谷歌地图正在返回空指针异常 [英] google maps are returning null pointer exception
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问题描述
当我试图在片段上显示地图时，它返回空指针异常。
我已将所有内容添加到清单中。
我附加了它的XML文件和日志文件的碎片文件
Chatffragment.java
public class ChatFragment extends Fragment {
// Google Map
private GoogleMap googleMap;
public ChatFragment（）{
//必需的空公共构造函数
}
@Override
public void onCreate（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）;
$ b @Override
public View onCreateView（LayoutInflater inflater，ViewGroup容器，
Bundled savedInstanceState）
{
View chatfrag = inflater.inflate（R.layout.chatfragment，container，false）;
try {
//载入地图
initilizeMap（）;
} catch（Exception e）{
e.printStackTrace（）;
}
return chatfrag;
}
/ **
*函数来加载地图。如果map没有创建，它会为你创建它
* * /
private void initilizeMap（）
{
if（googleMap == null）{
SupportMapFragment mapFrag =（SupportMapFragment）getActivity（）。getSupportFragmentManager（）。findFragmentById（R.id.map）;
googleMap = mapFrag.getMap（）;
googleMap.setMyLocationEnabled（true）;
//检查映射是否成功创建
if（googleMap == null）{
Toast.makeText（getActivity（），
）对不起！创建地图，Toast.LENGTH_SHORT）
.show（）;
$ @Override
public void onResume（）{
super.onResume（）;
initilizeMap（）;
}
}
它的XML
<？xml version =1.0encoding = UTF-8 >？;
< RelativeLayout xmlns：android =http://schemas.android.com/apk/res/android
android：layout_width =fill_parent
android：layout_height =fill_parent >
< fragment
android：id =@ + id / map
android：name =com.google.android.gms.maps.SupportMapFragment
android：layout_width =match_parent
android：layout_height =match_parent/>
< / RelativeLayout>
LOGCAT
04-05 09：12：22.075 26987-26987 / com.example.vikrant.safeshelter E / AndroidRuntime：FATAL EXCEPTION：main
进程：com.example.vikrant.safeshelter，PID：26987
java.lang.NullPointerException：试图调用虚拟方法'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap（）' com.example.vikrant.safeshelter.ChatFragment.initilizeMap（ChatFragment.java:55）处的空对象引用
（位于com.example.vikrant.safeshelter.ChatFragment.onResume处的
）（ChatFragment.java:70）
在android.support.v4.app.Fragment.performResume（Fragment.jav a：2020）
at android.support.v4.app.FragmentManagerImpl.moveToState（FragmentManager.java:1107）
at android.support.v4.app.FragmentManagerImpl.moveToState（FragmentManager.java:1252）
at android.support.v4.app.BackStackRecord.run（BackStackRecord.java:738）
at android.support.v4.app.FragmentManagerImpl.execPendingActions（FragmentManager.java:1617）
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions（FragmentManager.java:570）
at android.support.v4.app.FragmentStatePage rAdapter.finishUpdate（FragmentStatePagerAdapter.java:164）
at android.support.v4.view.ViewPager.populate（ViewPager.java:1177）
at android.support.v4.view.ViewPager.setCurrentItemInternal（
at android.support.v4.view.ViewPager.setCurrentItemInternal（ViewPager.java:570）
at android.support.v4.view.ViewPager.setCurrentItem（ViewPager.java：ViewPager.java:608） 551）
at android.support.design.widget.TabLayout $ ViewPagerOnTabSelectedListener.onTabSelected（TabLayout.java:1627）
at android.support .design.widget.TabLayout.selectTab（TabLayout.java:837）
at android.support.design.widget.TabLayout.selectTab（TabLayout.java:809）
at android.support.design.widget .TabLayout $ Tab.select（TabLayout.java:1077）
at android.support.design.widget.TabLayout $ 1.onClick（TabLayout.java:643）
at android.view.View.performClick（ View.java:4759）
at android.view.View $ PerformClick.run（View.java:19770）
at android.os.Handler.handleCallback（Handler.java:739）
在android.os.Handler.dispatchMessage（Handler.java:95）
在android.os.Looper.loop（Looper.java:135）
在android.app.ActivityThread.main（ActivityThread.java ：5234）
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:909）
at com.android.internal.os.ZygoteInit.main（ZygoteInit.java:704）
一行55和70是
googleMap = mapFrag.getMap（）;
initilizeMap（）;
解决方案
b
$ b
public class ChatFragment extends Fragment implements OnMapReadyCallback {
$ b $ private void initilizeMap（）{
// SupportMapFragment mapFragment = （SupportMapFragment）fragmentManager.findFragmentById（R.id.map）;
SupportMapFragment mapFrag =（SupportMapFragment）getChildFragmentManager（）。findFragmentById（R.id.map）;
mapFrag.getMapAsync（this）;
}
@Override
public void onMapReady（最终GoogleMap地图）{
googleMap = map;
//做其他事..........
