First Part **Second Part should be Bold** last Part

此文本应该使用SpannableString进行更改

import android.graphics.Typeface.BOLD
import android.text.Spannable
import android.text.Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
import android.text.SpannableString
import android.text.style.BackgroundColorSpan
import android.text.style.ForegroundColorSpan
import android.text.style.StyleSpan

val firstPart = "First Part  "
val secondPart = "Second Part should be Bold"
val thirdPart = "  last Part"
val finalString = firstPart + secondPart + thirdPart

val sb: Spannable = SpannableString(finalString).also {
                // ... Change text Colour
                it.setSpan(
                    ForegroundColorSpan(getColor(requireContext(), R.color.pink)),
                    finalString.indexOf(secondPart),
                    finalString.indexOf(secondPart) + secondPart.length,
                    SPAN_EXCLUSIVE_EXCLUSIVE
                )
                // ... Make the text Bold
                it.setSpan(
                    StyleSpan(BOLD),
                    finalString.indexOf(secondPart),
                    finalString.indexOf(secondPart) + secondPart.length,
                    SPAN_EXCLUSIVE_EXCLUSIVE
                )
                // ... Change Background Colour
                it.setSpan(
                    BackgroundColorSpan(getColor(requireContext(), R.color.lightPink)),
                    finalString.indexOf(secondPart) - 1,
                    finalString.indexOf(secondPart) + secondPart.length + 1,
                    SPAN_EXCLUSIVE_EXCLUSIVE
                )
}

yourTextView.text = sb

现在您可以使用CodeView库轻松地突出显示不同颜色的模式，例如，用您只需要编写的蓝色突出显示文本中的所有url

CodeView codeView = findViewById(R.id.codeview);
codeView.addSyntaxPattern(Patterns.WEB_URL, Color.BLUE);
codeView.setTextHighlighted(text);

CodeView存储库URL: https://github.com/amrdeveloper/codeview

从开发人员文档中，更改一个可伸缩对象的颜色和大小:

1-创建类:

    class RelativeSizeColorSpan(size: Float,@ColorInt private val color: Int): RelativeSizeSpan(size) {

    override fun updateDrawState(textPaint: TextPaint?) {
        super.updateDrawState(textPaint)
        textPaint?.color = color
    } 
}

2 .使用该类创建你的spannable:

    val spannable = SpannableStringBuilder(titleNames)
spannable.setSpan(
    RelativeSizeColorSpan(1.5f, Color.CYAN), // Increase size by 50%
    titleNames.length - microbe.name.length, // start
    titleNames.length, // end
    Spannable.SPAN_EXCLUSIVE_INCLUSIVE
)

设置你的TextView的文本跨度，并为你的文本定义一个ForegroundColorSpan。

TextView textView = (TextView)findViewById(R.id.mytextview01);    
Spannable wordtoSpan = new SpannableString("I know just how to whisper, And I know just how to cry,I know just where to find the answers");          
wordtoSpan.setSpan(new ForegroundColorSpan(Color.BLUE), 15, 30, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);    
textView.setText(wordtoSpan);

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

如果你想要更多的控制，你可能想检查TextPaint类。下面是如何使用它:

final ClickableSpan clickableSpan = new ClickableSpan() {
    @Override
    public void onClick(final View textView) {
        //Your onClick code here
    }

    @Override
    public void updateDrawState(final TextPaint textPaint) {
        textPaint.setColor(yourContext.getResources().getColor(R.color.orange));
        textPaint.setUnderlineText(true);
    }
};