我在Android Studio上创建了导航抽屉活动，但我的主题是没有ActionBar（由于设计我使用了Toolbar小部件），它拒绝工作，给了我一个{{1指着这里：
java.lang.NullPointerException所以我尝试用其他上下文getter函数替换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),
}));
，但没有成功......
修改：根据要求： 堆栈跟踪：
getActionBar().getThemedContext()NavigationDrawerFragment.java：
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: FATAL EXCEPTION: main
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{br.net.beno.supercarrinho/br.net.beno.supercarrinho.AtividadePrincipal}: android.view.InflateException: Binary XML file line #19: Error inflating class fragment
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2255)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2309)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.access$700(ActivityThread.java:157)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1289)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:99)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.os.Looper.loop(Looper.java:176)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5319)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:511)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: Caused by: android.view.InflateException: Binary XML file line #19: Error inflating class fragment
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:710)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.rInflate(LayoutInflater.java:752)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:255)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at br.net.beno.supercarrinho.AtividadePrincipal.onCreate(AtividadePrincipal.java:52)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.Activity.performCreate(Activity.java:5326)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2218)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2309)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.access$700(ActivityThread.java:157)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1289)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:99)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.os.Looper.loop(Looper.java:176)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5319)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:511)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: Caused by: java.lang.NullPointerException
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at br.net.beno.supercarrinho.NavigationDrawerFragment.onCreateView(NavigationDrawerFragment.java:100)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:995)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1185)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentManagerImpl.addFragment(FragmentManager.java:1287)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2243)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:111)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:278)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:78)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:686)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.rInflate(LayoutInflater.java:752)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.inflate(LayoutInflater.java:495)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:255)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at br.net.beno.supercarrinho.AtividadePrincipal.onCreate(AtividadePrincipal.java:52)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.Activity.performCreate(Activity.java:5326)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2218)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2309)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.access$700(ActivityThread.java:157)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1289)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:99)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.os.Looper.loop(Looper.java:176)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5319)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:511)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
10-13 15:15:16.054 15849-15849/? E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
编辑2：
AtividadePrincipal.java
package br.net.beno.supercarrinho;
import android.support.v7.app.AppCompatActivity;
import android.app.Activity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
/**
* Fragment used for managing interactions for and presentation of a navigation drawer.
* See the <a href="https://developer.android.com/design/patterns/navigation-drawer.html#Interaction">
* design guidelines</a> for a complete explanation of the behaviors implemented here.
*/
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 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) {
mDrawerListView = (ListView) 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);
return mDrawerListView;
}
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().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.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 ((AppCompatActivity) 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);
}
}
编辑3：
activity_atividade_principal.xml：
package br.net.beno.supercarrinho;
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.widget.DrawerLayout;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import br.net.beno.supercarrinho.R;
import com.digits.sdk.android.Digits;
import com.twitter.sdk.android.Twitter;
import com.twitter.sdk.android.core.TwitterAuthConfig;
import com.twitter.sdk.android.core.TwitterCore;
import io.fabric.sdk.android.Fabric;
public class AtividadePrincipal extends AppCompatActivity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
// Note: Your consumer key and secret should be obfuscated in your source code before shipping.
private static final String TWITTER_KEY = "Dwt1PeE72Ht0znFw1WjVD7ym3";
private static final String TWITTER_SECRET = "NjxKx3fSfVI5DJ1xcuC5Eqy7AMPaJV5K1kzsCPYIdmxXWeNfoI";
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
private NavigationDrawerFragment mNavigationDrawerFragment;
/**
* Used to store the last screen title. For use in {@link #restoreActionBar()}.
*/
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TwitterAuthConfig authConfig = new TwitterAuthConfig(TWITTER_KEY, TWITTER_SECRET);
Fabric.with(this, new Digits(), new Twitter(authConfig));
setContentView(R.layout.activity_atividade_principal);
// Trocando a actionbar pela toolbar
Toolbar mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
// Gaveta de navegacao
mNavigationDrawerFragment = (NavigationDrawerFragment)
getSupportFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
}
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, FragmentoListaCompras.newInstance(position + 1))
.commit();
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getSupportActionBar();
// actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
// Only show items in the action bar relevant to this screen
// if the drawer is not showing. Otherwise, let the drawer
// decide what to show in the action bar.
getMenuInflater().inflate(R.menu.atividade_principal, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
如果您还需要更多信息，请询问。 ：）
答案 0 :(得分：0)
在您调用getActionBar()或getSupportActionbar()之前，您应将Toolbar设为ActionBar。
在调用Toolbar ActionBar之前，您是否已将Activity设置为onCreate Fragment中的onCreateView ？
Toolbar toolbar = (Toolbar) findViewById(R.id.your_toolbar_id);
setSupportActionBar(toolbar);
// setActionBar(toolbar); // if you are not using AppCompatActivity
修改
首先调用NavigationDrawerFragment的onCreateView ...
然后你可能会移动这些行：
// Trocando a actionbar pela toolbar
Toolbar mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
到片段：
private ActionBar getActionBar() {
AppCompatActivity activity = (AppCompatActivity) getActivity();
Toolbar mToolbar = (Toolbar) activity.findViewById(R.id.toolbar);
activity.setSupportActionBar(mToolbar);
return activity.getSupportActionBar();
}
上述代码可能仍有一些错误，但按此顺序，ActionBar不会为空。
答案 1 :(得分：0)
（适用（AppCompatActivity）getActivity（））。getSupportActionBar（） 操作栏是活动的一部分，而不是片段。观察片段类中访问操作栏的每一行。此外，在为活动扩展AppCompatActivity时，必须使用getSupportActionBar。
答案 2 :(得分：0)
据我所知，android.support.v4.widget.DrawerLayout应该只有两个子节点：主要内容和导航视图。我认为那里的工具栏是错误的。
答案 3 :(得分：0)
非常感谢这里的一些评论和回复，以及一些额外的研究，我能够启用它。
正如user5195185所指出的那样，似乎DrawerLayout 必须只有两个孩子：内容（它将附加您放置的任何内容的视图），以及抽屉（ListView）。在对Github进行一些搜索之后，我得到了this code。
所以我将Toolbar小部件的默认FrameLayout放在LinearLayout中，但我仍然遇到相同的NullPointer错误...
然后我检查了它的代码，我发现他们将主要活动作为上下文传递，因此我使用getActivity()代替getActionBar().getThemedContext()作为上下文，并且它有效！ / p>
之后，我找到了this reply，以允许栏位于ListView之上，并且我已经设置好了。
所以，我不知道它是否会导致未来的问题，但似乎是让工具栏和NavigationDrawer一起工作的正确方法。