Android的地图在片段 [英] android map in fragment
问题描述
我试图创建具有一个活动和多个片段一个Android应用程序。
每个片段会按观测整个屏幕时，它是在图和用替换交易应当切换到另一个片段
I am trying to create a android app that has one activity and multiple fragments. Each fragment will ocupy the entire screen when it is in view and with a replace transaction it should be switched to another fragment.
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
这是对碎片的容器。
问题是，我想用一个片段是一个GoogleMap的。这是我的code的地图片段：
This is the container for the fragments. The problem is that a fragment that I want to use is a GoogleMap. This is my code for the map fragment:
public class Map extends Fragment{
private final static String TAG = "MAP Fragment";
public GoogleMap googleMap = null;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setUpMapIfNeeded();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.map_fragment, null);
return view;
}
private void setUpMapIfNeeded()
{
if(googleMap == null)
{
googleMap = ((MapFragment) getActivity().getFragmentManager().findFragmentById(R.id.map)).getMap();
if(googleMap != null)
{
GoogleMapOptions options = new GoogleMapOptions();
options.mapType(GoogleMap.MAP_TYPE_NORMAL)
.camera(new CameraPosition(new LatLng(25f, 47f), 13f, 0f, 0f));
}
else
{
Log.d(TAG, "googleMap is null !!!!!!!!!!!!!!!");
}
}
}
}
和它的布局：
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.MapFragment"/>
而在主要活动：
@Override
protected void onCreate(Bundle savedInstanceState)
{
Map test = new Map();
getSupportFragmentManager().beginTransaction()
.add(R.id.content_frame, test)
.commit();
}
我得到一个空指针异常：（我相信它找不到R.id.map）
I get a null pointer exception at: (I belive it cannot find the R.id.map)
googleMap = ((MapFragment) getActivity().getFragmentManager()
.findFragmentById(R.id.map)).getMap();
如果我不使用getActivity（）。它说，它不能从片段转换为MapFragment。
If I don't use "getActivity()." it says that it cannot cast from Fragment to MapFragment.
我需要GoogleMap的在地图上创建标记。
I need "googleMap" for creating markers on the map.
当我做出同样的应用程序，但没有片段（我的主要活动diplays地图，我没有其他碎片）everithing工作正常。
When I make the same application but without fragments (my main activity diplays the map and i don't have other fragments) everithing works fine.
我发现这个类似的主题：<一href=\"http://stackoverflow.com/questions/14458398/google-maps-api-v2-custom-mapfragment-simplefragment\">Google利用地图中的片段地图API V2定制MapFragment + SimpleFragment 和错误。
但是，如果我延长FragmentActivity或SupportMapFragment我不能与其他使用事务替换片段。
I have found this similar topics: Google Maps API v2 Custom MapFragment + SimpleFragment and error using maps in fragment . But if I extend FragmentActivity or SupportMapFragment I cannot replace the fragment with another using transactions.
结论：我想，当一个动作发生（点击或东西）我只需要更换的片段（fragments）是这样的：
Conclusion: I would like that when an action occurs (click or something) I only have to replace the fragmens like this:
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.fragment_container, newFragment);
我是什么做错了吗？或者我应该采取不同的解决问题的方法？
What am I doing wrong? Or should I take a different approach to the problem?
（P.S。我realtively新至Android）
(P.S. I am realtively new to android)
推荐答案
的问题是，我是想在显示之前改变地图元素 setUpMapIfNeeded（）是叫的onCreate（）（视图充气仅在 onCreateView（））。
The problem is that I was trying to change the map element before it was displayed setUpMapIfNeeded() is called in onCreate() (the view is inflated only in onCreateView()).
如果我移动呼叫 setUpMapIfNeeded（） onResume（）一切正常，因为这样的观点进行膨胀，它可以使用地图并修改它。
If I move the call setUpMapIfNeeded() in onResume() everything works because then the view is inflated and it can use the map and modify it.
这篇关于Android的地图在片段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！
