xml file-
<EditText
android:id="@+id/radiusEditText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter radius" />
<Button
android:id="@+id/calculateButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/radiusEditText"
android:layout_marginTop="16dp"
android:text="Calculate" />
<TextView
android:id="@+id/resultTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/calculateButton"
android:layout_marginTop="16dp"
android:textSize="18sp"
android:text="The perimeter of the circle will be displayed here." />
java file-
package com.example.perimeterofcircle;
import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private EditText radiusEditText;
private Button calculateButton;
private TextView resultTextView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
radiusEditText = findViewById(R.id.radiusEditText);
calculateButton = findViewById(R.id.calculateButton);
resultTextView = findViewById(R.id.resultTextView);
calculateButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String radiusString = radiusEditText.getText().toString();
if (radiusString.isEmpty()) {
resultTextView.setText("Please enter the radius.");
return;
}
double radius = Double.parseDouble(radiusString);
double perimeter = 2 * Math.PI * radius;
resultTextView.setText("The perimeter of the circle is: " + perimeter);
}
});
}
}