PROGRAM 7:
XML CODE:
<?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"
 tools:context=".MainActivity">
 <TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/qt"
 android:text="question will appear here"
 android:textSize="18sp"
 android:layout_alignParentTop="true"
 android:layout_centerHorizontal="true"/>
 <RadioGroup
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/ag"
 android:layout_below="@id/qt"
 android:layout_marginTop="16dp">
 <RadioButton
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/o1"
 android:text="Option 1"/>
 <RadioButton
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/o2"
 android:text="Option 2"/>
 <RadioButton
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/o3"
 android:text="Option 3"/>
 <RadioButton
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/o4"
 android:text="Option 4"/>
 </RadioGroup>
 <Button
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/sb"
 android:text="submit answer"
 android:layout_below="@id/ag"
 android:layout_marginTop="16dp"
 android:layout_centerHorizontal="true"/>
 <TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:id="@+id/res_t"
 android:text="results will appear here"
 android:textSize="18sp"/>
</LinearLayout>
JAVA CODE:
package com.example.myapplication;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 questiontextview = findViewById(R.id.qt);
 scoretextview = findViewById(R.id.res_t);
 answergroup = findViewById(R.id.ag);
 submitButton = findViewById(R.id.sb);
 loadQuestion();
 submitButton.setOnClickListener(v -> {
 int selectedanswer = answergroup.getCheckedRadioButtonId();
 if(selectedanswer != -1) {
 int selectedindex = (selectedanswer == R.id.o1) ? 0 :
(selectedanswer == R.id.o2) ? 1 : (selectedanswer == R.id.o3) ? 2 : 3;
 if (selectedindex == correctAnswer[currentindex]) score++;
 if (++currentindex < questions.length) loadQuestion();
 else {
 questiontextview.setText("quiz completed");
 scoretextview.setText("final score:" + score);
 submitButton.setEnabled(false);
 }
 }
 });
 }
 private void loadQuestion(){
 questiontextview.setText(questions[currentindex]);
 for(int i=0;i<4;i++){

((RadioButton)answergroup.getChildAt(i)).setText(options[currentindex][
i]);
 }
 answergroup.clearCheck();
 scoretextview.setText("score:"+score);
 }
 private TextView questiontextview,scoretextview;
 private RadioGroup answergroup;
 private Button submitButton;
 private int currentindex=0,score=0;
 private String[]questions={
 "what is the capital of france?","which planet is known as the red
planet?","what is the largest ocean on the earth "
 };
 private String[][]options={
 {"paris","london","berlin","madrid"},
 {"earth","mars","jupiter","saturn"},
 {"atlantics","indian","arctic","pacific"}
 };
private int[]correctAnswer={0,1,3};
}