我正在尝试创建一个翻转 View ，其中包含一侧的 Google map 和一侧的 Recyclerview。 我在尝试调用 Map fragment 时遇到错误。它给出空指针，而 map 必须在初始化时加载。
文件 1:fragment_left.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@android:color/transparent">
<fragment
android:id="@+id/map_fragment"
android:layout_below="@+id/header"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_above="@+id/footer"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</LinearLayout>
文件 2:fragment_right.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/transparent"
android:orientation="vertical" >
<android.support.v7.widget.RecyclerView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/header"
android:background="@mipmap/back"
android:layout_above="@+id/footer"/>
</LinearLayout>
文件 3 : flipscreen.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".flipscreen" >
<RelativeLayout
android:id="@+id/header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:background="@mipmap/gradiant"
android:layout_alignParentTop="true"
android:padding="6dp">
<TextView
android:id="@+id/activity_registration_txtTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textSize="16sp"
android:textStyle="bold"
android:text="@string/events"/>
<ImageView
android:id="@+id/listOfEvent"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_alignParentRight="true"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="@mipmap/menu"/>
</RelativeLayout>
<FrameLayout
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_below="@+id/header"
android:layout_above="@+id/footer"
android:layout_height="wrap_content"
android:layout_centerInParent="true" >
</FrameLayout>
</RelativeLayout>
Java 文件 文件 1:flipscreen.java:
public class flipscreen extends FragmentActivity {
private boolean showingBack;
private FragmentLeft left = new FragmentLeft();
private FragmentRight right = new FragmentRight();
private Context context;
private Handler handler;
private FlipAnimation flipAnimation;
private FlipAnimation backFlip;
private GoogleMap map;
private FragmentManager mFragmrg;
List<Event> lsEvent=new ArrayList<Event>();
private double latitude = 0;
private double longitude = 0;
FrameLayout mapLayout;
ImageView flipView;
ImageButton btnAddEvent;
String strUserId;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.flipscreen);
context = this;
handler = new Handler(getMainLooper());
mapLayout = (FrameLayout)findViewById(R.id.fragment_container);
getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, right, "fragmentRight").commit();
getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, left, "fragmentLeft").commit();
flipView=(ImageView) findViewById(R.id.listOfEvent);
btnAddEvent=(ImageButton)findViewById(R.id.btnAddEvent);
btnAddEvent.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(!(strUserId.equals(""))){
startActivity(new Intent(flipscreen.this,AddEventActivity.class));
// finish();
}else{
startActivity(new Intent(flipscreen.this,LoginActivity.class));
}
}
});
flipView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
flipAnimation = new FlipAnimation(left.getView(), right.getView());
backFlip = new FlipAnimation(left.getView(), right.getView());
handler.removeCallbacks(rotate);
handler.postDelayed(rotate, 100);
}
});
}
private Runnable rotate = new Runnable() {
@Override
public void run() {
if (!showingBack) {
left.getView().startAnimation(flipAnimation);
right.getView().startAnimation(flipAnimation);
// Toast.makeText(context, "flip", Toast.LENGTH_LONG).show();
flipView.setImageResource(R.mipmap.nav_map);
showingBack = true;
} else {
showingBack = false;
backFlip.reverse();
// Toast.makeText(context, "backflip", Toast.LENGTH_LONG).show();
left.getView().startAnimation(backFlip);
right.getView().startAnimation(backFlip);
flipView.setImageResource(R.mipmap.menu);
}
}
};
}
文件 2:fragmentLeft.java:
public class FragmentLeft extends Fragment {
private GoogleMap map;
private FragmentManager mFragmrg;
List<Event> lsEvent=new ArrayList<Event>();
private double latitude = 0;
private double longitude = 0;
private SupportMapFragment mMapFragment;
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View flipMap =inflater.inflate(R.layout.fragment_left, container,false);
SupportMapFragment mapFragment = (SupportMapFragment) getFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(GoogleMap googleMap) {
map = googleMap;
// // Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(latitude, longitude);
map.clear();
CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(new LatLng(latitude, longitude), 8);
map.animateCamera(cameraUpdate);
System.out.println("Latitude "+latitude+ " \n Longitude "+longitude);
}
});
return flipMap;
}
}
文件 3:FragmentRight.java:
public class FragmentRight extends Fragment {
private static final String TAG ="NearByActivityList" ;
RecyclerView recyclerView;
List<Event> lsEvent=new ArrayList<Event>();
protected GoogleApiClient mGoogleApiClient;
protected Location mLastLocation;
ImageView listOfEvent;
double latitude = 0;
double longitude = 0;
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View fillData =inflater.inflate(R.layout.fragment_right, container,false);
recyclerView = (RecyclerView) fillData.findViewById(R.id.list);
GridLayoutManager manager = new GridLayoutManager(getActivity(), 3);
manager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return (3 - position % 3);
}
});
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
return fillData;
}
}
我的问题是在 fragmentLeft.java 中它变得空了
SupportMapFragment mapFragment = (SupportMapFragment) getFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(new OnMapReadyCallback() {
最佳答案
我已经检查了你的代码，我认为错误是 R.id.map，你没有，@+id/map in xml 你有 @+id/map_fragment:
SupportMapFragment mapFragment = (SupportMapFragment) getFragmentManager().findFragmentById(R.id.map_fragment)
mapFragment.getMapAsync(new OnMapReadyCallback() {
关于java - 谷歌地图未在自定义 Flipview 中初始化，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38102106/