create a button for change the font

create a button for change the font

i wrote this code to create a button for changing font but i isn't work
and if condition never became true what is my problem?
font.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
Typeface mitra = Typeface.createFromAsset(getAssets(),
"font/MitraB.ttf");
if (WBC.getTypeface() == mitra) {
Typeface tabssom = Typeface.createFromAsset(getAssets(),
"font/tabassom.ttf");
WBC.setTypeface(tabssom);
} else {
WBC.setTypeface(mitra);
}
}
});