5 input based search form for Android

Question

I've been trying to look for a better way in which a user has up to 5 inputs in which they can search for results in a database.

I have 2 EditTexts in which the user can have alphanumeric values and 3 Spinners. As you can see in the code, it's badly designed in the way it consists of if or else if statements which is just horrible, but it works.

What would be the best way to avoid long if or else if statements and be able to pick and choose what you would like to search for in the database? I know there is the switch but does that not just take a value and return the result of something on the one case?

if(tag != "" && name != "" && breed != "Breed" && sex != "Sex"){
 cursor = cupboard().withDatabase(sqLiteDatabase).query(Cattle.class)
 .withSelection("tag LIKE ? AND name LIKE ? AND breed LIKE ? AND sex LIKE ?", tag, name, breed, sex)
 .getCursor();
 if(cursor.getCount() < 1){
 Toast.makeText(getContext(), "Sorry, No Cattle with those details!", Toast.LENGTH_LONG).show();
 }
} else if (tag == "" && name == "" && breed == "Breed"){
 cursor = cupboard().withDatabase(sqLiteDatabase).query(Cattle.class)
 .withSelection("sex LIKE ?", sex)
 .getCursor();
 if(cursor.getCount() < 1){
 Toast.makeText(getContext(), "Sorry, No Cattle with those details!", Toast.LENGTH_LONG).show();
 }
} else if (breed != "Breed"){
 cursor = cupboard().withDatabase(sqLiteDatabase).query(Cattle.class)
 .withSelection("breed LIKE ?", breed)
 .getCursor();
 if(cursor.getCount() < 1){
 Toast.makeText(getContext(), "Sorry, No Cattle with those details!", Toast.LENGTH_LONG).show();
 }
} else if (sex != "Sex"){
 cursor = cupboard().withDatabase(sqLiteDatabase).query(Cattle.class)
 .withSelection("sex LIKE ?", sex)
 .getCursor();
 if(cursor.getCount() < 1){
 Toast.makeText(getContext(), "Sorry, No Cattle with those details!", Toast.LENGTH_LONG).show();
 }
} else if (tag == "" && name == "" && sex == "Sex"){
 cursor = cupboard().withDatabase(sqLiteDatabase).query(Cattle.class)
 .withSelection("breed LIKE ?", breed)
 .getCursor();
 if(cursor.getCount() < 1){
 Toast.makeText(getContext(), "Sorry, No Cattle with those details!", Toast.LENGTH_LONG).show();
 }
}

Answer 1

Disclaimer: I'm a C# developer and I haven't written Java in ages.

First of all I'd move this to a separate method, with (String selection, String[] selectionArgs) as parameters:

cursor = cupboard().withDatabase(sqLiteDatabase).query(Cattle.class)
 .withSelection(selection, selectionArgs)
 .getCursor();
if(cursor.getCount() < 1){
 Toast.makeText(getContext(), "Sorry, No Cattle with those details!", Toast.LENGTH_LONG).show();

You can now call that method in each if instead of copy-pasting the same code over and over again and only changing a small part.

---

But I'm mostly baffled by the convoluted logic WRT those ifs and the resulting selection and selectionArgs. Are you sure you didn't mean to construct something like this (pseudo-code):

var selectionOptions = new Dictionary<String, String>();
if(breed != "" && breed != "Breed")
{
 selectionOptions.Add("breed LIKE ?", breed);
}
if(sex != "" && sex != "Sex")
{
 selectionOptions.Add("sex LIKE ?", sex);
}
// same for tag and name 
// now construct the selection
var selection = string.Join(" AND ", selectionOptions.Keys);
// pass the selection and its arguments to the method I mentioned above
ThatMethodMentionedAbove(selection, selectionOptions.Values);

The logic being:

• Look at each of the four possible parameters
• Only add a parameter to the query if it has a value and its value is not its own name

That would make sense to me, whereas this kind of logic:

if (tag == "" && name == "" && breed == "Breed"){
 // snip
 .withSelection("sex LIKE ?", sex)

... just looks... odd. And indeed, very un-maintainable.

• SmiffyKmc: Thanks for the help! Even looking at your code has thought me something. Yeah it's complicated the way I wrote it alright and I fell into just coping and pasting the next statement to force it to work almost. The last code example you posted for the tag, name, breed should have been commented. Breed is a Spinner which the default value is Breed. I thought the logic of having the Spinner equal to Breed would show they are all default except the sex value.
• Vogel612: small note: what you're advertising as Dictionary is named Map in java. of course you also know there's no var and that string.Join is not there in Java. Additional note: Maps don't guarantee traversal order as you want it here. Most maps do it right, but it's not guaranteed :/ (not that Dictionary would guarantee it either)
• BCdotWEB: @Vogel612 Yeah, I know it isn't robust code, it's more about the idea, the logic: compile a list of key-value pairs and loop through that list to construct the query.
• SmiffyKmc: Yeah even the logic sounds better then the way I tried to do it xD. It's after clicking in my head on how you came across it in C# and how to implement it in my code! I actually really appreciate the help everyone as this is my first job which the app is demoing to a client and I was asked to do it and I don't want to write lazy code :)
• SmiffyKmc: @BCdotWEB thanks for helping me out. Thanks to your code I was able to make it much cleaner, scalable and I've actually made the search way better thanks to you.