Add All Country translations and Functional Calculator

app/src/main/java/com/exuberant/calci/HomeActivity.java

@@ -1,23 +1,29 @@
 package com.exuberant.calci;
 
 import androidx.appcompat.app.AppCompatActivity;
-
 import android.os.Bundle;
 import android.view.View;
 import android.widget.TextView;
-import android.widget.Toast;
-
 import com.google.android.material.button.MaterialButton;
 
 public class HomeActivity extends AppCompatActivity implements View.OnClickListener {
 
     private String currentNumber = "", totalCalculation = "";
+    private char operator ;
+    private double firstOperand;
+    private double secondOperand;
     private TextView totalCalculationTextView, currentAnswerTextView;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_home);
+
+        initializeViews();
+
+    }
+
+    private void initializeViews() {
         findViewById(R.id.btn_zero).setOnClickListener(this);
         findViewById(R.id.btn_one).setOnClickListener(this);
         findViewById(R.id.btn_two).setOnClickListener(this);
@@ -62,8 +68,11 @@ public void onClick(View view) {
 
             //Handle calculation
             case R.id.btn_equals:
+                firstOperand = Double.valueOf(totalCalculation.substring(0,totalCalculation.length()-1));
+                secondOperand = Double.valueOf(currentNumber);
+                operator = totalCalculation.charAt(totalCalculation.length()-1);
                 totalCalculation += currentNumber;
-                calculateAnswer();
+                calculateAnswer(firstOperand, secondOperand, operator);
                 break;
 
             //Handle other numerical button clicks
@@ -93,20 +102,37 @@ private double add(double a, double b){
     }
 
     private double sub(double a, double b){
-        return  a + b;
+        return  a - b;
     }
 
     private double mul(double a, double b){
-        return  a + b;
+        return  a * b;
     }
 
     private double div(double a, double b){
-        return a + b;
+        return a / b;
     }
 
-    private void calculateAnswer(){
+    private void calculateAnswer(Double firstOperand, Double secondOperand, char operator){
         //Use totalCalculation string to get final answer and display it
         double answer = 0.0;
+        if(operator == '+')
+        {
+            answer = add(firstOperand, secondOperand);
+        }
+        else if(operator == '-')
+        {
+            answer = sub(firstOperand, secondOperand);
+        }
+        else if (operator == '/')
+        {
+            answer = div(firstOperand, secondOperand);
+        }
+        else
+        {
+            answer = mul(firstOperand, secondOperand);
+        }
+        currentNumber = String.valueOf(answer);
         updateDisplay();
     }
-}
+}

app/src/main/res/layout/content_answer_view.xml

@@ -11,7 +11,7 @@
         android:layout_marginTop="16dp"
         android:gravity="end"
         android:textSize="24sp"
-        android:text="Total Calculation"
+        android:text="@string/total_calculation"
         android:textColor="#757575"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"/>
@@ -24,7 +24,7 @@
         android:layout_marginEnd="16dp"
         android:gravity="end"
         android:textSize="32sp"
-        android:text="Current Calculation"
+        android:text="@string/current_calculation"
         android:textColor="#757575"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"/>