After looking at the Documentation of the Dateformat class, no other parameter seems to do what you want. This "uppercase" information seems to come directly from when you select the locale pt_BR
.
However, you can do a function for such:
String tornarMesMaiusculo(String data){
List<String> palavras = data.split(" ");
palavras.last = "${palavras.last[0].toUpperCase()}${palavras.last.substring(1)}";
return (palavras.join(" "));
}
If you prefer, you can make a extension
to be able to call directly:
extension mesMaiusculo on String{
String tornarMesMaiusculo(){
List<String> palavras = this.split(" ");
palavras.last = "${palavras.last[0].toUpperCase()}${palavras.last.substring(1)}";
return (palavras.join(" "));
}
}
So you can call directly:
String dateFormate = '25 de março';
print (dateFormate.tornarMesMaiusculo()); // imprime "25 de Março"
Do not forget that a function of this type assumes the String to be this specific way, and you should take precautions not to call it with empty strings for example.