Validation: Added Toast messages for empty or invalid input

app/src/main/java/com/example/assignmentone/MainActivity.java

@@ -6,6 +6,7 @@ import android.view.View;
 import android.widget.Button;
 import android.widget.RadioButton;
 import android.widget.TextView;
+import android.widget.Toast;
 
 import androidx.activity.EdgeToEdge;
 import androidx.appcompat.app.AppCompatActivity;
@@ -43,6 +44,7 @@ public class MainActivity extends AppCompatActivity {
                 String userInput = tempInput.getEditText().getText().toString().trim();
                 if(userInput.isEmpty()) {
                     tempInput.setError("Please enter a temperature");
+                    Toast.makeText(MainActivity.this, "Error: No value entered", Toast.LENGTH_SHORT).show();
                     return;
                 }
                 try {
@@ -61,6 +63,7 @@ public class MainActivity extends AppCompatActivity {
 
                 } catch (NumberFormatException e) {
                     tempInput.setError("Invalid number format");
+                    Toast.makeText(MainActivity.this, "Error: Invalid number or special characters", Toast.LENGTH_SHORT).show();
                 }
             }
         });