背景
我有一个较大的应用程序，其中使用新的 Google Maps API 时遇到了几个问题。我试图在另一个问题中描述它，但由于似乎太复杂了，我决定开始一个尽可能简单的新项目，并尝试重现问题。所以这就是它。
情况
我正在使用Fragments并想要将MapView放置在其中。我不想使用MapFragment。我准备的示例项目可能不太漂亮，但我尽力使其尽可能简单，并且必须包含一些元素（再次简化）来自原始应用程序。我有一个Activity和我的自定义Fragment，其中包含以编程方式添加的MapView。 Map包含一些点/Markers。单击Marker会显示InfoWindow，单击InfoWindow会导致下一个Fragment被显示（使用replace()函数）。
问题
我有两个问题：
当显示带有
Markers的Map时，屏幕旋转会导致Class not found when unmarshalling错误，并显示我的自定义MyMapPoint类 - 我不知道为什么以及它是什么意思。我单击
Marker，然后单击InfoWindow。之后，我按下硬件返回按钮。现在我可以看到Map，但没有Markers并且位于0,0点的中心。
代码
MainActivity
public class MainActivity extends FragmentActivity {
private ArrayList<MyMapPoint> mPoints = new ArrayList<MyMapPoint>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
mPoints.add(new MyMapPoint(1, new LatLng(20, 10),
"test point", "description", null));
mPoints.add(new MyMapPoint(2, new LatLng(10, 20),
"test point 2", "second description", null));
Fragment fragment = MyMapFragment.newInstance(mPoints);
getSupportFragmentManager().beginTransaction()
.add(R.id.contentPane, fragment).commit();
}
}
}
主活动界面.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/contentPane"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
地图片段.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" >
<com.google.android.gms.maps.MapView
xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
我的地图片段
public class MyMapFragment extends Fragment implements
OnInfoWindowClickListener {
public static final String KEY_POINTS = "points";
private MapView mMapView;
private GoogleMap mMap;
private HashMap<MyMapPoint, Marker> mPoints =
new HashMap<MyMapPoint, Marker>();
public static MyMapFragment newInstance(ArrayList<MyMapPoint> points) {
MyMapFragment fragment = new MyMapFragment();
Bundle args = new Bundle();
args.putParcelableArrayList(KEY_POINTS, points);
fragment.setArguments(args);
return fragment;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mMapView.onSaveInstanceState(outState);
MyMapPoint[] points = mPoints.keySet().toArray(
new MyMapPoint[mPoints.size()]);
outState.putParcelableArray(KEY_POINTS, points);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState == null) {
Bundle extras = getArguments();
if ((extras != null) && extras.containsKey(KEY_POINTS)) {
for (Parcelable pointP : extras.getParcelableArrayList(KEY_POINTS)) {
mPoints.put((MyMapPoint) pointP, null);
}
}
} else {
MyMapPoint[] points = (MyMapPoint[]) savedInstanceState
.getParcelableArray(KEY_POINTS);
for (MyMapPoint point : points) {
mPoints.put(point, null);
}
}
}
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View layout = inflater.inflate(R.layout.map_fragment, container, false);
mMapView = (MapView) layout.findViewById(R.id.map);
return layout;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mMapView.onCreate(savedInstanceState);
setUpMapIfNeeded();
addMapPoints();
}
@Override
public void onPause() {
mMapView.onPause();
super.onPause();
}
@Override
public void onResume() {
super.onResume();
setUpMapIfNeeded();
mMapView.onResume();
}
@Override
public void onDestroy() {
mMapView.onDestroy();
super.onDestroy();
}
public void onLowMemory() {
super.onLowMemory();
mMapView.onLowMemory();
};
private void setUpMapIfNeeded() {
if (mMap == null) {
mMap = ((MapView) getView().findViewById(R.id.map)).getMap();
if (mMap != null) {
setUpMap();
}
}
}
private void setUpMap() {
mMap.setOnInfoWindowClickListener(this);
addMapPoints();
}
private void addMapPoints() {
if (mMap != null) {
HashMap<MyMapPoint, Marker> toAdd =
new HashMap<MyMapPoint, Marker>();
for (Entry<MyMapPoint, Marker> entry : mPoints.entrySet()) {
Marker marker = entry.getValue();
if (marker == null) {
MyMapPoint point = entry.getKey();
marker = mMap.addMarker(point.getMarkerOptions());
toAdd.put(point, marker);
}
}
mPoints.putAll(toAdd);
}
}
@Override
public void onInfoWindowClick(Marker marker) {
Fragment fragment = DetailsFragment.newInstance();
getActivity().getSupportFragmentManager().beginTransaction()
.replace(R.id.contentPane, fragment)
.addToBackStack(null).commit();
}
public static class MyMapPoint implements Parcelable {
private static final int CONTENTS_DESCR = 1;
public int objectId;
public LatLng latLng;
public String title;
public String snippet;
public MyMapPoint(int oId, LatLng point,
String infoTitle, String infoSnippet, String infoImageUrl) {
objectId = oId;
latLng = point;
title = infoTitle;
snippet = infoSnippet;
}
public MyMapPoint(Parcel in) {
objectId = in.readInt();
latLng = in.readParcelable(LatLng.class.getClassLoader());
title = in.readString();
snippet = in.readString();
}
public MarkerOptions getMarkerOptions() {
return new MarkerOptions().position(latLng)
.title(title).snippet(snippet);
}
@Override
public int describeContents() {
return CONTENTS_DESCR;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeInt(objectId);
dest.writeParcelable(latLng, 0);
dest.writeString(title);
dest.writeString(snippet);
}
public static final Parcelable.Creator<MyMapPoint> CREATOR =
new Parcelable.Creator<MyMapPoint>() {
public MyMapPoint createFromParcel(Parcel in) {
return new MyMapPoint(in);
}
public MyMapPoint[] newArray(int size) {
return new MyMapPoint[size];
}
};
}
}
AndroidManifest.xml文件中即可。
编辑
我设法使示例更简单，并更新了上面的代码。