Why hasn't the string been replaced when it is from string resource file in Kotlin?

When I use Code A, I get the original string ,why?

Code B can replace string both ${myObject.status} and ${myObject.name}, the result is OK.

${myObject.status}

${myObject.name}

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Code A

<string name="DetailsOfWiFiDef">The WiFi status is ${myObject.status},
the name of WiFi is ${myObject.name}nn
</string>

val myObject=getIt()
val s=mContext.getString(R.string.DetailsOfWiFiDef)
val sb = StringBuilder()
sb.append(s) //The string keep original


Code B

val myObject=getIt()
val k="The WiFi status is ${myObject.status},the name of WiFi is ${myObject.name} n"
val sb = StringBuilder()
sb.append(k) //It has been replaced


1 Answer
1

Kotlin compiler converts string literals into StringBuilder chain at compile time:

StringBuilder

// code in Kotlin
val k = "The WiFi status is ${myObject.status},the name of WiFi is ${myObject.name} n"

// is converted into equivalent of code in Java
String k = new StringBuilder("The WiFi status is ").append(myObject.getStatus()).append(",the name of WiFi is ").append(myObject.getName()).append(" n");


If you load through resources there's no conversion, it's used as is. However you can use formattable string resource:

<string name="DetailsOfWiFiDef">The WiFi status is %1$s,
the name of WiFi is %2$snn
</string>


Then inject arguments when reading string (Android Studio even corrects You if you proide too many arguments or wrong type in real time):

val s=mContext.getString(R.string.DetailsOfWiFiDef, myObject.status, myObject.name)


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