pici

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
EditText e1;
TextView t1;
Button b1,b2;
@SuppressLint("MissingInflatedId")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
e1=findViewById(R.id.eradius);
t1=findViewById(R.id.tandisplay);
b1=findViewById(R.id.btnperi);
b2=findViewById(R.id.btnarea);

    b1.setOnClickListener(new View.OnClickListener() {
        @SuppressLint("SetTextI18n")
        @Override
        public void onClick(View view) {
            double num=Double.parseDouble(e1.getText().toString());
            double pi=3.14;
            double peri=2*pi*num;
            t1.setText("Perimeter of circle"+peri);
        }
    });
    b2.setOnClickListener(new View.OnClickListener() {
        @SuppressLint("SetTextI18n")
        @Override
        public void onClick(View view) {
            double num=Double.parseDouble(e1.getText().toString());
            double pi=3.14;
            double area=pi*num*num;
            t1.setText("Area of circle"+area);
        }
    });

}

}

<?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="wrap_content" android:orientation="vertical" tools:context=".MainActivity">

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

    <TextView
        android:id="@+id/tradius"
        android:layout_width="211dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="@string/radius"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/eradius"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:ems="10"
        android:hint="@string/Enter_radius"
        android:inputType="textPersonName"
        android:autofillHints="" />

</LinearLayout>

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

    <TextView
        android:id="@+id/tdisplay"
        android:layout_width="2dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="@string/answer"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/tandisplay"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <Button
        android:id="@+id/btnperi"
        android:layout_width="104dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="@string/Perimeter"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        tools:ignore="HardcodedText"
        style="?android:attr/buttonBarButtonStyle" />

    <Button
        android:id="@+id/btnarea"
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="@string/Area"
        android:textAppearance="@style/TextAppearance.AppCompat.Large" />
</LinearLayout>

</LinearLayout>