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。

我创建了一个静态方法来设置文本粗体的TextView和EditText部分

public static void boldPartOfText(View mView, String contentData, int startIndex, int endIndex){
        if(!contentData.isEmpty() && contentData.length() > endIndex) {
            final SpannableStringBuilder sb = new SpannableStringBuilder(contentData);

            final StyleSpan bss = new StyleSpan(Typeface.BOLD); // Span to make text bold
            final StyleSpan iss = new StyleSpan(Typeface.NORMAL); //Span to make text normal
            sb.setSpan(iss, 0, startIndex, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
            sb.setSpan(bss, startIndex, endIndex, Spannable.SPAN_INCLUSIVE_INCLUSIVE); // make first 4 characters Bold
            sb.setSpan(iss,endIndex, contentData.length()-1, Spanned.SPAN_INCLUSIVE_INCLUSIVE);

            if(mView instanceof TextView)
               ((TextView) mView).setText(sb);
            else if(mView instanceof EditText)
               ((EditText) mView).setText(sb);

        }
    }

另一个更定制的代码

  /*typeFaceStyle can be passed as 

    Typeface.NORMAL = 0;
    Typeface.BOLD = 1;
    Typeface.ITALIC = 2;
    Typeface.BOLD_ITALIC = 3;*/

    public static void boldPartOfText(View mView, String contentData, int startIndex, int endIndex,int typeFaceStyle){
        if(!contentData.isEmpty() && contentData.length() > endIndex) {
            final SpannableStringBuilder sb = new SpannableStringBuilder(contentData);

            final StyleSpan bss = new StyleSpan(typeFaceStyle); // Span to make text bold
            final StyleSpan iss = new StyleSpan(Typeface.NORMAL); //Span to make text italic
            sb.setSpan(iss, 0, startIndex, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
            sb.setSpan(bss, startIndex, endIndex, Spannable.SPAN_INCLUSIVE_INCLUSIVE); // make first 4 characters Bold
            sb.setSpan(iss,endIndex,contentData.length()-1,Spanned.SPAN_INCLUSIVE_INCLUSIVE);

            if(mView instanceof TextView)
                ((TextView) mView).setText(sb);
            else if(mView instanceof EditText)
                ((EditText) mView).setText(sb);
        }
    }

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
    )
)

这里有一个更好的解决方案，如果你想使多个文本粗体。我改进了Eitan的代码。谢谢你搞清楚。

public static SpannableStringBuilder makeSectionOfTextBold(String text, String... textToBold) {
    SpannableStringBuilder builder = new SpannableStringBuilder(text);

    for (String textItem :
            textToBold) {
        if (textItem.length() > 0 && !textItem.trim().equals("")) {
            //for counting start/end indexes
            String testText = text.toLowerCase(Locale.US);
            String testTextToBold = textItem.toLowerCase(Locale.US);
            int startingIndex = testText.indexOf(testTextToBold);
            int endingIndex = startingIndex + testTextToBold.length();

            if (startingIndex >= 0 && endingIndex >= 0) {
                builder.setSpan(new StyleSpan(Typeface.BOLD), startingIndex, endingIndex, 0);
            }
        }
    }

    return builder;
}

它很简单，就像这样关闭指定的文本，例如<b>"你的文本在这里:"</b>

<string name="headquarters">"<b>"Headquarters:"</b>" Mooresville, North Carolina, U.S.</string>

结果: 总部:美国北卡罗来纳州穆尔斯维尔

如果你想使用XML中的字符串，你可以这样做:

xml(“CDATA”部分很重要，否则它将不起作用)

<string name="test">
     <![CDATA[
 <b>bold!</b> normal
    ]]>
</string>

布局文件

<FrameLayout
    xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView" android:layout_width="wrap_content" android:layout_height="wrap_content"
        android:layout_gravity="center" />

</FrameLayout>

code

textView.text = HtmlCompat.fromHtml(getString(R.string.test), HtmlCompat.FROM_HTML_MODE_LEGACY)