我在stackoverflow上使用了一个答案来编辑默认的android导航抽屉。
我的问题是在运行项目时收到此错误消息：
Caused by: java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.ListView
at uk.co.mrgyro.cropcirclelocatorandroid.NavigationDrawerFragment.onCreateView(NavigationDrawerFragment.java:97)
查看其他答案，这种接缝是由使用保留字引起的，但据我所知，我没有使用。
NavigationDrawerFragment.java
public class NavigationDrawerFragment extends Fragment {
private ImageView mDrawerImage;
private TextView mDrawerText;
/**
* 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 ListView mDrawerListView;
private View mFragmentContainerView;
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)
{
// need site names for list
String[] siteNames = getActivity().getResources().getStringArray(R.array.section_titles);
// inflate the parent view (the entire layout)
View view = inflater.inflate(R.layout.fragment_navigation_drawer, container, false);
// now grab the separate child views from inside it
mDrawerListView = (ListView) view.findViewById(R.id.nav_listView);
mDrawerImage = (ImageView) view.findViewById(R.id.nav_image);
mDrawerText = (TextView) view.findViewById(R.id.nav_text);
// configure the Views
mDrawerText.setText("Give it a name/title");
//mDrawerImage.setImageURI(...); // set your ImageView however you want, I just gave it one in XML
mDrawerListView.setOnItemClickListener((AdapterView.OnItemClickListener) this);
mDrawerListView.setAdapter(new ArrayAdapter<String>(getActionBar().getThemedContext(),
android.R.layout.simple_list_item_1, android.R.id.text1, siteNames));
mDrawerListView.setItemChecked(mCurrentSelectedPosition, true);
// and return the inflated view up the stack
return view;
}
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 webviews 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().supportInvalidateOptionsMenu(); // 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().supportInvalidateOptionsMenu(); // 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.main, 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);
actionBar.setHomeAsUpIndicator(R.drawable.ic_drawer);
}
private ActionBar getActionBar() {
return ((ActionBarActivity) getActivity()).getSupportActionBar();
}
/**
* 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);
}
}
fragment_navigation_drawer.xml
<?xml version="1.0" encoding="utf-8"?>
<!-- the root view is now a LinearLayout, all other Views are children of this -->
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:background="#cccc"
android:orientation="vertical"
android:id="@+id/listview2">
<!-- a separate section to go above the list -->
<LinearLayout
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:orientation="horizontal">
<!-- your image, you can set it later (see NavDrawerFrag) -->
<ImageView
android:id="@+id/nav_image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="15dp"
android:src="@android:drawable/ic_menu_myplaces"/>
<!-- a bit of test or a title to go with it -->
<TextView
android:id="@+id/nav_text"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:gravity="center_vertical"
android:text="Default text"/>
</LinearLayout>
<!-- some divider thing -->
<View
android:layout_width="match_parent"
android:layout_height="2dp"
android:padding="20dp"
android:background="#000000"/>
<!-- your ListView is now a child View -->
<ListView
android:id="@+id/nav_listView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:choiceMode="singleChoice"
android:divider="@android:color/transparent"
android:dividerHeight="0dp"/>
</LinearLayout>
答案 0 :(得分：1)
ListView和LinearLayout是不同的元素!!如果您想使用列表视图，只需在xml中添加<ListView .... />元素，而不是标识为<LinearLayout>的{{1}}
答案 1 :(得分：1)
而不是以下布局中的id
<LinearLayout
android:id="@+id/listview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:orientation="horizontal">
像这样改变
<LinearLayout
android:id="@+id/my_list_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:orientation="horizontal">
您正在使用listview作为Linear Layout的ID。将此更改为其他内容。因为listview是android中的关键字。