TextView protocol = findViewById(R.id.tv_protocol);
SpannableStringBuilder builder = new SpannableStringBuilder(protocol.getText().toString());
ForegroundColorSpan foregroundColorSpan = new ForegroundColorSpan(Color.BLUE);
UnderlineSpan underlineSpan = new UnderlineSpan();
builder.setSpan(foregroundColorSpan, 8, 16, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
builder.setSpan(underlineSpan, 8, 16, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
protocol.setText(builder);
参考资料：
https://blog.csdn.net/duoduo_11011/article/details/71084765
