直接重寫(xiě)onBackpressed();

@Override

public void onBackPressed() {

????????backTask();

}

public void backTask() {

????????if (getSupportFragmentManager().getBackStackEntryCount() ==1) {

????????????????finish();

? ? ????}else {

????????????????getSupportFragmentManager().popBackStack();

? ????? }

}

如果fragmentManager的fragment數(shù)只有一個(gè)了,就finish(),不然就執(zhí)行popBackStack()用于返回上一個(gè)fragment;