当我试图理解一个新概念时，我总是发现视觉例子很有帮助。

背景颜色

SpannableString spannableString = new SpannableString("Hello World!");
BackgroundColorSpan backgroundSpan = new BackgroundColorSpan(Color.YELLOW);
spannableString.setSpan(backgroundSpan, 0, spannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);

前景颜色

SpannableString spannableString = new SpannableString("Hello World!");
ForegroundColorSpan foregroundSpan = new ForegroundColorSpan(Color.RED);
spannableString.setSpan(foregroundSpan, 0, spannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);

结合

SpannableString spannableString = new SpannableString("Hello World!");
ForegroundColorSpan foregroundSpan = new ForegroundColorSpan(Color.RED);
BackgroundColorSpan backgroundSpan = new BackgroundColorSpan(Color.YELLOW);
spannableString.setSpan(foregroundSpan, 0, 8, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
spannableString.setSpan(backgroundSpan, 3, spannableString.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
textView.setText(spannableString);

进一步的研究

解释SPAN_EXCLUSIVE_EXCLUSIVE等Span标志的含义 Android Spanned, SpannedString, Spannable, SpannableString和CharSequence

这是一个帮助函数。当你有多种语言的时候非常有用!

private void setColor(TextView view, String fulltext, String subtext, int color) {
    view.setText(fulltext, TextView.BufferType.SPANNABLE);
    Spannable str = (Spannable) view.getText();
    int i = fulltext.indexOf(subtext);
    str.setSpan(new ForegroundColorSpan(color), i, i + subtext.length(), Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
}

下面的内容非常适合我

    tvPrivacyPolicy = (TextView) findViewById(R.id.tvPrivacyPolicy);
    String originalText = (String)tvPrivacyPolicy.getText();
    int startPosition = 15;
    int endPosition = 31;

    SpannableString spannableStr = new SpannableString(originalText);
    UnderlineSpan underlineSpan = new UnderlineSpan();
    spannableStr.setSpan(underlineSpan, startPosition, endPosition, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

    ForegroundColorSpan backgroundColorSpan = new ForegroundColorSpan(Color.BLUE);
    spannableStr.setSpan(backgroundColorSpan, startPosition, endPosition, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

    StyleSpan styleSpanItalic  = new StyleSpan(Typeface.BOLD);

    spannableStr.setSpan(styleSpanItalic, startPosition, endPosition, Spanned.SPAN_INCLUSIVE_EXCLUSIVE);

    tvPrivacyPolicy.setText(spannableStr);

以上代码的输出

通过传递String和Color在文本上设置颜色:

private String getColoredSpanned(String text, String color) {
  String input = "<font color=" + color + ">" + text + "</font>";
  return input;
}

通过调用下面的代码设置TextView / Button / EditText等文本:

TextView:

TextView txtView = (TextView)findViewById(R.id.txtView);

获取彩色字符串:

String name = getColoredSpanned("Hiren", "#800000");

在TextView上设置文本:

txtView.setText(Html.fromHtml(name));

Done

String text = "I don't like Hasina.";
textView.setText(spannableString(text, 8, 14));

private SpannableString spannableString(String text, int start, int end) {
    SpannableString spannableString = new SpannableString(text);
    ColorStateList redColor = new ColorStateList(new int[][]{new int[]{}}, new int[]{0xffa10901});
    TextAppearanceSpan highlightSpan = new TextAppearanceSpan(null, Typeface.BOLD, -1, redColor, null);

    spannableString.setSpan(highlightSpan, start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    spannableString.setSpan(new BackgroundColorSpan(0xFFFCFF48), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    spannableString.setSpan(new RelativeSizeSpan(1.5f), start, end, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);

    return spannableString;
}

输出:

您可以在Kotlin中使用扩展函数

fun CharSequence.colorizeText(
    textPartToColorize: CharSequence,
    @ColorInt color: Int
): CharSequence = SpannableString(this).apply {
    val startIndexOfText = this.indexOf(textPartToColorize.toString())
    setSpan(ForegroundColorSpan(color), startIndexOfText, startIndexOfText.plus(textPartToColorize.length), 0)
}

用法:

val colorizedText = "this text will be colorized"
val myTextToColorize = "some text, $colorizedText continue normal text".colorizeText(colorizedText,ContextCompat.getColor(context, R.color.someColor))
viewBinding.myTextView.text = myTextToColorize