为什么在Android 4.4.2中{list}呈现时崩溃

Question

我正在使用一个在线测验考试系统，它将是一个Android应用程序。但是，当我尝试在listView中显示问题数据时，它在Android版本4.4.2中崩溃。但是在较高的android版本（例如8或9）中，它可以正常工作。 下面是我的所有代码：

activity_quiz_exam_.xml：

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#EEE4E4"

    tools:context=".Activity.Quiz_Exam_Activity">

        <LinearLayout
            android:background="#E9C6C6"
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

                <LinearLayout
                    android:layout_weight="1"
                    android:orientation="vertical"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content">
                        <TextView
                            android:id="@+id/topicNameTV"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:text=""
                            android:textSize="15sp"
                            android:layout_gravity="left"
                            android:padding="4dp"
                            android:textColor="#180056"
                            android:textStyle="bold"
                            />
                </LinearLayout>

                <LinearLayout
                    android:layout_weight="1.2"
                    android:orientation="vertical"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content">
                        <TextView
                            android:gravity="right"
                            android:id="@+id/remainingTimeTV"
                            android:layout_width="match_parent"
                            android:layout_height="wrap_content"
                            android:text="Total Time: 10:00 min"
                            android:textSize="15sp"
                            android:padding="4dp"
                            android:textColor="#180056"
                            android:textStyle="bold"
                            />
                </LinearLayout>

        </LinearLayout>

        <ProgressBar
            android:layout_gravity="center_horizontal"
            android:id="@+id/progressBar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:visibility="gone" />

        <ListView
            android:padding="2dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/listView"

            android:cacheColorHint="#f4f400"
            android:listSelector="#f95cd1"
            >

        </ListView>


</LinearLayout>

测验活动：

package com.example.sajib.smarticteducator.Activity;
import android.content.Intent;
import android.os.CountDownTimer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

import com.example.sajib.smarticteducator.Custom_Adapter_For_Quiz_Exam;
import com.example.sajib.smarticteducator.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import java.util.Random;


public class Quiz_Exam_Activity extends AppCompatActivity{
    // Button btn = new Button(this);
    public static String[] questionAns=new String[30];
    ProgressBar progressBar;
    ///////
    String[] Ques=new String[100];
    String[] Answer=new String[100];
    String[] OptionA=new String[100];
    String[] OptionB=new String[100];
    String[] OptionC=new String[100];
    String[] OptionD=new String[100];
    String Qname,join;

    TextView remainingTimeTV,topicNameTV;
    int[] a=new int[30];
    ListView listView;
    public static int size;
    int i,j,temp=0,ck=0,Max=1,Marks=0,k=0,count=0;
    DatabaseReference myRef1,myRef2,ref,ref2,userRef;
    String value,A,D,marks,max,username;
    String topicName;
    String topicType;
    int upperBound,lowerBound;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_quiz__exam_);
        this.setTitle("");

        Intent intent=getIntent();
        topicName = intent.getStringExtra("topicName");
         topicType = intent.getStringExtra("topicType");

        Toast.makeText(this,"Topic: "+topicName+".  Type: "+topicType,Toast.LENGTH_LONG).show();


        ref = FirebaseDatabase.getInstance().getReference("Quiz").child(topicName);
        userRef = FirebaseDatabase.getInstance().getReference("Users");

        listView=findViewById(R.id.listView);
        remainingTimeTV=findViewById(R.id.remainingTimeTV);
        topicNameTV=findViewById(R.id.topicNameTV);

        /// progressbar start
        progressBar=findViewById(R.id.progressBar);
        progressBar.setVisibility(View.VISIBLE);

        topicNameTV.setText(topicName);
        getMaxAndMarks(ref);


    }

    public void getMaxAndMarks(DatabaseReference ref){
        ref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                max=dataSnapshot.child("Max").getValue(String.class);
                marks=dataSnapshot.child("Marks").getValue(String.class);

                Marks=Integer.valueOf(marks);
                Max=Integer.valueOf(max);

                if(topicType.equals("Easy")){
                    lowerBound=1;
                    upperBound=Marks+5;
                }
                else if(topicType.equals("Medium")){
                    lowerBound=Marks;
                    upperBound=Max;
                }
                else if(topicType.equals("Hard")){
                    lowerBound=Marks+6;
                    upperBound=Max;
                }
                get_And_Display_AllData();
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }

    public void get_And_Display_AllData() {

        //  Toast.makeText(Quiz_Exam_Activity.this,"get_And_Display_AllData: Marks="+Marks,Toast.LENGTH_SHORT).show();

        ck=0;
        count=0;
        // Random number store
        Random random = new Random();
        for(i=0;i<Marks;i++)
        {
            temp = random.nextInt(upperBound - lowerBound+1) + lowerBound;
            for(j=0;j<i;j++)
            {
                if(temp==a[j])
                {
                    ck=1;
                    break;
                }
            }

            if(ck==1)
            {
                i--;
            }
            else
            {
                a[i]=temp;
                count=count+1;
            }
            ck=0;
        }
        k=0;
        getUserName();