}
}
$ b $编辑
$ b $ pre $ SupportMapFragment mapFrag =（SupportMapFragment）getChildFragmentManager（）。findFragmentById（R .id.map）;
检查编辑代码，使用ChildFragmentManager。
when I am trying to show the maps on my fragment it is returning null pointer exception. I have added everything to the manifest each and every permission. I am attaching the fragment file its XML file and the log cat
Chatffragment.java
public class ChatFragment extends Fragment{
// Google Map
private GoogleMap googleMap;
public ChatFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
{
View chatfrag = inflater.inflate(R.layout.chatfragment, container, false);
try {
// Loading map
initilizeMap();
} catch (Exception e) {
e.printStackTrace();
}
return chatfrag;
}
/**
* function to load map. If map is not created it will create it for you
* */
private void initilizeMap()
{
if (googleMap == null) {
SupportMapFragment mapFrag = (SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.map);
googleMap = mapFrag.getMap();
googleMap.setMyLocationEnabled(true);
// check if map is created successfully or not
if (googleMap == null) {
Toast.makeText(getActivity(),
"Sorry! unable to create maps", Toast.LENGTH_SHORT)
.show();
}
}
}
@Override
public void onResume() {
super.onResume();
initilizeMap();
}
}
Its XML
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<fragment
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
LOGCAT
04-05 09:12:22.075 26987-26987/com.example.vikrant.safeshelter E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.vikrant.safeshelter, PID: 26987
java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()' on a null object reference
at com.example.vikrant.safeshelter.ChatFragment.initilizeMap(ChatFragment.java:55)
at com.example.vikrant.safeshelter.ChatFragment.onResume(ChatFragment.java:70)
at android.support.v4.app.Fragment.performResume(Fragment.java:2020)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1107)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1252)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570)
at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:164)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1177)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:608)
at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:570)
at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:551)
at android.support.design.widget.TabLayout$ViewPagerOnTabSelectedListener.onTabSelected(TabLayout.java:1627)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:837)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:809)
at android.support.design.widget.TabLayout$Tab.select(TabLayout.java:1077)
at android.support.design.widget.TabLayout$1.onClick(TabLayout.java:643)
at android.view.View.performClick(View.java:4759)
at android.view.View$PerformClick.run(View.java:19770)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5234)
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:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
line 55 and 70 are googleMap = mapFrag.getMap(); initilizeMap();
解决方案
You have to wait until map getting loaded....
public class ChatFragment extends Fragment implements OnMapReadyCallback {
private void initilizeMap() {
//SupportMapFragment mapFragment = (SupportMapFragment) fragmentManager.findFragmentById(R.id.map);
SupportMapFragment mapFrag = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
mapFrag.getMapAsync(this);
}
@Override
public void onMapReady(final GoogleMap map) {
googleMap = map;
//Do other stuff..........
}
}
Edit
SupportMapFragment mapFrag = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
Check the edit code, use ChildFragmentManager.
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