From 3297fd0c471542cec3016df31236d078006f20ec Mon Sep 17 00:00:00 2001
From: sivan <sivan.sundar@gmail.com>
Date: Mon, 7 Oct 2019 18:47:01 +0530
Subject: [PATCH] Fixed issue #6 - Crash on pressing operator buttons.

---
 .../java/com/exuberant/calci/HomeActivity.java     | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/app/src/main/java/com/exuberant/calci/HomeActivity.java b/app/src/main/java/com/exuberant/calci/HomeActivity.java
index 82471e3..55ae2d8 100644
--- a/app/src/main/java/com/exuberant/calci/HomeActivity.java
+++ b/app/src/main/java/com/exuberant/calci/HomeActivity.java
@@ -3,6 +3,7 @@
 import androidx.appcompat.app.AppCompatActivity;
 
 import android.os.Bundle;
+import android.util.Log;
 import android.view.View;
 import android.widget.TextView;
 import android.widget.Toast;
@@ -11,7 +12,9 @@
 
 public class HomeActivity extends AppCompatActivity implements View.OnClickListener {
 
+    private static final String TAG = "HomeActivity";
     private String currentNumber = "", totalCalculation = "";
+
     private TextView totalCalculationTextView, currentAnswerTextView;
 
     @Override
@@ -66,6 +69,7 @@ public void onClick(View view) {
                 calculateAnswer();
                 break;
 
+
             //Handle other numerical button clicks
             default:
                 currentNumber += button.getText().toString();
@@ -83,8 +87,12 @@ private void handleOperatorClick(String operator){
             totalCalculation += currentNumber + operator;
             currentNumber = "";
         } else {
-            totalCalculation = totalCalculation.substring(0, totalCalculation.length() - 1);
-            totalCalculation += operator;
+            if (!totalCalculation.isEmpty()) {
+
+                totalCalculation = totalCalculation.substring(0, totalCalculation.length() - 1);
+                totalCalculation += operator;
+
+            }
         }
     }
 
@@ -107,6 +115,8 @@ private double div(double a, double b){
     private void calculateAnswer(){
         //Use totalCalculation string to get final answer and display it
         double answer = 0.0;
+        currentNumber = "";
+        Log.d(TAG, "calculateAnswer: totalCalculationString : " + totalCalculation);
         updateDisplay();
     }
 }