如何在导航抽屉中创建子菜单
问题描述：
public class NavigationDrawerFragment extends Fragment {
/**
* Remember the position of the selected item.
*/
private static final String STATE_SELECTED_POSITION = "selected_navigation_drawer_position";
/**
* Per the design guidelines, you should show the drawer on launch until the
* user manually expands it. This shared preference tracks this.
*/
private static final String PREF_USER_LEARNED_DRAWER = "navigation_drawer_learned";
/**
* A pointer to the current callbacks instance (the Activity).
*/
private NavigationDrawerCallbacks mCallbacks;
/**
* Helper component that ties the action bar to the navigation drawer.
*/
private ActionBarDrawerToggle mDrawerToggle;
private DrawerLayout mDrawerLayout;
private ExpandableListView mDrawerListView;
private View mFragmentContainerView;
List<String> groupList;
List<String> childList;
Map<String, List<String>> laptopCollection;
private int mCurrentSelectedPosition = 0;
private boolean mFromSavedInstanceState;
private boolean mUserLearnedDrawer;
public NavigationDrawerFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Read in the flag indicating whether or not the user has demonstrated
// awareness of the
// drawer. See PREF_USER_LEARNED_DRAWER for details.
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(getActivity());
mUserLearnedDrawer = sp.getBoolean(PREF_USER_LEARNED_DRAWER, false);
if (savedInstanceState != null) {
mCurrentSelectedPosition = savedInstanceState
.getInt(STATE_SELECTED_POSITION);
mFromSavedInstanceState = true;
}
// Select either the default item (0) or the last selected item.
selectItem(mCurrentSelectedPosition);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Indicate that this fragment would like to influence the set of
// actions in the action bar.
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
createGroupList();
createCollection();
mDrawerListView = (ExpandableListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
final ExpandableListAdapter expListAdapter = new ExpandableListAdapter(
getActivity(), groupList, laptopCollection);
mDrawerListView.setAdapter(expListAdapter);
//setGroupIndicatorToRight();
mDrawerListView.setOnChildClickListener(new OnChildClickListener() {
public boolean onChildClick(ExpandableListView parent, View v,
int groupPosition, int childPosition, long id) {
final String selected = (String) expListAdapter.getChild(
groupPosition, childPosition);
Toast.makeText(getActivity().getBaseContext(), selected, Toast.LENGTH_LONG)
.show();
return true;
}
});
return mFragmentContainerView;
}
private void createGroupList() {
groupList = new ArrayList<String>();
groupList.add("HP");
groupList.add("Dell");
groupList.add("Lenovo");
groupList.add("Sony");
groupList.add("HCL");
groupList.add("Samsung");
}
private void createCollection() {
// preparing laptops collection(child)
String[] hpModels = { "HP Pavilion G6-2014TX", "ProBook HP 4540",
"HP Envy 4-1025TX" };
String[] hclModels = { "HCL S2101", "HCL L2102", "HCL V2002" };
String[] lenovoModels = { "IdeaPad Z Series", "Essential G Series",
"ThinkPad X Series", "Ideapad Z Series" };
String[] sonyModels = { "VAIO E Series", "VAIO Z Series",
"VAIO S Series", "VAIO YB Series" };
String[] dellModels = { "Inspiron", "Vostro", "XPS" };
String[] samsungModels = { "NP Series", "Series 5", "SF Series" };
laptopCollection = new LinkedHashMap<String, List<String>>();
for (String laptop : groupList) {
if (laptop.equals("HP")) {
loadChild(hpModels);
} else if (laptop.equals("Dell"))
loadChild(dellModels);
else if (laptop.equals("Sony"))
loadChild(sonyModels);
else if (laptop.equals("HCL"))
loadChild(hclModels);
else if (laptop.equals("Samsung"))
loadChild(samsungModels);
else
loadChild(lenovoModels);
laptopCollection.put(laptop, childList);
}
}
private void loadChild(String[] laptopModels) {
childList = new ArrayList<String>();
for (String model : laptopModels)
childList.add(model);
}
@SuppressWarnings("unused")
private void setGroupIndicatorToRight() {
/* Get the screen width */
DisplayMetrics dm = new DisplayMetrics();
getActivity().getWindowManager().getDefaultDisplay().getMetrics(dm);
int width = dm.widthPixels;
mDrawerListView.setIndicatorBounds(width - getDipsFromPixel(35), width
- getDipsFromPixel(5));
}
// Convert pixel to dip
public int getDipsFromPixel(float pixels) {
// Get the screen's density scale
final float scale = getResources().getDisplayMetrics().density;
// Convert the dps to pixels, based on density scale
return (int) (pixels * scale + 0.5f);
}
/*mDrawerListView = (ExpandableListView) inflater.inflate(
R.layout.fragment_navigation_drawer, container, false);
mDrawerListView
.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
selectItem(position);
}
});
mDrawerListView.setAdapter(new ArrayAdapter<String>(getActionBar()
.getThemedContext(),
android.R.layout.simple_list_item_activated_1,
android.R.id.text1, new String[] {
getString(R.string.title_section1),
getString(R.string.title_section2),
getString(R.string.title_section3), }));
mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);*/
public boolean isDrawerOpen() {
return mDrawerLayout != null
&& mDrawerLayout.isDrawerOpen(mFragmentContainerView);
}
/**
* Users of this fragment must call this method to set up the navigation
* drawer interactions.
