这是我使用的Kotlin扩展函数

/**
 * Sets the specified Typeface Style on the first instance of the specified substring(s)
 * @param one or more [Pair] of [String] and [Typeface] style (e.g. BOLD, ITALIC, etc.)
 */
fun TextView.setSubstringTypeface(vararg textsToStyle: Pair<String, Int>) {
    val spannableString = SpannableString(this.text)
    for (textToStyle in textsToStyle) {
        val startIndex = this.text.toString().indexOf(textToStyle.first)
        val endIndex = startIndex + textToStyle.first.length

        if (startIndex >= 0) {
            spannableString.setSpan(
                StyleSpan(textToStyle.second),
                startIndex,
                endIndex,
                Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
            )
        }
    }
    this.setText(spannableString, TextView.BufferType.SPANNABLE)
}

用法:

text_view.text="something bold"
text_view.setSubstringTypeface(
    Pair(
        "something bold",
        Typeface.BOLD
    )
)

.

text_view.text="something bold something italic"
text_view.setSubstringTypeface(
    Pair(
        "something bold ",
        Typeface.BOLD
    ),
    Pair(
        "something italic",
        Typeface.ITALIC
    )
)

根据@mladj0ni的回答，我得到了下面的代码。问题是如果你使用String。格式，它剥离了HTML标记，所以你必须转义strings.xml中的括号符号:

strings.xml:

<string name="welcome_messages">Hello， %1$s!你有&lt;b>%2$d新消息&lt;/b>.</string> .</string> .

code.java:

String unspanned = String.format(Locale.US, "%s%s", getResources().getString(R.string. welcome_messages), 99);

Spanned spanned;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) {
    spanned = Html.fromHtml(unspanned, Html.FROM_HTML_MODE_LEGACY);
} else {
    spanned = Html.fromHtml(unspanned);
}

textView.setText(spanned);

它比SpannableStringBuilder简单。至于性能，如果只显示一个字符串，那么用户不会注意到解析它所花费的额外毫秒。

请在这里查看文档。

我认为所选择的答案并没有提供一个令人满意的结果。我写了自己的函数，它有两个字符串;全文和要加粗的文本部分。

它返回一个SpannableStringBuilder，带有从'text'中粗体的'textToBold'。

我发现使子字符串加粗而不用标签包装的能力很有用。

    /**
     * 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;
  }

只需在标签中添加这个

dangerouslySetInnerHTML={{__html: "<p>Your html text here.<p>"}}

虽然你可以使用Html.fromHtml()，你可以使用一个更原生的方法是SpannableStringBuilder，这篇文章可能会有帮助。

SpannableStringBuilder str = new SpannableStringBuilder("Your awesome text");
str.setSpan(new android.text.style.StyleSpan(android.graphics.Typeface.BOLD), INT_START, INT_END, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
TextView tv=new TextView(context);
tv.setText(str);

您可以使用此代码将部分文本设置为粗体。对于粗体html标签之间的任何内容，它都将使其加粗。

String myText = "make this <b>bold</b> and <b>this</b> too";
textView.setText(makeSpannable(myText, "<b>(.+?)</b>", "<b>", "</b>"));

public SpannableStringBuilder makeSpannable(String text, String regex, String startTag, String endTag) {

            StringBuffer sb = new StringBuffer();
            SpannableStringBuilder spannable = new SpannableStringBuilder();

            Pattern pattern = Pattern.compile(regex);
            Matcher matcher = pattern.matcher(text);
            while (matcher.find()) {
                sb.setLength(0);
                String group = matcher.group();
                String spanText = group.substring(startTag.length(), group.length() - endTag.length());
                matcher.appendReplacement(sb, spanText);

                spannable.append(sb.toString());
                int start = spannable.length() - spanText.length();

                spannable.setSpan(new android.text.style.StyleSpan(android.graphics.Typeface.BOLD), start, spannable.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
            }
            sb.setLength(0);
            matcher.appendTail(sb);
            spannable.append(sb.toString());
            return spannable;
        }