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)

TextView text = (TextView)findViewById(R.layout.textName);
text.setTypeface(null,Typeface.BOLD);

你有两个选择:

选项1(只适用于粗体、斜体和下划线):

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(Html.fromHtml(s));

选项2:

使用可伸缩帆布;它更复杂，但您可以动态修改文本属性(不仅是粗体/斜体，还包括颜色)。

试试这个:

TextView textview = (TextView)findViewById(R.id.textview_idname);
textview.setTypeface(null,Typeface.BOLD);

编程:

你可以通过编程方式使用setTypeface()方法:

下面是默认字体的代码

textView.setTypeface(null, Typeface.NORMAL);      // for Normal Text
textView.setTypeface(null, Typeface.BOLD);        // for Bold only
textView.setTypeface(null, Typeface.ITALIC);      // for Italic
textView.setTypeface(null, Typeface.BOLD_ITALIC); // for Bold and Italic

如果你想设置自定义字体:

textView.setTypeface(textView.getTypeface(), Typeface.NORMAL);      // for Normal Text
textView.setTypeface(textView.getTypeface(), Typeface.BOLD);        // for Bold only
textView.setTypeface(textView.getTypeface(), Typeface.ITALIC);      // for Italic
textView.setTypeface(textView.getTypeface(), Typeface.BOLD_ITALIC); // for Bold and Italic

XML:

你可以直接在<TextView />的XML文件中设置如下:

android:textStyle="normal"
android:textStyle="normal|bold"
android:textStyle="normal|italic"
android:textStyle="bold"
android:textStyle="bold|italic"

或者你可以设置你最喜欢的字体(从资产)。欲了解更多信息，请参阅链接