*
* @param fragmentId
* The android:id of this fragment in its activity's layout.
* @param drawerLayout
* The DrawerLayout containing this fragment's UI.
*/
public void setUp(int fragmentId, DrawerLayout drawerLayout) {
mFragmentContainerView = getActivity().findViewById(fragmentId);
mDrawerLayout = drawerLayout;
// set a custom shadow that overlays the main content when the drawer
// opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
GravityCompat.START);
// set up the drawer's list view with items and click listener
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the navigation drawer and the action bar app icon.
mDrawerToggle = new ActionBarDrawerToggle(getActivity(), /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.navigation_drawer_open, /*
* "open drawer" description for
* accessibility
*/
R.string.navigation_drawer_close /*
* "close drawer" description for
* accessibility
*/
) {
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
if (!isAdded()) {
return;
}
getActivity().invalidateOptionsMenu(); // calls
// onPrepareOptionsMenu()
}
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
if (!isAdded()) {
return;
}
if (!mUserLearnedDrawer) {
// The user manually opened the drawer; store this flag to
// prevent auto-showing
// the navigation drawer automatically in the future.
mUserLearnedDrawer = true;
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(getActivity());
sp.edit().putBoolean(PREF_USER_LEARNED_DRAWER, true)
.apply();
}
getActivity().invalidateOptionsMenu(); // calls
// onPrepareOptionsMenu()
}
};
// If the user hasn't 'learned' about the drawer, open it to introduce
// them to the drawer,
// per the navigation drawer design guidelines.
if (!mUserLearnedDrawer && !mFromSavedInstanceState) {
mDrawerLayout.openDrawer(mFragmentContainerView);
}
// Defer code dependent on restoration of previous instance state.
mDrawerLayout.post(new Runnable() {
@Override
public void run() {
mDrawerToggle.syncState();
}
});
mDrawerLayout.setDrawerListener(mDrawerToggle);
}
private void selectItem(int position) {
mCurrentSelectedPosition = position;
if (mDrawerListView != null) {
mDrawerListView.setItemChecked(position, true);
}
if (mDrawerLayout != null) {
mDrawerLayout.closeDrawer(mFragmentContainerView);
}
if (mCallbacks != null) {
mCallbacks.onNavigationDrawerItemSelected(position);
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallbacks = (NavigationDrawerCallbacks) activity;
} catch (ClassCastException e) {
throw new ClassCastException(
"Activity must implement NavigationDrawerCallbacks.");
}
}
@Override
public void onDetach() {
super.onDetach();
mCallbacks = null;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(STATE_SELECTED_POSITION, mCurrentSelectedPosition);
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Forward the new configuration the drawer toggle component.
mDrawerToggle.onConfigurationChanged(newConfig);
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// If the drawer is open, show the global app actions in the action bar.
// See also
// showGlobalContextActionBar, which controls the top-left area of the
// action bar.
if (mDrawerLayout != null && isDrawerOpen()) {
inflater.inflate(R.menu.global, menu);
showGlobalContextActionBar();
}
super.onCreateOptionsMenu(menu, inflater);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
if (item.getItemId() == R.id.action_example) {
Toast.makeText(getActivity(), "Example action.", Toast.LENGTH_SHORT)
.show();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Per the navigation drawer design guidelines, updates the action bar to
* show the global app 'context', rather than just what's in the current
* screen.
*/
private void showGlobalContextActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setTitle(R.string.app_name);
}
private ActionBar getActionBar() {
return getActivity().getActionBar();
}
/**
* Callbacks interface that all activities using this fragment must
* implement.
*/
public static interface NavigationDrawerCallbacks {
/**
* Called when an item in the navigation drawer is selected.
*/
void onNavigationDrawerItemSelected(int position);
}
}
我收到错误，并且它不适用于可扩展列表视图。 我一直在为此工作五天，没有得到任何互联网帮助。 请帮帮我！如何在导航抽屉中创建子菜单
答
您必须在导航抽屉内使用可展开的ListView。
请参阅本Expandable List in Navigation Drawer
使用setGroupData()和setChildGroupData()功能从主要活动TI初始化列表。
你为什么不在这里添加代码链接不存在 – Shailesh