    }


    public void getUserName()
    {
        DatabaseReference userRef = FirebaseDatabase.getInstance().getReference("Users")
                .child(FirebaseAuth.getInstance().getCurrentUser().getUid().toString());
        //  Toast.makeText(Quiz_Exam_Activity.this,"GetReference Function: ",Toast.LENGTH_LONG).show();
        userRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                username=dataSnapshot.child("name").getValue(String.class);
                getQuestionData();
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
        //  Toast.makeText(Quiz_Exam_Activity.this,"PK: "+pk,Toast.LENGTH_LONG).show();
    }

    public void getMessage(DatabaseReference ref){
        ref.addListenerForSingleValueEvent(new ValueEventListener() {

            public void onDataChange(DataSnapshot dataSnapshot) {
                Ques[k]=dataSnapshot.child("Question").getValue(String.class);
                Answer[k]=dataSnapshot.child("Ans").getValue(String.class);
                OptionA[k]=dataSnapshot.child("A").getValue(String.class);
                OptionB[k]=dataSnapshot.child("B").getValue(String.class);
                OptionC[k]=dataSnapshot.child("C").getValue(String.class);
                OptionD[k]=dataSnapshot.child("D").getValue(String.class);

                if (Ques[k] == null)
                {
                    get_And_Display_AllData();
                }
                else
                {
                    k++;
                    getQuestionData();
                }
            }
            public void onCancelled(DatabaseError error) {
                // TODO Auto-generated method stub

            }
        });

    }
    public void getQuestionData()
    {
        if(k<Marks)
        {
            //Qname=getQuestionName(a[k]);
            Qname="Q"+String.valueOf(a[k]);
            ref2 =ref.child(Qname);
           // join=join+" "+Qname;
            // Toast.makeText(Quiz_Exam_Activity.this,""+Qname,Toast.LENGTH_SHORT).show();
            //  testTV.setText(join);
            getMessage(ref2);
        }
        else
            callListViewAdapter();

    }

    public void callListViewAdapter()
    {
        String[] Ques=new String[Marks];
        String[] Answer=new String[Marks];
        String[] OptionA=new String[Marks];
        String[] OptionB=new String[Marks];
        String[] OptionC=new String[Marks];
        String[] OptionD=new String[Marks];

        for(i=0;i<Marks;i++)
        {
            Ques[i]=this.Ques[i];
            Answer[i]=this.Answer[i];
            OptionA[i]=this.OptionA[i];
            OptionB[i]=this.OptionB[i];
            OptionC[i]=this.OptionC[i];
            OptionD[i]=this.OptionD[i];
        }
        Custom_Adapter_For_Quiz_Exam adapter=new Custom_Adapter_For_Quiz_Exam(Quiz_Exam_Activity.this,Ques,OptionA,OptionB,OptionC,OptionD);

        LayoutInflater inflater=this.getLayoutInflater();
        LinearLayout listFooterView = (LinearLayout)inflater.inflate(
                R.layout.footer_button_of_listview, null);

        listView.addFooterView(listFooterView);
        progressBar.setVisibility(View.GONE);

        Button forward = listFooterView.findViewById(R.id.submitButton);
        forward.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                // Perform action on click
                SubmitAllAnswers();
            }
        });

        ///////////
        listView.setAdapter(adapter);
        countDownTimer();

    }

    public void countDownTimer(){
        new CountDownTimer(600000, 1000){

            @Override
            public void onTick(long millisUntilFinished) {
                long min,second;
                min=millisUntilFinished/(1000*60);
                second=millisUntilFinished%(1000*60);
                second=second/1000;
                remainingTimeTV.setText("Remaining Time: 0"+min+":"+second+" min");
            }

            @Override
            public void onFinish() {
                SubmitAllAnswers();
            }
        }.start();
    }
    public void SubmitAllAnswers( ) {

        String[] Answer=new String[Marks];
        String[] givenAnswer=new String[Marks];
        String[] OptionA=new String[Marks];
        String[] OptionB=new String[Marks];
        String[] OptionC=new String[Marks];
        String[] OptionD=new String[Marks];
        String[] Question=new String[Marks];
        String test ="";
        //   Toast.makeText(Quiz_Exam_Activity.this,"callListViewAdapter: K="+k,Toast.LENGTH_SHORT).show();

        for(i=0;i<Marks;i++)
        {
            if(questionAns[i]==null)
            {
                givenAnswer[i]="NA";
            }
            else
            {
                givenAnswer[i]=this.questionAns[i];
            }
            Answer[i]=this.Answer[i];
            OptionA[i]=this.OptionA[i];
            OptionB[i]=this.OptionB[i];
            OptionC[i]=this.OptionC[i];
            OptionD[i]=this.OptionD[i];
            OptionD[i]=this.OptionD[i];
            Question[i]=this.Ques[i];

