空对象引用上的SupportMapFragment.getMap() [英] SupportMapFragment.getMap() on a null object reference
问题描述
在尝试了几乎所有内容之后,如果不提取空对象引用,我似乎无法获得map。我试图将google mapfragment扩展为一个片段,但是每次这样做,我总是保留一个getmap空对象。
这是我的代码
我现在迫切需要任何帮助,我已经尝试了几乎所有内容。
错误
java.lang.NullPointerException:尝试调用虚拟方法'com.google。空对象上的android.gms.maps.GoogleMap com.google.android.gms.maps.SupportMapFragment.getMap()'在com.gnumbu.errolgreen.importedapplication.ViewMapFragment.onViewCreated(ViewMapFragment.java:122 )
在android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:971)
在android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1136)
在android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
在android.support.v4.app.FragmentManager Impl.execPendingActions(FragmentManager.java:1499)
在android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:488)
在android.support.v4.app.FragmentPagerAdapter.finishUpdate( FragmentPagerAdapter.java:141)android.support.v4.view.ViewPager.populate(ViewPager.java:1073)
android.support.v4.view.ViewPager.populate(ViewPager.java: 919)android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
android.view.View.measure(View.java:17430)
android .view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
在android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
在android.view.View.measure(View.java:17430 )android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)中的
android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(Acti onBarOverlayLayout.java:453)android.view.View.measure(View.java:17430)
android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
.widget.FrameLayout.onMeasure(FrameLayout.java:430)
在android.view.View.measure(View.java:17430)
在android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463 )
在android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
在android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
在android.widget.LinearLayout。 onMeasure(LinearLayout.java:613)
在android.view.View.measure(View.java:17430)
在android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
在android.widget.FrameLayout.onMeasure(FrameLayout.java:430)上
在com.android.internal.policy.impl.PhoneWindow $ DecorView.onMeasure(PhoneWindo w.java:2560)android.view.View.measure(View.java:17430)
android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001)
.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166)
在android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372)
在android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054 )
在android.view.ViewRootImpl $ TraversalRunnable.run(ViewRootImpl.java:5779)
在android.view.Choreographer $ CallbackRecord.run(Choreographer.java:767)
在android。 view.Choreographer.doCallbacks(Choreographer.java:580)
在android.view.Choreographer.doFrame(Choreographer.java:550)
在android.view.Choreographer $ FrameDisplayEventReceiver.run(Choreographer.java: 753)android.os.Handler.handleCallback(Handler.java:739)
android.os.Handler.dispatchMessage(Handler.ja) va:95)android.os.Looper.loop(Looper.java:135)
android.app.ActivityThread.main(ActivityThread.java:5221)
java.lang .reflect.Method.invoke(本机方法)java.lang.reflect.Method.invoke(Method.java:372)
在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run( ZygoteInit.java:899)
在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
片段java类
public View onCreateView(LayoutInflater inflater,ViewGroup container,
Bundle savedInstanceState){
if(container == null){
返回null;
}
view =(RelativeLayout)inflater.inflate(R.layout.fragmentmenu_layout,container,false);
//传递经纬度的经编码值&经度。请根据您的需要进行更改。这只是用来在地图上放置标记
纬度= 26.78;
经度= 72.56;
; //用于设置MapFragment
返回视图;
}
/ *****可以设置地图***** /
public static void setUpMapIfNeeded(){
//执行空值检查以确认我们尚未实例化地图。
if(mMap == null){
//尝试从SupportMapFragment获取地图。
mMap =((SupportMapFragment)SectionsPagerAdapter.fragmentManager
.findFragmentById(R.id.mapView))。getMap();
//检查我们是否成功获取了地图。
if(mMap!= null)
setUpMap();
}
}
/ **
*这是我们可以添加标记或行,添加侦听器或移动
*摄像机的地方。
*< p>
*仅当我们确定{@link #mMap}
*不为null时,才应调用此方法。
* /
private static void setUpMap(){
//用于显示移至我的移动按钮
mMap.setMyLocationEnabled(true);
//用于在地图上的某个点放置标记
mMap.addMarker(new MarkerOptions()。position(new LatLng(latitude,longitude))。title( My Home)。snippet( 家庭地址));
//用于自动缩放到放置的PIN位置
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude,
经度),12.0f));
}
@Override
public void onViewCreated(View view,Bundle savedInstanceState){
// TODO自动生成的方法存根
如果(mMap!= null)
setUpMap();
if(mMap == null){
//尝试从SupportMapFragment获取地图。
mMap =((SupportMapFragment)MainActivity.fragmentManager
