CODEWITHSUNDEEP
javaandroid
63alfred
63alfred

Reputation: 37

Proper use of for and if statements in Java/Android

I have an two arrays, one is cityUSA[i] and one is decimalUSA[i]. Each has over 1500 entries, cityUSA[100] goes with decimalUSA[100] and so on. I find the city people are in via location services in Android and then I compare it to the list of cities I have in the cityUSA[i] array. I then search for a match and use the i of the match to find the related value of decimalUSA[i] in that array. Here is the code:

loc.getLatitude(); loc.getLongitude(); Geocoder geocoder = new Geocoder(rate.this, Locale.ENGLISH);

        try {
              List<Address> addresses = geocoder.getFromLocation(loc.getLatitude(), loc.getLongitude(), 1);

              TextView rateText = (TextView)findViewById(R.id.taxRate);
              TextView locationText = (TextView)findViewById(R.id.taxLocation);

              if(addresses != null) {
               Address returnedAddress = addresses.get(0);
               String city = returnedAddress.getLocality();
               locationText.setText(city);

                int i;
                for (i = 0; i  <= cityUSA.length; i++){
                    if (cityUSA[i] == city) {
                    String PrecentString = decimalRate[i];
                    rateText.setText(PrecentString);
                    break;
                    }
                }


              }
              else{
                  locationText.setText("No City returned!");
                  rateText.setText("No Rate returned!");
              }


             } 


              catch (IOException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
              TextView locationText = (TextView)findViewById(R.id.Rate);
              locationText.setText("Cannot get Location!");
             }

The application bombs out when I try to run it. If I remove the for statment:

                int i;
                for (i = 0; i  <= cityUSA.length; i++){
                    if (cityUSA[i] == city) {
                    String PrecentString = decimalRate[i];
                    rateText.setText(PrecentString);
                    break;
                    }
                }

It does not bomb out, but then again it does not perform the search either.

Any suggestions?

Upvotes: 0

Views: 170

Answers (3)

eggyal
eggyal

Reputation: 125925

Firstly, comparing two string objects using == checks whether they are the same object, not whether they contain the same string. You should compare strings with .equals().

Secondly, your array index will go out of bounds if the match fails (which, because of the above, it probably will). Valid indices in cityUSA are 1 to cityUSA.length-1, whereas the for loop will continue to cityUSA.length.

Thirdly, having two codependent arrays in this way is not great design: it ought to be possible to find an Object-oriented pattern suitable to your needs.

Upvotes: 0

Chris Shaffer
Chris Shaffer

Reputation: 32575

You are iterating one too many times (of course, this will only happen if the city doesn't exist in the array); Should be for (i = 0; i < cityUSA.length; i++){.

As to why you may not find the city in the array, you may have a case-sensitivity issue. Maybe try if (cityUSA[i].equalsIgnoreCase(city)){ instead.

Upvotes: 0

Vinay
Vinay

Reputation: 6342

Unless you aren't, I see one immediate error in that you're comparing two strings with the "==" operator:

if(cityUSA[i]==city)

Instead, to check the contents of each string (and whether they are equal):

if(cityUSA[i].equals(city))

Also, the <= in the for loop will cause an off by one error. Keep it just as a "<".

Also, what do you mean by "bomb out"? It would be helpful if you gave a specific exception being thrown and on what line.

Upvotes: 1

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