A scientific calculator app for Android with three functional tabs: Math, PID, and Electric.
Build: 2.0-20260413 | Author: hjltu | minSdk: 24 | targetSdk: 34
Full-featured scientific calculator with expression parsing, history, and percentage support.
Operations:
- Basic:
+,-,*,/ - Power:
^ - Percentage:
%(e.g.,8%2 = 0.16— left * right / 100) - Parentheses:
(,) - Scientific:
sin,cos,tan,sqrt(arguments in degrees) - Decimal:
.
Controls:
C— clear expression⌫— backspace=— evaluate
History: Previous calculations appear in the history list above the buttons.
Display: Long expressions expand over the history area without shifting buttons.
Ziegler-Nichols PID tuning calculator.
Input:
- Ku — Ultimate gain
- Tu — Ultimate period
Output (PID formulas):
- Kp = 0.6 * Ku
- Ki = 1.2 * Ku / Tu
- Kd = 0.075 * Ku * Tu
Ohm's law and power calculator.
Input: Any 2 of 4 values:
- U — Voltage (V)
- R — Resistance (Ω)
- I — Current (A)
- P — Power (W)
Formulas used:
- U = I * R
- P = U * I
- P = I² * R
- P = U² / R
Press Calculate to compute the remaining 2 values.
app/src/main/
├── java/com/example/calculator/
│ ├── MainActivity.java — Tab host (Math / PID / Electric)
│ ├── MathCalcFragment.java — Math calculator logic
│ ├── PidCalcFragment.java — Ziegler-Nichols PID calculator
│ ├── ElectricCalcFragment.java — Ohm's law electric calculator
│ └── ExpressionEvaluator.java — Recursive-descent math parser
├── res/
│ ├── layout/
│ │ ├── activity_main.xml — TabLayout + FrameLayout
│ │ ├── fragment_math_calc.xml — Calculator grid + display
│ │ ├── fragment_pid_calc.xml — PID input/output form
│ │ └── fragment_electric_calc.xml — Electric input/output form
│ └── values/
│ └── strings.xml
└── AndroidManifest.xml
- AndroidX AppCompat 1.6.1
- Material Components 1.11.0
- ConstraintLayout 2.1.4
- GridLayout 1.0.0
./gradlew assembleDebug
APK output: app/build/outputs/apk/debug/app-debug.apk