Android : Bold Part of Text in a Textview when Text is Created during Runtime?

I'm making a Madlibs app. I need to bold the information the user entered in the output story. However, I am not quite sure how to bold only those certain strings within the textview. It is worth noting my app replaces all "wx" in a story with each string. That is how the the story is created. If someone can help me replace the all "wx" in the story with a bold string instead of a regular one it would be appreciated. Thank you.

public void gather() {

    ViewGroup layout = (ViewGroup) view.findViewById(R.id.anskey_clover);
    View[] views = new View[layout.getChildCount()];
    int[] ids = new int[layout.getChildCount()];

    for (int i = 0; i < layout.getChildCount(); i++) {
        ids[i] = layout.getChildAt(i).getId();
    }

    for (int i = 0; i < layout.getChildCount(); i++) {
        BootstrapEditText au = (BootstrapEditText) view.findViewById(ids[i]);
        stringbuffer.append(au.getText().toString() + "\n");

    }

    //setContentView(outLayout);
    //TextView outview = (TextView) view.findViewById(outviewid);
    //outview.setText(stringbuffer.toString());

}

public void postIt() {
    String str = "let's go to the park";
    String str2;
    String newstr = null;

    //setContentView(outLayout);
    TextView outview = (TextView) view.findViewById(outviewid);
    str = (String) outview.getText();
    stringviews = stringbuffer.toString().split("\n"); // turns the
                                                        // stringbuffer from
                                                        // getAllXml() into
                                                        // an array and
                                                        // assigns to
                                                        // stringviews.

    for (int i = 0; i < stringviews.length; i++) {

        str2 = stringviews[i];
        newstr = str.replaceFirst("wx", str2); // replaces all the "wx"s in
                                                // the
                                                // main_class_activity_out
                                                // textview with values from
                                                // strinvgviews.
        str = newstr;
    }
    outview.setText(newstr);
    ScrollView textScroll = (ScrollView) view.findViewById(R.id.scrollView1);
    //textScroll.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
    textScroll.getLayoutParams().width = LayoutParams.FILL_PARENT;
    textScroll.getLayoutParams().height = LayoutParams.FILL_PARENT;
    //textScroll.setPadding(0, 0, 0, 250);

    stringbuffer.delete(0, stringbuffer.length());

}