使用标记保存地图状态(谷歌地图)

Question

我想在我正在开发的android应用程序中保存谷歌地图的状态，我设法保存了相机的状态，但包括标记在内的状态没有成功。有什么建议吗？？

我创建了一个保存相机状态的函数和一个尝试保存书签类的方法。但它不起作用。

MapStateManager.java

public class MapStateManager {
private SharedPreferences mapStatePrefs;
private MarkerOptions markerOptions;
private GoogleMap map;
private static final String LATITUD = "latitud";
private static final String LONGITUD = "longitud";
private static final String LATITUD_MARKER = "latitud";
private static final String LONGITUD_MARKER = "longitud";
private static final String ZOOM = "zoom";
private static final String BEARING = "bearing";
private static final String TILT = "tilt";
private static final String MAPTYPE = "maptype";
private static final String PREFS_NAME = "mapCameraState";
 public MapStateManager(Context context, MarkerOptions markerOptions){
    this.markerOptions = markerOptions;
    mapStatePrefs = context.getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);

}
public void saveMapState(GoogleMap map){
    SharedPreferences.Editor editor = mapStatePrefs.edit();
    CameraPosition position = map.getCameraPosition();
    editor.putFloat(LATITUD, (float) position.target.latitude);
    editor.putFloat(LONGITUD, (float) position.target.longitude);
    editor.putFloat(ZOOM,  position.zoom);
    editor.putFloat(TILT, position.tilt);
    editor.putFloat(BEARING,position.bearing);
    editor.putFloat(MAPTYPE, map.getMapType());
    editor.commit();

}
public MarkerOptions saveMarkersState(){
    MarkerOptions marker = markerOptions;
    marker = new MarkerOptions()
            .title("marker")
            .position(new LatLng(marker.getPosition().latitude, marker.getPosition().longitude))
            .icon(BitmapDescriptorFactory.defaultMarker());
    map.addMarker(marker);
    if(marker.getPosition().latitude == 0){
        return null;
    }
    if(marker.getPosition().longitude == 0){
        return null;
    }

    //LatLng position = new LatLng(latitud, longitud);
    SharedPreferences.Editor editor = mapStatePrefs.edit();
    editor.putFloat(LATITUD_MARKER, (float) marker.getPosition().latitude);
    editor.putFloat(LONGITUD_MARKER, (float) marker.getPosition().longitude);

    editor.commit();


    return marker;
}
public CameraPosition saveCameraPosition(){
    double latitud = mapStatePrefs.getFloat(LATITUD, 0);
    if(latitud == 0){
        return null;
    }
    double longitud= mapStatePrefs.getFloat(LONGITUD, 0);
    LatLng target = new LatLng(latitud, longitud);
    float zoom = mapStatePrefs.getFloat(ZOOM, 0);
    float bearing = mapStatePrefs.getFloat(BEARING, 0);
    float tilt = mapStatePrefs.getFloat(TILT, 0);
    CameraPosition position = new CameraPosition(target, zoom, tilt, bearing);


    return position;

}
}

MainActivity.java（重写方法）

@Override
protected void onResume() {
    super.onResume();
    mapFragment.onResume();
   // onSaveInstanceState(state);
    setUpMapIfNeeded();
    MapStateManager mapstateCamera = new MapStateManager(this, markerOptions);
    CameraPosition position = mapstateCamera.saveCameraPosition();
    if(position != null){
        CameraUpdate update = CameraUpdateFactory.newCameraPosition(position);
        mMap.moveCamera(update);
        //mMap.getMyLocation();
    }

    /*if(markerOptions != null){
        mapstateCamera.saveMarkersState();
    }*/
//
}

@Override
protected void onSaveInstanceState(Bundle guardarEstado) {
    super.onSaveInstanceState(guardarEstado);
    String joined = TextUtils.join(", ", markers);
    guardarEstado.putString(STATE_MAP_MARKER, joined);

}
 @Override
protected void onRestoreInstanceState(Bundle recuperarEstado) {
    super.onRestoreInstanceState(recuperarEstado);
    mCurrentScore = recuperarEstado.getString(STATE_MAP_RECOVERY);

}

@Override
protected void onStop() {
    MapStateManager mapState = new MapStateManager(this, markerOptions);
    mapState.saveMapState(mMap);
    //mapState.saveMarkersState();

    super.onStop();
}
@Override
protected void onPause() {
    super.onPause();
    mapFragment.onPause();
}

感谢所有人：）

Answer 1

这个问题过去在SO.上被提出过很多次

处理这种情况的最佳方法是使用共享首选项并在本地存储标记。即使应用程序被关闭，重新打开时标记也会恢复到同一位置。

有关代码，请参阅此堆栈溢出答案。

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