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16)
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalArgumentException: length=0; index=0 (through reference chain: professionalgrader.professionalgrader.Student["listofTermClasses"])
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2615)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542)
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336)
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: com.fasterxml.jackson.databind.JsonMappingException: length=0; index=0 (through reference chain: professionalgrader.professionalgrader.Student["listofTermClasses"])
at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:184)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:605)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
at professionalgrader.professionalgrader.Student.getListofTermClasses(Student.java:252)
at java.lang.reflect.Method.invoke(Native Method)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.get(BeanPropertyWriter.java:679)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:534)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142) 
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118) 
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593) 
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
THE SECOND ERROR:
06-15 04:13:34.902 3089-3089/professionalgrader.professionalgrader E/AndroidRuntime: FATAL EXCEPTION: main
Process: professionalgrader.professionalgrader, PID: 3089
com.firebase.client.FirebaseException: Failed to parse to snapshot
at com.firebase.client.Firebase.setValueInternal(Firebase.java:347)
at com.firebase.client.Firebase.setValue(Firebase.java:238)
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94)
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16)
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalArgumentException: Attempt to invoke virtual method 'double professionalgrader.professionalgrader.Class.getGPA()' on a null object reference (through reference chain: professionalgrader.professionalgrader.Student["totalGPA"])
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2615)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542)
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336)
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Attempt to invoke virtual method 'double professionalgrader.professionalgrader.Class.getGPA()' on a null object reference (through reference chain: professionalgrader.professionalgrader.Student["totalGPA"])
at com.fasterxml.jackson.databind.ser.std.StdSerializer.wrapAndThrow(StdSerializer.java:184)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:605)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118)
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'double professionalgrader.professionalgrader.Class.getGPA()' on a null object reference
at professionalgrader.professionalgrader.Student.getTotalGPA(Student.java:199)
at java.lang.reflect.Method.invoke(Native Method)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.get(BeanPropertyWriter.java:679)
at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:534)
at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:597)
at com.fasterxml.jackson.databind.ser.BeanSerializer.serialize(BeanSerializer.java:142) 
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:118) 
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593) 
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:336) 
at com.firebase.client.Firebase.setValue(Firebase.java:238) 
at professionalgrader.professionalgrader.SignUp.makeStudent(SignUp.java:94) 
at professionalgrader.professionalgrader.SignUp.access$500(SignUp.java:16) 
at professionalgrader.professionalgrader.SignUp$1.onClick(SignUp.java:45) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Possible source of error because it told me it couldn't obtain the Snapshot at the line in makeStudent(), but makeStudent() doesn't use Snapshot. Only userExists() does. Note: The variable 'exists' is defined as a static boolean in the SignUp class.
private boolean userExists() {
Firebase ref = new Firebase("MYAPPNAME.firebaseio.com");
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
for (DataSnapshot postSnapShot: snapshot.getChildren()) {
Student s = postSnapShot.getValue(Student.class);
if(s.getEmail().equals(mEmailView.getText().toString())) {
exists = true;
}
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
exists = true;
}
});
return exists;
}
SOLUTION TO MY ISSUE:
I realized that Snapshot was never used in makeStudent(), and that was where the error started. Thus, I looked in the only place it was used... userExists(), and it turned out that I was correct! The error was produced by trying to identify Student s as a nonexistent student! Thus, I actually needed a try like such:
private boolean userExists() {
Firebase ref = new Firebase("MYAPPNAME.firebaseio.com");
ref.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot snapshot) {
Student s;
for (DataSnapshot postSnapShot: snapshot.getChildren()) {
try {
s = postSnapShot.getValue(Student.class);
if(s.getEmail().equals(mEmailView.getText().toString())) {
System.out.println(snapshot.getValue());
exists = true;
}
} catch(Exception e) {
exists = false;
}
}
}
#Override
public void onCancelled(FirebaseError firebaseError) {
exists = true;
}
});
return exists;
}

