wtsang02答案是最好的方法，因为，Html.fromHtml("")现在已弃用。这里我要稍微加强一下，以方便那些在动态地将第一个单词加粗方面有问题的人，不管句子的大小。

首先让我们创建一个方法来获取第一个单词:

 private String getFirstWord(String input){

    for(int i = 0; i < input.length(); i++){

        if(input.charAt(i) == ' '){

            return input.substring(0, i);
        }
    }

    return input;
}

现在假设你有一个像这样的长字符串:

String sentence = "friendsAwesomeName@gmail.com want's to be your friend!"

你希望你的句子是yourAwesomeName@gmail.com想成为你的朋友! 你所要做的就是-获取firstWord并获取它的长度以使firstWord加粗，就像这样:

String myFirstWord = getFirstWord(sentence);
int start = 0; // bold will start at index 0
int end = myFirstWord.length(); // and will finish at whatever the length of your first word

现在按照wtsang02的步骤来做，就像这样:

SpannableStringBuilder fancySentence = new SpannableStringBuilder(sentence);
fancySentence.setSpan(new android.text.style.StyleSpan(Typeface.BOLD), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(fancySentence);

就是这样!现在你应该可以在长句或短句中加粗任意大小的单词了。

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;
        }

当在list/recycler中搜索char时，使字符串的第一个char可扩展

拉维和阿杰

以前突出显示像这样，但我想像下面

ravi和ajay OR ravi和ajay

为此，我搜索单词长度，如果它等于1，我将主字符串分离成单词并计算单词开始位置，然后我搜索单词以char开头。

 public static SpannableString colorString(int color, String text, String... wordsToColor) {
    SpannableString coloredString = new SpannableString(text);

    for (String word : wordsToColor) {

        Log.e("tokentoken", "-wrd len-" + word.length());
        if (word.length() !=1) {
            int startColorIndex = text.toLowerCase().indexOf(word.toLowerCase());
            int endColorIndex = startColorIndex + word.length();
            try {
                coloredString.setSpan(new ForegroundColorSpan(color), startColorIndex, endColorIndex,
                        Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

            } catch (Exception e) {
                e.getMessage();
            }
        } else {
            int start = 0;

            for (String token : text.split("[\u00A0 \n]")) {
                if (token.length() > 0) {
                    start = text.indexOf(token, start);
                   // Log.e("tokentoken", "-token-" + token + "   --start--" + start);
                    char x = token.toLowerCase().charAt(0);
                    char w = word.toLowerCase().charAt(0);
                   // Log.e("tokentoken", "-w-" + w + "   --x--" + x);

                    if (x == w) {
                        // int startColorIndex = text.toLowerCase().indexOf(word.toLowerCase());
                        int endColorIndex = start + word.length();
                        try {
                            coloredString.setSpan(new ForegroundColorSpan(color), start, endColorIndex,
                                    Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

                        } catch (Exception e) {
                            e.getMessage();
                        }
                    }
                }
            }

        }

    }

    return coloredString;
}

这是我的完整的解决方案，动态字符串值与大小写检查。

/**
 * Makes a portion of String formatted in BOLD.
 *
 * @param completeString       String from which a portion needs to be extracted and formatted.<br> eg. I am BOLD.
 * @param targetStringToFormat Target String value to format. <br>eg. BOLD
 * @param matchCase Match by target character case or not. If true, BOLD != bold
 * @return A string with a portion formatted in BOLD. <br> I am <b>BOLD</b>.
 */
public static SpannableStringBuilder formatAStringPortionInBold(String completeString, String targetStringToFormat, boolean matchCase) {
    //Null complete string return empty
    if (TextUtils.isEmpty(completeString)) {
        return new SpannableStringBuilder("");
    }

    SpannableStringBuilder str = new SpannableStringBuilder(completeString);
    int start_index = 0;

    //if matchCase is true, match exact string
    if (matchCase) {
        if (TextUtils.isEmpty(targetStringToFormat) || !completeString.contains(targetStringToFormat)) {
            return str;
        }

        start_index = str.toString().indexOf(targetStringToFormat);
    } else {
        //else find in lower cases
        if (TextUtils.isEmpty(targetStringToFormat) || !completeString.toLowerCase().contains(targetStringToFormat.toLowerCase())) {
            return str;
        }

        start_index = str.toString().toLowerCase().indexOf(targetStringToFormat.toLowerCase());
    }

    int end_index = start_index + targetStringToFormat.length();
    str.setSpan(new StyleSpan(BOLD), start_index, end_index, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    return str;
}

如。completeString = "I am BOLD"

情况下,我 if *targetStringToFormat* = "bold" and *matchCase* = true

返回“I am BOLD”(因为BOLD != BOLD)

案例二世 if *targetStringToFormat* = "bold" and *matchCase* = false

返回“I am BOLD”

应用:

myTextView.setText(formatAStringPortionInBold("I am BOLD", "bold", false))

希望有帮助!

如果你正在使用Kotlin，使用core-ktx会变得更容易，因为它提供了一种领域特定语言(DSL)来做这件事:

val string: SpannedString = buildSpannedString {
    bold {
        append("foo")
    }
    append("bar")     
}

它提供的更多选项有:

append("Hello There")
bold {
    append("bold")
    italic {
        append("bold and italic")
        underline {
            append("then some text with underline")
        }
    }
}

最后，你只需:

textView.text = string

下面是我如何使用正则表达式和Kotlin来做到这一点

val BOLD_SPAN = StyleSpan(Typeface.BOLD)

    fun TextView.boldMatches(regexString: String) {
        this.applyStyleSpanToMatches(regexString, BOLD_SPAN)
    }
    

fun TextView.applyStyleSpanToMatches(regexString: String, span: StyleSpan){
        this.text = this.text.toString().applyStyleSpanToMatches(regexString, span)
        }

        fun String.applyStyleSpanToMatches(regexString: String, span: StyleSpan): Spannable {
            val result = SpannableString.valueOf(this)
            if(regexString.isEmpty()) return result
            val pattern = try{
                Pattern.compile(regexString)
            } catch (e: PatternSyntaxException){
                return result
            }
            val matcher = pattern.matcher(result)
            while (matcher.find()) {
                val start = matcher.start()
                val end = matcher.end()
                result.setSpan(span, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
            }
            return result
        }

使用问句 它可以这样应用:

txtResult.boldMatches(id)