Develop Reference

Not getting a new line in kotlin text view on android studio

fun SubmitOrder(view: View) {
/* pricing of coffee */
val total = quantity * 5
val s: String = ("$$total.00")
money.text = ("Total : $s\nThank You!").toString()
//This is calling On click listener
Toast.makeText(this, "order_Submitted", Toast.LENGTH_SHORT).show()
}
In this code, I need a new line before Thank You! in money.text but I am not getting any new line I am new in android development so, am not able to point out the mistake.

Let's go thru your code line by line:
val s: String = ("$$total.00")
s is a bad variable name, as it's not descriptive at all
you don't need the (braces)
the :String here is optional. In such an obvious case i would emit it.
A $ is a sign to the kotlin compiler to include the following variable. Therefore, you can't use the $ when you mean "US-Dollar". See this post on how to escape it
While ".00" works, it's no good style. I suggest you use string formatting as described here.
can be written as val s = "\$ ${String.format("%.2f", total)}"
you should wherever possible use string resources, but thats out of the scope of this answer
money.text = ("Total : $s\nThank You!").toString()
this is correct, but unnecessary verbose:
"Total : $s\nThank You!" is already a string, so there's no need to .toString()
braces are not needed
can be written as money.text = "Total : $s\nThank You!"

How to add decimal values to entries for chart using MpAndroidChart Library?

I'm trying to create a line chart in Android using MPAndroidChart Library and as entries I have values like 1200.10, 1300.70 and so on, but on my chart the values are rounded (1200, 1301), and I want to display the original values. How can I do that? I tried different solutions but couldn't solve the problem yet. I'm using the Kotlin language. Thanks!
for (item in reversedCashList) {
if (i <= daysNmb) {
var cashValue: String = transformDataForChart(item.value!!)
dataValsEntries.add(Entry(i, cashValue.toFloat()))
i++
}
}
Also, I'm using this formatter Class to format my values because the initial format is like 120.200,10 and I changed them to 120200.10 but this values is displayed as 120200. My Formatter Class:
private fun transformDataForChart(totalValue: String): String {
return if (totalValue.contains(".")) {
val test = totalValue.replace(".", "")
test.replace(",", ".")
} else {
totalValue.replace(",", ".")
}
}

You can try with BigDecimal, something like BigDecimal.valueOf(X).setScale(decimalPlace(usually 2), BigDecimal.ROUND_HALF_UP).floatValue()
The idea is that float cannot hold so many values as the Double, I've encountered this issue as some point as well, and I had to change everything to Double just to make it more easier to maintain... Therefor I don't think is a straight-forward method to keep everything you need in the float format.

How to check if a string has a specified character?

I am new to android studio and kotlin. I need to find a way to check if a string contains a char, which is, in this case, "/"
I want to form a piece of code in the following manner:
if (string input contains a character "/") = true {
<code>
}
else{
<code>
}
Please tell me how to do this, and if possible, give me the code I'll need to specify as the condition.

You can use contains, like this:
val a = "hello/"
val b = a.contains("/")
When the string has the character will return true.

Currency NumberFormat change the `format` behaviour after calling `parse`

I create a numberFormat to not return strings with decimals like:
val numberFormat = NumberFormat.getCurrencyInstance().apply {
minimumFractionDigits = 0
}
1. If I call format it returns fine
numberFormat.format(123) // "$123"
2. If I call parse with other value
numberFormat.parse("$333") // a number -> 333
3. And call format again with 123, the returned value contains the decimals! the format changed!.
numberFormat.format(123) // "$123.00"
Why? What can we do so it returns always with format without decimals like 1.?
I made a repo to reproduce it: https://github.com/danielgomezrico/test-numericformat-format-parse-error-sample.
It looks like it only fails on android not in java.
Take a look to MainActivity.kt

Never used NumberFormat so I am not sure why it acts like that... but one work around would be to make your numberFormat a class variable with a custom getter like so:
val numberFormat: NumberFormat
get() = NumberFormat.getCurrencyInstance().apply { maximumFractionDigits = 0 }
and then when you access it this way, it will apply the maximumFractionDigits each time

How to append 2 strings in Kotlin?

I am trying to concatenate 2 String but not sure how to go about it.
this is my code:
val word = R.string.word
and i'm trying to append it with "$currentPage/5" inside the setText("$currentPage/5")
i tried to make it in this way setText("$word $currentPage/5")
and this way setText("${R.string.value} $currentPage/5")
and it did not work , it only shows me numbers not the text

try to use this:
val word = getString(R.string.word)
text_view.text = "$word $currentPage/5"
If you want to edit your value (e.g. current page) wrap it with {}
E.g.
val word = getString(R.string.word)
text_view.text = "$word ${currentPage/5}"
Remember to use proper kotlin syntax

In Kotlin, the concatenation of string can be done by **interpolation/templates**.
val a = "Its"
val b = "Kotlin!"
val c = "$a $b"
The output will be Its Kotlin!
Or we can alson do concatenate using the **+ / plus() operator**:
val a = "String"
val b = "Concatenate"
val c = a + b
val d =a.plus(b)
print(c)
The output will be: StringConcatenate
print(d)
The output will be: StringConcatenate
Or you can concatenate using the StringBuilder which is a normal way to do that.

To concatenate two string, we could do
val concatenatedWord = "${resources.getString(R.string.value)}:
${number/3}."
If R.string.value was "The result" and number was 15, value of concatenatedWord will be "The result: 5."
Or we could also concatenate using the + operator or using StringBuilder.
But if you do
textView.text = "${resources.getString(R.string.value)}: ${number/3}."
AS will warn "Do not concatenate text displayed with setText." so, in the case of setting concatenated text in textview, consider using
String.format("%s: %d.", resources.getString(R.string.value):
number/3)

As a future resource and answer why the accepted answer works:-
String Templates:-
Strings may contain template expressions, i.e. pieces of code that are evaluated and whose results are concatenated into the string.
How to implement these?
A template expression should start with a dollar sign ($) and consists of either a simple name:
when the expression is a simple variable.
val i = 10
println("i = $i") // prints "i = 10"
or else arbitrary expression in curly braces:
val s = "abc"
println("$s.length is ${s.length}") // prints "abc.length is 3"
Note :- Templates are supported both inside raw strings and inside escaped strings.

val nameOfAnimal = "fish"
val speciesClass = "is an Aquatic Vertebrate"
println(nameOfAnimal.plus(speciesClass))
println(nameOfAnimal+speciesClass)
println("$nameOfAnimal $speciesClass")
Results:
fishis an Aquatic Vertebrate
fishis an Aquatic Vertebrate
fish is an Aquatic Vertebrate