有的语句我理解不了啊？？求大神帮忙
mTab0x(x为数字0,1 2 3)为空时和不为空，怎么理解？？求指教
if (mTab02 == null) {
mTab02 = new FrdFragment();
transaction.add(R.id.id_content, mTab02);
}else
{
transaction.show(mTab02);
}
为什么mTab01为空时才隐藏啊？？我理解不了啊
private void hideFragment(FragmentTransaction transaction) {
if (mTab01 != null) {
transaction.hide(mTab01);
}
if (mTab02 != null) {
transaction.hide(mTab02);
}
if (mTab03 != null) {
transaction.hide(mTab03);
}
if (mTab04 != null) {
transaction.hide(mTab04);
}
}
