IllegalStateException and NullPointer Exception

Question

I am trying to run the following activity but as soon as I click on submit button , my app crashes with the given exception.

I have already separated the declaration and initialisation.

My Complaint.java file is as follows

package com.example.android.complaintbox_ritesltd;

import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;



public class Complaint extends AppCompatActivity {

    private FirebaseDatabase mFirebaseDatabase;
    private DatabaseReference mComplaintsDatabaseRegerence;
    private EditText ct;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        mFirebaseDatabase=FirebaseDatabase.getInstance();
        mComplaintsDatabaseRegerence=mFirebaseDatabase.getReference().child("Complaints");
        ct=findViewById(R.id.comp_box);



        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_complaint);

    }
    public void submitButton(View view) {
        //TODO: Send Complaint to the database
       ComplaintDetails complaintDetails=new ComplaintDetails(ct.getText().toString());
       mComplaintsDatabaseRegerence.push().setValue(complaintDetails);


        //Clears the input box
        ct.setText("");
    }

}

and activity_complaint.xml is as follows

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Complaint"
    android:orientation="vertical"
    android:background="#E3F2FD"

    >



    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textColor="@color/colorPrimary"
        android:text="Write Your Complaint Here!"
        android:textSize="30dp"
        android:padding="20dp"
        android:layout_marginTop="30dp"
        android:textStyle="bold"

        />

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="30dp"
        android:hint="Complaint!"
        android:id="@+id/comp_box"
        android:layout_marginTop="60dp"
        android:inputType="text"
        android:background="@drawable/white_round_corner_box"
        android:layout_margin="14dp"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Submit"
        android:layout_margin="14dp"
        android:padding="14dp"
        android:textAllCaps="true"
        android:background="@drawable/rounded_corners"
        android:textColor="@android:color/white"
        android:layout_marginTop="90dp"
        android:id="@+id/submit_button"
        android:onClick="submitButton"
        />

</LinearLayout>

The errors are:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.android.complaintbox_ritesltd, PID: 3227
    java.lang.IllegalStateException: Could not execute method for android:onClick
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:390)
        at android.view.View.performClick(View.java:6597)
        at android.view.View.performClickInternal(View.java:6574)
        at android.view.View.access$3100(View.java:778)
        at android.view.View$PerformClick.run(View.java:25885)
        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:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.reflect.InvocationTargetException
        at java.lang.reflect.Method.invoke(Native Method)
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385)
        at android.view.View.performClick(View.java:6597) 
        at android.view.View.performClickInternal(View.java:6574) 
        at android.view.View.access$3100(View.java:778) 
        at android.view.View$PerformClick.run(View.java:25885) 
        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:6669) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
        at com.example.android.complaintbox_ritesltd.Complaint.submitButton(Complaint.java:42)
        at java.lang.reflect.Method.invoke(Native Method) 
        at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:385) 
        at android.view.View.performClick(View.java:6597) 
        at android.view.View.performClickInternal(View.java:6574) 
        at android.view.View.access$3100(View.java:778) 
        at android.view.View$PerformClick.run(View.java:25885) 
        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:6669) 
        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:858)

Welcome to StackOverflow. When writing a question, please use the preview pane to verify your post is formatted as you expect. I fixed it for you this time. — Jim Garrison, Jun 21 '19 at 15:17
Clearly, `ct=findViewById(R.id.comp_box);` returns `null` so at `ComplaintDetails complaintDetails=new ComplaintDetails(ct.getText().toString());` you get NPE. — Jim Garrison, Jun 21 '19 at 15:31
Possible duplicate of [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Jim Garrison, Jun 21 '19 at 15:32

Ashish · Accepted Answer · 2019-06-21T16:00:14.037

public class Complaint extends AppCompatActivity {

    private FirebaseDatabase mFirebaseDatabase;
    private DatabaseReference mComplaintsDatabaseRegerence;
    private EditText ct;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_complaint);
        mFirebaseDatabase=FirebaseDatabase.getInstance();
        mComplaintsDatabaseRegerence=mFirebaseDatabase.getReference().child("Complaints");
        ct=findViewById(R.id.comp_box); // It needs to be below your setContentView.
    }
}

Reason :

Cause onCreate needs to know what is your layout you using for Your Class.

then you can assign the your Edittext or it leads to crash with nullpointer Exception.

Thank you @Ashish! you really saved my time :) – Yashi Gupta Jun 21 '19 at 15:51 — Yashi Gupta, Jun 21 '19 at 15:51

IllegalStateException and NullPointer Exception

1 Answers1