.findFragmentById(R.id.mapView))。getMap(); //不推荐使用getMap
//检查是否成功获取了地图。
if(mMap!= null)
setUpMap();
getAllFeaturedItems();
captureMapScreen();
}
}
@Override
public void onStart(){
super.onStart();
}
@Override
public void onResume(){
super.onResume();
setUpMapIfNeeded();
}
@Override
public void onPause(){
super.onPause();
}
@Override
public void onStop(){
super.onStop();
}
@Override
public void onLowMemory(){
super.onLowMemory();
}
/ ****必须从FragmentManager
****中删除mapfragment的ID,否则,如果下次再次传递相同的ID,则
****应用程序将崩溃**** /
@Override
public void onDestroyView(){
super.onDestroyView();
if(mMap!= null){
MainActivity.fragmentManager.beginTransaction()
.remove(MainActivity.fragmentManager.findFragmentById(R.id.mapView))。commit();
mMap = null;
}
}
@Override
public void onDestroy(){
super.onDestroy();
}
fragmentmenu_layout.xml
<?xml version = 1.0 encoding = utf-8?>
< RelativeLayout xmlns:android = http://schemas.android.com/apk/res/android
android:orientation = vertical android:layout_width = match_parent
android:layout_height = match_parent
android:translationZ = 5dp
>
< ListView
android:layout_width = match_parent
android:layout_height = match_parent
android:id = @ + id / listViewMenu
android:layout_gravity = center_horizontal
android:dividerHeight = 1sp
android:translationZ = 5dp
android:divider = @ color / background_default
android:background = @ color / background_white
android:clickable = true
android:layout_alignParentLeft = true
android:layout_alignParentStart = true
android:layout_below = @ + id / screenShotMapView />
< ImageView
android:layout_width = wrap_content
android:layout_height = wrap_content
android:id = @ + id / screenShotMapView
android:layout_alignParentTop = true
android:maxWidth = 50dp
android:layout_alignParentLeft = true
android:layout_alignParentStart = true
android:layout_alignParentRight = true
android:layout_alignParentEnd = true
android:adjustViewBounds = true
android:translationZ = 5dp
/>
<片段
class = com.google.android.gms.maps.MapFragment
android:layout_width = wrap_content
android:layout_height = wrap_content
android:id = @ + id / mapView
android:layout_alignParentTop = true
android:layout_alignParentRight = true
android:layout_alignParentEnd = true
android:layout_alignParentLeft = true
android:layout_alignParentStart = true
android:adjustViewBounds = true
android:longClickable = false
android:visibility = visible
android:maxHeight = 50dp
android:maxWidth = 50dp
/>
< / RelativeLayout>
MainActivity.java
公共静态FragmentManagerfragmentManager;
@Override
protected void onCreate(Bundle savedInstanceState){
// setTheme(R.style.ActionBarTheme);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化FragmentManager的对象。在这里,我传递了getSupportFragmentManager()。如果您为Android 3.0或更高版本进行编码,则可以传递getFragmentManager()。
//最终ActionBar actionBar = getSupportActionBar();
buildGoogleApiClient();
// actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mImageBitmap = null;
//创建将为每个节/页返回片段的适配器
mSectionsPagerAdapter = new SectionsPagerAdapter(
this.getBaseContext(),getSupportFragmentManager());
fragmentManager = getSupportFragmentManager();
//使用section适配器设置ViewPager。
mViewPager =(ViewPager)findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){
@Override
public void onPageSelected(int position){
// actionBar.setSelectedNavigationItem(position);
}
});
//对于应用程序中的每个部分,在操作栏中添加一个标签。
/ *
for(int i = 0; i< mSectionsPagerAdapter.getCount(); i ++){
//创建一个选项卡,其中文本与$ b $定义的页面标题相对应b //适配器。还指定此Activity对象,该对象实现
// TabListener接口,作为选择
//此选项卡时的回调(侦听器)。
if(i == 0){
actionBar.addTab(
actionBar.newTab()
.setIcon(R.drawable.ic_action_view_as_list)
// .setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this)
);
}
if(i == 1){
actionBar.addTab(
actionBar.newTab()
.setIcon(R.drawable.ic_action_web_site_dark )
// .setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this)
);
}
}
* /
mAlbumStorageDirFactory = new BaseAlbumDirFactory();
Intent intent = new Intent(this,SplashScreen.class);
startActivity(intent);
}
不太确定为什么我对此不满意,但是我已经解决了这个问题。
此行
mMap =((SupportMapFragment)MainActivity.fragmentManager
.findFragmentById(R.id.mapView))。getMap();
需要更改为
mMap =((SupportMapFragment)getChildFragmentManager()
.findFragmentById(R.id.mapView))。getMap();
After trying just about everything, I cannot seem to getmap without pulling a null object reference. I am trying to inflate a google mapfragment into a fragment, however each time I do so I always keep a getmap null object .
Here is my code
I'm desperate for any help at this point, I've tried just about everything.
