📱 App Overview:
This is a BMI (Body Mass Index) Calculator Android App that supports both Metric and Imperial units. It calculates BMI based on user input (age, gender, height, and weight), displays the result, categorizes it, and provides relevant health tips.

🔧 Key Functionalities:
1. Unit Switching (Metric ↔ Imperial):
Toggle between Metric (cm/kg) and Imperial (ft/in/lbs) using a SwitchMaterial.

UI fields update accordingly:

Metric: shows height in cm.

Imperial: shows feet and inches fields.

2. Input Validation:
Validates:

Age (between 2–120)

Weight:

Metric: 2–500 kg

Imperial: 5–1100 lbs

Height:

Metric: 50–300 cm

Imperial: 1–10 ft and 0–11 inches

Displays appropriate error messages if validation fails.

3. BMI Calculation:
Metric formula: BMI = weight (kg) / (height in meters)^2

Imperial formula: BMI = (weight (lbs) × 703) / (height in inches)^2

4. BMI Categories:
Based on BMI value:

< 16 → Severe Thinness

16–16.9 → Moderate Thinness

17–18.4 → Mild Thinness

18.5–24.9 → Normal

25–29.9 → Overweight

30–34.9 → Obese Class I

35–39.9 → Obese Class II

40+ → Obese Class III

5. Health Tips:
Each BMI category shows related health advice (e.g., "Eat more nutritious food", "Seek medical help", etc.).

6. Result Display:
Displays:

Calculated BMI

User's Age and Gender

BMI Category

Health Tip