我想在更改活動中的片段時更改片段活動的菜單項(abs)的可見性。片段是SherlockListFragments。Android:通過更改片段更改菜單項目的可見性
我想顯示/隱藏菜單項是紡紗廠創建於菜單創作:
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
MenuInflater inflater = getSupportMenuInflater();
IcsSpinner herbSortSpinner = new IcsSpinner(this, null, R.attr.actionDropDownStyle);
SpinnerAdapter herbSortSpinnerAdapter = ArrayAdapter.createFromResource(this, R.array.herb_sort_elements, android.R.layout.simple_spinner_dropdown_item);
herbSortSpinner.setAdapter(herbSortSpinnerAdapter);
herbSortSpinner.setOnItemSelectedListener(this);
herbSortSpinner.setId(HERB_SPINNER_ID);
menu.add(R.string.menu_sort).setActionView(herbSortSpinner).setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
IcsSpinner noteSortSpinner = new IcsSpinner(this, null, R.attr.actionDropDownStyle);
SpinnerAdapter noteSortSpinnerAdapter = ArrayAdapter.createFromResource(this, R.array.note_sort_elements, android.R.layout.simple_spinner_dropdown_item);
noteSortSpinner.setAdapter(noteSortSpinnerAdapter);
noteSortSpinner.setOnItemSelectedListener(this);
noteSortSpinner.setId(NOTE_SPINNER_ID);
menu.add(R.string.menu_sort).setActionView(noteSortSpinner).setVisible(false).setEnabled(false).setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
inflater.inflate(R.menu.activity_lexicon, menu);
menuHolder.setMenu(menu);
return true;
}
我切換片段的邏輯是:
public boolean onNavigationItemSelected(int position, long itemId) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
switch(position) {
case 0:
List<Herb> herbList = findHerbsByIntent(getHerbLocale());
HerbListFragment herbListFragment = new HerbListFragment();
herbListFragment.setListAdapter(new HerbListAdapter(this, getHerbLocale(), herbList));
fragmentTransaction.replace(R.id.fragment_container, herbListFragment, HERB_LIST_FRAGMENT_TAG);
//menuHolder.showHerbsSpinner();
break;
case 1:
SymptomListFragment symptomListFragment = new SymptomListFragment();
symptomListFragment.setListAdapter(new SymptomListAdapter(this, getDefaultSymptomLocale()));
fragmentTransaction.replace(R.id.fragment_container, symptomListFragment, SYMPTOM_LIST_FRAGMENT_TAG);
//menuHolder.showHerbsSpinner();
break;
case 2:
NoteRepository noteRepository = new NoteRepository(this);
List<Note> notes = noteRepository.getNoticables(ReferedType.HERB);
NoteListFragment noteListFragment = new NoteListFragment();
noteListFragment.setListAdapter(new NoteListAdapter(this, getHerbLocale(), notes));
fragmentTransaction.replace(R.id.fragment_container, noteListFragment, NOTE_LIST_FRAGMENT_TAG);
//menuHolder.showNotesSpinner();
break;
case 3:
FavoriteRepository favoriteRepository = new FavoriteRepository(this);
Set<Integer> favoriteHerbs = favoriteRepository.getFavorables(ReferedType.HERB);
List<Herb> favoriteHerbList = herbRepository.getHerbsByIds(favoriteHerbs, getHerbLocale());
FavoriteHerbListFragment favoriteHerbListFragment = new FavoriteHerbListFragment();
favoriteHerbListFragment.setListAdapter(new HerbListAdapter(this, getHerbLocale(), favoriteHerbList));
fragmentTransaction.replace(R.id.fragment_container, favoriteHerbListFragment, HERB_LIST_FRAGMENT_TAG);
//menuHolder.showHerbsSpinner();
break;
}
fragmentTransaction.commit();
return true;
}
我的第一個想法是:持有菜單對象在持有者類中,並在每次切換片段(在上面的每種情況下)中操作它。
static class MenuHolder {
private Menu mMenu;
void setMenu(Menu menu) {
mMenu = menu;
}
void showNotesSpinner() {
if (mMenu != null) {
mMenu.findItem(HERB_SPINNER_ID).setVisible(false).setEnabled(false);
mMenu.findItem(NOTE_SPINNER_ID).setVisible(true).setEnabled(true);
}
}
void showHerbsSpinner() {
if (mMenu != null) {
mMenu.findItem(NOTE_SPINNER_ID).setVisible(false).setEnabled(false);
mMenu.findItem(HERB_SPINNER_ID).setVisible(true).setEnabled(true);
}
}
}
我的問題是,有與給定的ID是哪個地方的活動沒有常量的菜單項。我在這裏得到一個NPE。有沒有人有一個想法,我可以解決這個問題?有沒有更好的方法來改變切換片段的菜單?
問候 卡斯滕
昨天幫了我自己。我已經清理了雜亂的代碼(在onCreate中僅對碎片進行實例化)並將菜單項直接存儲到持有者中。現在它像一個魅力。 – modebm