TextView text = (TextView)findViewById(R.id.THE_TEXTVIEW_ID);

现在设置textview属性..

text.setTypeface(null, Typeface.BOLD);  //-- for only bold the text
text.setTypeface(null, Typeface.BOLD_ITALIC);  //-- for  bold & italic the text
text.setTypeface(null, Typeface.ITALIC);  // -- for  italic the text

textView.setTypeface(null, Typeface.BOLD_ITALIC);
textView.setTypeface(null, Typeface.BOLD);
textView.setTypeface(null, Typeface.ITALIC);
textView.setTypeface(null, Typeface.NORMAL);

保持以前的字体

textView.setTypeface(textView.getTypeface(), Typeface.BOLD_ITALIC)

//leveraging the extension functions
fun TextView.makeBold(){
    this.setTypeface(this.typeface,Typeface.BOLD)
}


yourTextView.makeBold()

在AndroidX中使用简化标签时，请考虑使用HtmlCompat.fromHtml()

String s = "<b>Bolded text</b>, <i>italic text</i>, even <u>underlined</u>!"    
TextView tv = (TextView)findViewById(R.id.THE_TEXTVIEW_ID);
tv.setText(HtmlCompat.fromHtml(s, FROM_HTML_MODE_LEGACY));

textView.setTypeface(null, Typeface.BOLD_ITALIC);
textView.setTypeface(null, Typeface.BOLD);
textView.setTypeface(null, Typeface.ITALIC);
textView.setTypeface(null, Typeface.NORMAL);

保持以前的字体

textView.setTypeface(textView.getTypeface(), Typeface.BOLD_ITALIC)

很简单，如果你想让文本加粗。 将这一行写在布局中的文本视图属性中

android:textStyle="bold"