如何在运行时在 android 中使文本的一部分加粗？

Let's say you have a TextView called etx. You would then use the following code:

final SpannableStringBuilder sb = new SpannableStringBuilder("HELLOO");
      

final StyleSpan bss = new StyleSpan(android.graphics.Typeface.BOLD); // Span to make text bold
final StyleSpan iss = new StyleSpan(android.graphics.Typeface.ITALIC); //Span to make text italic
sb.setSpan(bss, 0, 4, Spannable.SPAN_INCLUSIVE_INCLUSIVE); // make first 4 characters Bold
sb.setSpan(iss, 4, 6, Spannable.SPAN_INCLUSIVE_INCLUSIVE); // make last 2 characters Italic


etx.setText(sb);

我建议对 CDATA 使用 strings.xml 文件

<string name="mystring"><![CDATA[ <b>Hello</b> <i>World</i> ]]></string>

然后在 java 文件中:

TextView myTextView = (TextView) this.findViewById(R.id.myTextView);
myTextView.setText(Html.fromHtml( getResources().getString(R.string.mystring) ));

根据 Imran Rana 的回答，如果你需要将 StyleSpan应用到多个 TextView上，这里有一个通用的、可重用的方法，它支持多种语言(其中索引是可变的) :

void setTextWithSpan(TextView textView, String text, String spanText, StyleSpan style) {
SpannableStringBuilder sb = new SpannableStringBuilder(text);
int start = text.indexOf(spanText);
int end = start + spanText.length();
sb.setSpan(style, start, end, Spannable.SPAN_INCLUSIVE_INCLUSIVE);
textView.setText(sb);
}

像这样在 Activity中使用它:

@Override
protected void onCreate(Bundle savedInstanceState) {
// ...


StyleSpan boldStyle = new StyleSpan(Typeface.BOLD);
setTextWithSpan((TextView) findViewById(R.id.welcome_text),
getString(R.string.welcome_text),
getString(R.string.welcome_text_bold),
boldStyle);


// ...
}

strings.xml

<string name="welcome_text">Welcome to CompanyName</string>
<string name="welcome_text_bold">CompanyName</string>

结果:

欢迎来到 CompanyName

这里提供的答案是正确的，但不能在循环中调用，因为 StyleSpan对象是一个连续的 span (不是可以应用于多个 span 的样式)。使用相同的粗体 StyleSpan多次调用 setSpan将创建 一个大胆的跨度并在父范围内移动它。

In my case (displaying search results), I needed to make all instances of all the search keywords appear bold. This is what I did:

private static SpannableStringBuilder emboldenKeywords(final String text,
final String[] searchKeywords) {
// searching in the lower case text to make sure we catch all cases
final String loweredMasterText = text.toLowerCase(Locale.ENGLISH);
final SpannableStringBuilder span = new SpannableStringBuilder(text);


// for each keyword
for (final String keyword : searchKeywords) {
// lower the keyword to catch both lower and upper case chars
final String loweredKeyword = keyword.toLowerCase(Locale.ENGLISH);


// start at the beginning of the master text
int offset = 0;
int start;
final int len = keyword.length(); // let's calculate this outside the 'while'


while ((start = loweredMasterText.indexOf(loweredKeyword, offset)) >= 0) {
// make it bold
span.setSpan(new StyleSpan(Typeface.BOLD), start, start+len, SPAN_INCLUSIVE_INCLUSIVE);
// move your offset pointer
offset = start + len;
}
}


// put it in your TextView and smoke it!
return span;
}

请记住，如果一个关键字是另一个关键字的子字符串，则上面的代码不足以跳过双重加粗。例如，如果你在 “海里的鱼儿”中搜索 “ Fish Fi”，它将使 “鱼”加粗一次，然后是 “ Fi”部分。好的一面是，虽然效率低下，而且有点不受欢迎，但是它不会有视觉缺陷，因为显示的结果看起来仍然是这样

海里的鱼