I thought that the chosen answer didn't provide a satisfactory result. I have written my own function which takes 2 strings; The full text and the part of the text you want to make bold.
It returns a SpannableStringBuilder with the 'textToBold' from 'text' bolded.
I find the ability to make a substring bold without wrapping it in tags useful.
/**
* Makes a substring of a string bold.
* @param text Full text
* @param textToBold Text you want to make bold
* @return String with bold substring
*/
public static SpannableStringBuilder makeSectionOfTextBold(String text, String textToBold){
SpannableStringBuilder builder=new SpannableStringBuilder();
if(textToBold.length() > 0 && !textToBold.trim().equals("")){
//for counting start/end indexes
String testText = text.toLowerCase(Locale.US);
String testTextToBold = textToBold.toLowerCase(Locale.US);
int startingIndex = testText.indexOf(testTextToBold);
int endingIndex = startingIndex + testTextToBold.length();
//for counting start/end indexes
if(startingIndex < 0 || endingIndex <0){
return builder.append(text);
}
else if(startingIndex >= 0 && endingIndex >=0){
builder.append(text);
builder.setSpan(new StyleSpan(Typeface.BOLD), startingIndex, endingIndex, 0);
}
}else{
return builder.append(text);
}
return builder;
}