Firebase Android Trying to push child, and then a child below that

Confusing title, I know, but not quite shure how to explain.
Will do my best here.
What I am trying to accomplish is that when user clicks a button, the text from one field is pushed to firebase, then the text from the next field is pushed below that.
Something like this:
-"UID"--"Scripttitle"--"ScriptURL"
Here is the code that I am trying to do this with:
final EditText title = (EditText) rlLayout.findViewById(R.id.inputScriptTitle);
final EditText scripturl = (EditText) rlLayout.findViewById(R.id.inputScriptURL);
final Button button = (Button) rlLayout.findViewById(R.id.submitScriptButton);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
new Firebase("https://theatre-assistant.firebaseio.com/scripts")
.push()
.child("scripttitle")
.setValue(title.getText().toString());
new Firebase("https://theatre-assistant.firebaseio.com/scripts")
.push()
.child(title.getText().toString())
.setValue(scripturl);
I am shure I am just doing some really basic error, but as I am new to programming, I cant really see what that might be.
The error from logcat is:
--------- beginning of crash
04-28 12:26:15.860 4979-4979/com.langaard.theatreassistant E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.langaard.theatreassistant, PID: 4979
Theme: themes:{default=overlay:system, iconPack:system, fontPkg:system, com.android.systemui=overlay:system, com.android.systemui.navbar=overlay:system}
com.firebase.client.FirebaseException: Failed to parse to snapshot
at com.firebase.client.Firebase.setValueInternal(Firebase.java:357)
at com.firebase.client.Firebase.setValue(Firebase.java:248)
at com.langaard.theatreassistant.ManageScriptsFragment$1.onClick(ManageScriptsFragment.java:57)
at android.view.View.performClick(View.java:5204)
at android.view.View$PerformClick.run(View.java:21158)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5461)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalArgumentException: Conflicting getter definitions for property "importantForAccessibility": android.view.View#isImportantForAccessibility(0 params) vs android.view.View#getImportantForAccessibility(0 params)
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2615)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542)
at com.firebase.client.Firebase.setValueInternal(Firebase.java:346)
at com.firebase.client.Firebase.setValue(Firebase.java:248) 
at com.langaard.theatreassistant.ManageScriptsFragment$1.onClick(ManageScriptsFragment.java:57) 
at android.view.View.performClick(View.java:5204) 
at android.view.View$PerformClick.run(View.java:21158) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5461) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Conflicting getter definitions for property "importantForAccessibility": android.view.View#isImportantForAccessibility(0 params) vs android.view.View#getImportantForAccessibility(0 params)
at com.fasterxml.jackson.databind.SerializerProvider._createAndCacheUntypedSerializer(SerializerProvider.java:838)
at com.fasterxml.jackson.databind.SerializerProvider.findValueSerializer(SerializerProvider.java:387)
at com.fasterxml.jackson.databind.SerializerProvider.findTypedValueSerializer(SerializerProvider.java:478)
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:97)
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593)
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:346) 
at com.firebase.client.Firebase.setValue(Firebase.java:248) 
at com.langaard.theatreassistant.ManageScriptsFragment$1.onClick(ManageScriptsFragment.java:57) 
at android.view.View.performClick(View.java:5204) 
at android.view.View$PerformClick.run(View.java:21158) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5461) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.IllegalArgumentException: Conflicting getter definitions for property "importantForAccessibility": android.view.View#isImportantForAccessibility(0 params) vs android.view.View#getImportantForAccessibility(0 params)
at com.fasterxml.jackson.databind.introspect.POJOPropertyBuilder.getGetter(POJOPropertyBuilder.java:190)
at com.fasterxml.jackson.databind.introspect.POJOPropertyBuilder.getAccessor(POJOPropertyBuilder.java:283)
at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.removeIgnorableTypes(BeanSerializerFactory.java:678)
at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.findBeanProperties(BeanSerializerFactory.java:557)
at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.constructBeanSerializer(BeanSerializerFactory.java:373)
at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.findBeanSerializer(BeanSerializerFactory.java:268)
at com.fasterxml.jackson.databind.ser.BeanSerializerFactory._createSerializer2(BeanSerializerFactory.java:213)
at com.fasterxml.jackson.databind.ser.BeanSerializerFactory.createSerializer(BeanSerializerFactory.java:152)
at com.fasterxml.jackson.databind.SerializerProvider._createUntypedSerializer(SerializerProvider.java:873)
at com.fasterxml.jackson.databind.SerializerProvider._createAndCacheUntypedSerializer(SerializerProvider.java:833)
at com.fasterxml.jackson.databind.SerializerProvider.findValueSerializer(SerializerProvider.java:387) 
at com.fasterxml.jackson.databind.SerializerProvider.findTypedValueSerializer(SerializerProvider.java:478) 
at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:97) 
at com.fasterxml.jackson.databind.ObjectMapper._convert(ObjectMapper.java:2593) 
at com.fasterxml.jackson.databind.ObjectMapper.convertValue(ObjectMapper.java:2542) 
at com.firebase.client.Firebase.setValueInternal(Firebase.java:346) 
at com.firebase.client.Firebase.setValue(Firebase.java:248) 
at com.langaard.theatreassistant.ManageScriptsFragment$1.onClick(ManageScriptsFragment.java:57) 
at android.view.View.performClick(View.java:5204) 
at android.view.View$PerformClick.run(View.java:21158) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5461) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
You can't set view to setValue. scripturl is a EditText.
new Firebase("https://theatre-assistant.firebaseio.com/scripts")
.push()
.child(title.getText().toString())
.setValue(scripturl);
if you use like that you don't see any error.
new Firebase("https://theatre-assistant.firebaseio.com/scripts")
.child(title.getText().toString())
.push()
.setValue(scripturl.getText().toString);
Replace your following code
new Firebase("https://theatre-assistant.firebaseio.com/scripts")
.push()
.child(title.getText().toString())
.setValue(scripturl);
with
new Firebase("https://theatre-assistant.firebaseio.com/scripts")
.push()
.child(title.getText().toString())
.setValue(scripturl.getText().toString());
//because you pass directly object in value method replace and pass data from edit text not object

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