Android program crashes

Question

Thanks for the help everyone. All problems sorted!

Try searching the question before posting. This is a duplicate. — JoxTraex, Nov 14 '13 at 02:56

score 3 · Accepted Answer · answered Nov 14 '13 at 00:39

3

never ever ever use == to check equality for strings in Java. you must always use

string1.equals(string2)

the line

if (currentString == "+")

will always return false, so you must use

if (currentString.equals("+"))

answered Nov 14 '13 at 00:39

panini

2,026
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the same goes for all other places where you aren't using .equals() when checking strings. – panini Nov 14 '13 at 00:40

score 0 · Answer 2 · answered Nov 14 '13 at 00:40

0

The problem is that you do Integer.toString(c) before you check to see if c is numeric.

Also, be aware that you shouldn't compare strings with == you must use .equals(), or you will get unexpected results.

answered Nov 14 '13 at 00:40

GreyBeardedGeek

27,958
2
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c is an int to start with (its the for loop counter), so that shouldn't be an issue. – panini Nov 14 '13 at 00:42

score 0 · Answer 3 · answered Nov 14 '13 at 00:43

I think the problem is that your IF returns "false" in this fragment:

    //Check if the element is a sign
    if(currentElement == "+" || currentElement == "-" || currentElement == "*" || currentElement == "/")
    {
        Log.i("INFORMATION", "Sign found!");
        currentSign = currentElement; //Save into temporary storage to be used next loop
    }
    else // Element is a number
    {
        currentNumber = Double.parseDouble( currentElement ); //Convert number to integer
    }

So you get fatal error when you try to execute Double.parseDouble(currentElement) with currentElement="+".

I would use string comparison instead of "==", like this:

if("+".equals(currentElement) || "-".equals(currentElement) ... etc

Android program crashes

3 Answers3