Replace certain String with Spans without HTML

I'm trying to replace a certain string with a span.

For example I have this String:

String s = "redHello greenWorld";

I wanna replace "red" with:

modifiedText.setSpan(new ForegroundColorSpan(Color.parseColor("#FF0000")), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

and "green" with:

modifiedText.setSpan(new ForegroundColorSpan(Color.parseColor("#00FF00")), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

So I create modifiedText this way:

Spannable modifiedText = new SpannableString(s);

How can I replace a certain String with a Span without HTML?

Since you asked about cutting out - I hope this is what you meant (new code)

//setup
String text = "redHello greenWorld redTest";
List<String> colors = new ArrayList<>();
colors.add("red");
colors.add("green");

//finding the positions
List<Integer> pos = new ArrayList<>();
List<String> colorPositions = new ArrayList<>();
for (String toFind: colors) {
    Pattern word = Pattern.compile(toFind);
    Matcher match = word.matcher(text);
    while (match.find()) {
       pos.add(match.start());
       colorPositions.add(toFind);
    }
}

//replacing
for (String element : colors) {
    text = text.replace(element, "");
}

Now you need to sort the list

//really inefficient sorting
boolean sorted = false;
Integer temp_pos;
String temp_color;
Integer[] sorted_pos = pos.toArray(Integer[]::new);
String[] sorted_color = colorPositions.toArray(String[]::new);
while(!sorted) {
    sorted = true;
    for (int i = 0; i < sorted_pos.length - 1; i++) {
        if (sorted_pos[i] > sorted_pos[i + 1]) {
            temp_pos = sorted_pos[i];
            temp_color = sorted_color[i];
            sorted_pos[i] = sorted_pos[i + 1];
            sorted_color[i] = sorted_color[i + 1];
            sorted_pos[i + 1] = temp_pos;
            sorted_color[i + 1] = temp_color;
            sorted = false;
        }
    }
}

And subtract the "red" and "green"

//subtracting
for (int i = 1; i < sorted_pos.length; i++) {
    for (int j = i; j < sorted_pos.length; j++) {
        sorted_pos[j] -= sorted_color[i - 1].length();
    }
}

The end result now contains [0, 6, 12], the starting indexes of the spans - now you only need to iterate through the output and set the spans (the colors to the spans are in sorted_color)