android:background="?attr/colorPrimary"

TypedValue typedValue = new TypedValue();
mContext.getTheme().resolveAttribute(R.attr.colorPrimary,typedValue,true);
int colorPrimary = typedValue.data;//value.data里面存储着的就是获取到的colorPrimary的值

Resources res = getResources();
float fontSize = res.getDimension(R.dimen.font_size);