Error
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.gnumbu.errolgreen.importedapplication.ViewMapFragment.onViewCreated(ViewMapFragment.java:122)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:971)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1136)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1499)
at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:488)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1073)
at android.support.v4.view.ViewPager.populate(ViewPager.java:919)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1441)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.support.v7.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:453)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17430)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5463)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:430)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2560)
at android.view.View.measure(View.java:17430)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2001)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1166)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1372)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1054)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5779)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Fragment java class
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
if (container == null) {
return null;
}
view = (RelativeLayout) inflater.inflate(R.layout.fragmentmenu_layout, container, false);
// Passing harcoded values for latitude & longitude. Please change as per your need. This is just used to drop a Marker on the Map
latitude = 26.78;
longitude = 72.56;
; // For setting up the MapFragment
return view;
}
/***** Sets up the map if it is possible to do so *****/
public static void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) SectionsPagerAdapter.fragmentManager
.findFragmentById(R.id.mapView)).getMap();
// Check if we were successful in obtaining the map.
if (mMap != null)
setUpMap();
}
}
/**
* This is where we can add markers or lines, add listeners or move the
* camera.
* <p>
* This should only be called once and when we are sure that {@link #mMap}
* is not null.
*/
private static void setUpMap() {
// For showing a move to my loction button
mMap.setMyLocationEnabled(true);
// For dropping a marker at a point on the Map
mMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).title("My Home").snippet("Home Address"));
// For zooming automatically to the Dropped PIN Location
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude,
longitude), 12.0f));
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
// TODO Auto-generated method stub
if (mMap != null)
setUpMap();
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) MainActivity.fragmentManager
.findFragmentById(R.id.mapView)).getMap(); // getMap is deprecated
// Check if we were successful in obtaining the map.
if (mMap != null)
setUpMap();
getAllFeaturedItems();
captureMapScreen();
}
}
@Override
public void onStart() {
super.onStart();
}
@Override
public void onResume() {
super.onResume();
setUpMapIfNeeded();
}
@Override
public void onPause() {
super.onPause();
}
@Override
public void onStop() {
super.onStop();
}
@Override
public void onLowMemory() {
super.onLowMemory();
}
/**** The mapfragment's id must be removed from the FragmentManager
**** or else if the same it is passed on the next time then
**** app will crash ****/
@Override
public void onDestroyView() {
super.onDestroyView();
if (mMap != null) {
MainActivity.fragmentManager.beginTransaction()
.remove(MainActivity.fragmentManager.findFragmentById(R.id.mapView)).commit();
mMap = null;
}
}
@Override
public void onDestroy() {
super.onDestroy();
}
fragmentmenu_layout.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:translationZ="5dp"
>
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/listViewMenu"
android:layout_gravity="center_horizontal"
android:dividerHeight="1sp"
android:translationZ="5dp"
android:divider="@color/background_default"
android:background="@color/background_white"
android:clickable="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_below="@+id/screenShotMapView" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/screenShotMapView"
android:layout_alignParentTop="true"
android:maxWidth="50dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:adjustViewBounds="true"
android:translationZ="5dp"
/>
<fragment
class="com.google.android.gms.maps.MapFragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/mapView"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:adjustViewBounds="true"
android:longClickable="false"
android:visibility="visible"
android:maxHeight="50dp"
android:maxWidth="50dp"
/>
</RelativeLayout>
MainActivity.java
public static FragmentManager fragmentManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
// setTheme(R.style.ActionBarTheme);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// initialising the object of the FragmentManager. Here I'm passing getSupportFragmentManager(). You can pass getFragmentManager() if you are coding for Android 3.0 or above.
// final ActionBar actionBar = getSupportActionBar();
buildGoogleApiClient();
// actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mImageBitmap = null;
// Create the adapter that will return a fragment for each section/page
mSectionsPagerAdapter = new SectionsPagerAdapter(
this.getBaseContext(), getSupportFragmentManager());
fragmentManager = getSupportFragmentManager();
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
// actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
/*
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
// Create a tab with text corresponding to the page title defined by
// the adapter. Also specify this Activity object, which implements
// the TabListener interface, as the callback (listener) for when
// this tab is selected.
if (i == 0) {
actionBar.addTab(
actionBar.newTab()
.setIcon(R.drawable.ic_action_view_as_list)
// .setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this)
);
}
if (i == 1) {
actionBar.addTab(
actionBar.newTab()
.setIcon(R.drawable.ic_action_web_site_dark)
// .setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this)
);
}
}
*/
mAlbumStorageDirFactory = new BaseAlbumDirFactory();
Intent intent = new Intent(this, SplashScreen.class);
startActivity(intent);
}
Not too sure why I was downvoted so much on this, However I have solved the issue.
This line
mMap = ((SupportMapFragment) MainActivity.fragmentManager
.findFragmentById(R.id.mapView)).getMap();
needed to be changed to
mMap = ((SupportMapFragment) getChildFragmentManager()
.findFragmentById(R.id.mapView)).getMap();
这篇关于空对象引用上的SupportMapFragment.getMap()的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!