Faild to settext in textview.Error:-android.content.res.Resources$NotFoundException: String resource ID #0x0

Question

First of all, I am a beginner at android. I am actually trying to build a quiz app. but I am getting stuck with an error that is unexpected.when I click Next button, I found an error. I was searching for the same question in StackOverflow but I could not find an expected solution. here is my code:-

MainActivity.java

package com.example.hellowandroid;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private Button falsebutton;
    private Button truebutton;
    private TextView questionTextView;
    private ImageButton nextButton;

    private int currentQuestionIndex = 0;

    private Question[] questionBank = new Question[]
            {       new Question(R.string.question_amendments, false), 
                    new Question(R.string.question_constitution, true),
                    new Question(R.string.question_declaration, true),
                    new Question(R.string.question_independence_rights, true),
                    new Question(R.string.question_religion, true),
                    new Question(R.string.question_government, false),
                    new Question(R.string.question_government_feds, false),
                    new Question(R.string.question_government_senators, true),
            };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);



        falsebutton = findViewById(R.id.false_button);
        truebutton = findViewById(R.id.true_button);
        questionTextView = findViewById(R.id.answer_text_view);
        nextButton = findViewById (R.id.next_button);


        falsebutton.setOnClickListener(this);
        truebutton.setOnClickListener(this);
        nextButton.setOnClickListener(this);



    }

    @Override
    public void onClick(View v) {

        switch (v.getId())

        {
            case R.id.false_button:
                Toast.makeText(MainActivity.this,"false",Toast.LENGTH_SHORT).show();
                break;
            case R.id.true_button:
                Toast.makeText(MainActivity.this,"true",Toast.LENGTH_SHORT).show();
                break;

            case R.id.next_button:

                //go to next question
                currentQuestionIndex = (currentQuestionIndex + 1) % questionBank.length; 

                Log.d("Current Index","onClick"+currentQuestionIndex);




             
                questionTextView.setText((questionBank[currentQuestionIndex].getAnswerResId()));


        }

    }
}

maybe this line questionTextView.setText((questionBank[currentQuestionIndex].getAnswerResId())); has a problem, I am not sure.

Question.java

package com.example.hellowandroid;

public class Question {
    private int answerResId;
    private boolean answerTrue;

    public Question (int answerResId,boolean answerTrue)
    {
        answerResId=this.answerResId;
        answerTrue=this.answerTrue;

    }

    public int getAnswerResId() {
        return answerResId;
    }

    public void setAnswerResId(int answerResId) {
        this.answerResId = answerResId;
    }

    public boolean isAnswerTrue() {
        return answerTrue;
    }

    public void setAnswerTrue(boolean answerTrue) {
        this.answerTrue = answerTrue;
    }
}

activity_main.xml

<?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"
    android:orientation="vertical"
    android:gravity="center"
    android:background="@color/design_default_color_primary_dark"
    tools:context=".MainActivity">

    <ImageView
        android:src="@android:drawable/ic_dialog_dialer"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <TextView
        android:id="@+id/answer_text_view"
        android:text="@string/question_declaration"
        android:padding="10dp"
        android:textColor="@android:color/background_light"
        android:textSize="16sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>



    <LinearLayout
        android:orientation="horizontal"
        android:layout_marginTop="64dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

        <Button
            android:id="@+id/true_button"
            android:text="@string/true_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

        <Button
            android:id="@+id/false_button"
            android:text="@string/false_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>




    </LinearLayout>

    <ImageButton
        android:contentDescription="@string/next_text"
        android:id="@+id/next_button"
        android:src="@android:drawable/ic_media_next"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>



    
</LinearLayout>

strings.xml

<resources>
    <string name="app_name">HellowAndroid</string>

    <string name="true_text">true</string>
    <string name="false_text">false</string>
    <string name="question_declaration">General Knowledge Of US Students.</string>
    <string name="correct_answer">That\'s correct</string>
    <string name="wrong_answer">That\'s incorrect</string>
    <string name="question_constitution">The Supreme law of the land is the Constitution.</string>
    <string name="question_amendments">The (U.S.) Constitution has 26 Amendments.</string>
    <string name="question_independence_rights">The two rights in the Declaration of Independence are:
        \n \t <b>life</b> \n  \t <b>pursuit of happiness</b>.</string>
    <string name="question_religion">Freedom of religion means:
        \n \t <b>You can practice any religion, or not practice a religion</b>.</string>
    <string name="question_government">Journalists is one branch or part of the government.</string>
    <string name="question_government_feds">Congress does not make federal laws.</string>
    <string name="question_government_senators">There are one hundred (100) U.S. Senators.</string>
    <string name="next_text">next</string>

</resources>

Here is the error:-

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.hellowandroid, PID: 27079
    android.content.res.Resources$NotFoundException: String resource ID #0x0
        at android.content.res.Resources.getText(Resources.java:1184)
        at android.widget.TextView.setText(TextView.java:5218)
        at com.example.hellowandroid.MainActivity.onClick(MainActivity.java:81)
        at android.view.View.performClick(View.java:6312)
        at android.view.View$PerformClick.run(View.java:23985)
        at android.os.Handler.handleCallback(Handler.java:751)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6816)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1563)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1451)

also i tried questionTextView.setText(""+ questionBank[currentQuestionIndex]. getAnswerResId()); but same error. it's main is mainly happend when i click next button.how i resolve this issue.

Answer 1

You have set these variables the wrong way.

public Question (int answerResId, boolean answerTrue)
{
  answerResId = this.answerResId;
  answerTrue = this.answerTrue;
}

It should have been like this:

public Question (int answerResId, boolean answerTrue)
{
  this.answerResId = answerResId;
  this.answerTrue = answerTrue;
}

Answer 2

The value of currentQuestionIndex must be smaller than the value of questionBank.size() :

if (currentQuestionIndex >= questionBank.size()) {
   throw new IndexOutOfBoundsException(
       "no item exists at index " + currentQuestionIndex
   );
}

And I really do not understand the purpose of this % modulo operation here:

currentQuestionIndex = (currentQuestionIndex + 1) % questionBank.length; 

The common way of writing that might rather be:

currentQuestionIndex ++;