我按照本教程制作导航抽屉：
https://github.com/codepath/android_guides/wiki/Fragment-Navigation-Drawer
我的一个片段是如下定义的地图：
XML
<fragment android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.MapFragment" />
<FrameLayout android:orientation="vertical" xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
/*Some texts and buttons */
</FrameLayout>
</RelativeLayout>
爪哇
public class MapsFragment extends Fragment implements AsyncResponse {
private View mView;
private GoogleMap mMap;
private LayoutInflater mInflater;
private Bundle savedInstanceState;
private CustomButton mCancelButton;
private CustomButton mPeekButton;
private boolean mActivityPaused;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mPeeks = new ArrayList();
mGson = new Gson();
mInflater = inflater;
mIsPaneOpen = false;
mMarkerMap = new HashMap();
if (mView != null) {
ViewGroup parent = (ViewGroup) mView.getParent();
if (parent != null)
parent.removeView(mView);
}
try {
mView = mInflater.inflate(R.layout.activity_maps, container, false);
} catch (InflateException e) {
e.printStackTrace();
}
setUpMapIfNeeded();
mCancelButton = (CustomButton) mView.findViewById(R.id.bt_cancel);
return mView;
}
public void setUpMapIfNeeded(){
if (mMap == null){
mMap = ((MapFragment) getActivity().getFragmentManager().findFragmentById(R.id.map)).getMap();
if (mMap != null)
setUpMap();
}
}
private void setUpMap() {
mMap.setMyLocationEnabled(true);
//Some code
}
}
我自愿删除一些不相关的代码。 然后我有主要活动：
XML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- The ActionBar -->
<include
layout="@layout/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- The main content view -->
<FrameLayout
android:id="@+id/flContent"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
<!-- The navigation drawer -->
<android.support.design.widget.NavigationView
android:id="@+id/nvView"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:background="@android:color/white"
app:menu="@menu/drawer_view" />
</android.support.v4.widget.DrawerLayout>
</LinearLayout>
爪哇
public class MainActivity extends AppCompatActivity {
/**
* Fragment managing the behaviors, interactions and presentation of the navigation drawer.
*/
//Manager de Fragment
DrawerLayout mDrawer; // Declaring DrawerLayout
Toolbar mToolbar;
Fragment currentFrag;
FragmentManager mFragmentManager;
Fragment mMapFragment;
Fragment mUserFragment;
Fragment mThirdFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mFragmentManager = getSupportFragmentManager();
mMapFragment = new MapsFragment();
mUserFragment = new UserFragment();
mThirdFragment = new ThirdFragment();
//Initializing the first Fragment
mFragmentManager.beginTransaction().replace(R.id.flContent, new MapsFragment()).commit();
// Set a Toolbar to replace the ActionBar.
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
// Find our drawer view
mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
// Set the menu icon instead of the launcher icon.
final ActionBar ab = getSupportActionBar();
ab.setHomeAsUpIndicator(R.drawable.ic_menu);
ab.setDisplayHomeAsUpEnabled(true);
// Find our drawer view
NavigationView nvDrawer = (NavigationView) findViewById(R.id.nvView);
// Setup drawer view
setupDrawerContent(nvDrawer);
}
//First We Declare Titles And Icons For Our Navigation Drawer List View
//This Icons And Titles Are holded in an Array as you can see
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
switch (item.getItemId()) {
case android.R.id.home:
mDrawer.openDrawer(GravityCompat.START);
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
}
private void setupDrawerContent(NavigationView navigationView) {
navigationView.setNavigationItemSelectedListener(
new NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
selectDrawerItem(menuItem);
return true;
}
});
}
public void selectDrawerItem(MenuItem menuItem) {
// Create a new fragment and specify the planet to show based on
// position
Fragment fragment = null;
switch(menuItem.getItemId()) {
case R.id.nav_map:
fragment = mMapFragment;
break;
case R.id.nav_profile:
fragment = mUserFragment;
break;
case R.id.nav_nav_settings:
fragment = mThirdFragment;
break;
default:
fragment = mMapFragment;
}
// Insert the fragment by replacing any existing fragment
mFragmentManager.beginTransaction().replace(R.id.flContent, fragment).commit();
// Highlight the selected item, update the title, and close the drawer
menuItem.setChecked(true);
setTitle(menuItem.getTitle());
mDrawer.closeDrawers();
}
}
问题是，当我第一次附加de MapFragment时没问题，Activity显示地图。但当我试图通过导航抽屉去另一个片段然后回到地图片段我有这个例外：
07-19 16:04:25.710 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ android.view.InflateException: Binary XML file line #12: Error inflating class fragment
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:770)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.view.LayoutInflater.rInflate(LayoutInflater.java:813)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.view.LayoutInflater.inflate(LayoutInflater.java:511)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.view.LayoutInflater.inflate(LayoutInflater.java:415)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at fr.yougraph.homelesspasseul.fragment.MapsFragment.onCreateView(MapsFragment.java:93)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:458)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:739)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.os.Looper.loop(Looper.java:145)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5944)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at java.lang.reflect.Method.invoke(Native Method)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:372)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1389)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ Caused by: java.lang.IllegalArgumentException: Binary XML file line #12: Duplicate id 0x7f0e0099, tag null, or parent id 0x7f0e0098 with another fragment for com.google.android.gms.maps.MapFragment
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2135)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.app.Activity.onCreateView(Activity.java:5610)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v7.app.AppCompatDelegateImplV11.callActivityOnCreateView(AppCompatDelegateImplV11.java:41)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v7.app.AppCompatDelegateImplV7.onCreateView(AppCompatDelegateImplV7.java:826)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.support.v4.view.LayoutInflaterCompatHC$FactoryWrapperHC.onCreateView(LayoutInflaterCompatHC.java:44)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.view.LayoutInflater$FactoryMerger.onCreateView(LayoutInflater.java:181)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:732)
07-19 16:04:25.720 12380-12380/fr.yougraph.homelesspasseul W/System.err﹕ ... 18 more
07-19 16:04:25.740 12380-12380/fr.yougraph.homelesspasseul D/AndroidRuntime﹕ Shutting down VM
07-19 16:04:25.740 12380-12380/fr.yougraph.homelesspasseul E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: fr.yougraph.homelesspasseul, PID: 12380
java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
at fr.yougraph.homelesspasseul.fragment.MapsFragment.onCreateView(MapsFragment.java:123)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:458)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5944)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1389)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)
第一个例外，由于重复的mapfragment，导致让mView为null，我无法执行findViewById。
我无法看到我错在哪里，之前我使用了一个寻呼机条，并且片段之间的切换效果很好，所以作为地图。
感谢您的帮助
顺便说一句，我尝试了这些问题中给出的解决方案：
Error inflating class fragment: Duplicate id , tag null, or parent id with another fragment
没有工作
答案 0 :(得分：1)
我认为副本来自：在onCreated of MainActivity中你调用setupDrawerContent，它调用selectDrawerItem默认设置你的fragment = mMapfragment，但之前在Oncreate中你已经在这行中创建了另一个MapsFragment：
所以我的建议是尝试将初始化更改为已声明的mMapFragment：