        }

        Intent intent = new Intent(this, Accuracy_And_Solve_Sheet_Activity.class);
        intent.putExtra("question", Question);
        intent.putExtra("givenAnswer", givenAnswer);
        intent.putExtra("Answer", Answer);
        intent.putExtra("OptionA", OptionA);
        intent.putExtra("OptionB", OptionB);
        intent.putExtra("OptionC", OptionC);
        intent.putExtra("OptionD", OptionD);
        intent.putExtra("Marks", Marks);
        intent.putExtra("Username", username);
        finish();
        startActivity(intent);

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_items2,menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if(item.getItemId()== R.id.logout)
        {
            FirebaseAuth.getInstance().signOut();
            finish();
            Intent intent=new Intent(this,LoginActivity.class);
            startActivity(intent);
        }
        else if(item.getItemId()== R.id.feedback)
        {
            finish();
            Intent intent=new Intent(this,FeedbackActivity.class);
            startActivity(intent);
        }
        else if(item.getItemId()== R.id.publicPost)
        {
            finish();
            Intent intent=new Intent(this,NewsFeedActivity.class);
            startActivity(intent);
        }
        else if(item.getItemId()== R.id.timeline)
        {
            finish();
            Intent intent=new Intent(this,TimelineActivity.class);
            startActivity(intent);
        }
        else if(item.getItemId()== R.id.liveClass)
        {
            finish();
            Intent intent=new Intent(this,LiveClassActivity.class);
            startActivity(intent);

        }
        else if(item.getItemId()== R.id.home)
        {
            finish();
            Intent intent=new Intent(this,MainActivity.class);
            startActivity(intent);

        }

        return true;
    }

}

ListView布局设计：

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:layout_margin="3dp"
    android:background="#ffffff"
    android:orientation="vertical"
    android:padding="2dp"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:padding="5dp"
        android:id="@+id/questionTV"
        android:textSize="16sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1. Which is the Capital city of Bangladesh?"
        android:textColor="#180056"
        />
    <LinearLayout
        android:background="#EEE4E4"
        android:padding="5dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <RadioGroup
            android:paddingLeft="12dp"
            android:id="@+id/RG"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <RadioButton
                android:id="@+id/RB1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="Rangpur"
                android:textColorHint="#000000"
                android:textSize="15sp"
                />
            <RadioButton
                android:id="@+id/RB2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="Dhaka"
                android:textColorHint="#000000"
                android:textSize="15sp"
                />
            <RadioButton
                android:id="@+id/RB3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="Rajshahi"
                android:textColorHint="#000000"
                android:textSize="15sp"
                />
            <RadioButton
                android:id="@+id/RB4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:hint="Gobindagonj"
                android:textColorHint="#000000"
                android:textSize="15sp"
                />

        </RadioGroup>

    </LinearLayout>

</LinearLayout>

适配器：

package com.example.sajib.smarticteducator;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;

import static com.example.sajib.smarticteducator.Activity.Quiz_Exam_Activity.questionAns;

public class Custom_Adapter_For_Quiz_Exam extends BaseAdapter {
    String[] questions;
    String[] A;
    String[] B;
    String[] C;
    String[] D;
    Context context;
    LayoutInflater inflater;
    public Custom_Adapter_For_Quiz_Exam(Context context, String[] questions, String[] A, String[] B, String[] C, String[] D)
    {
        this.context=context;
        this.questions=questions;
        this.A=A;
        this.B=B;
        this.C=C;
        this.D=D;

    }
    @Override
    public int getCount() {
        return A.length;
    }

    @Override
    public Object getItem(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {

        if(convertView==null)
        {
            inflater= (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView=inflater.inflate(R.layout.quiz_exam_layout_design,null);
        }
        TextView questionTV=convertView.findViewById(R.id.questionTV);
        RadioGroup RG=convertView.findViewById(R.id.RG);
        RadioButton RB1=convertView.findViewById(R.id.RB1);
        RadioButton RB2=convertView.findViewById(R.id.RB2);
        RadioButton RB3=convertView.findViewById(R.id.RB3);
        RadioButton RB4=convertView.findViewById(R.id.RB4);

        String serial=String.valueOf(position+1);
        questionTV.setText(serial+". "+questions[position]);
        RB1.setText(A[position]);
        RB2.setText(B[position]);
        RB3.setText(C[position]);
        RB4.setText(D[position]);



        //////////////////////////

        RG.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                // TODO Auto-generated method stub
                int childCount = group.getChildCount();
                //  ViewParent parent = group.;
                for (int x = 0; x < childCount; x++) {
                    RadioButton btn = (RadioButton) group.getChildAt(x);

                    if (btn.getId() == checkedId) {
                        //   int getPosition = (Integer) group.getTag();//do this

                        questionAns[position]=btn.getText().toString();

                        // System.out.println(btn.getText().toString());
                        //  Toast.makeText(context,""+btn.getText().toString()+" Position: "+position,Toast.LENGTH_SHORT).show();


                    }

                }
            }
        });

        /////////////////////////

        return convertView;
    }

    @Override
    public int getViewTypeCount() {
        //Count=Size of ArrayList.
        return A.length;
    }

    @Override
    public int getItemViewType(int position) {

        return position;
    }

}