Question

我使用Firebase作为我的应用的后端。但是我无法将Firebase中的PolylineOptions序列化为PolylineOptions类型。如果我尝试使用 dataSnapshot.getValue（PolylineOptions.class）; 将其转换回来，则会出现以下错误消息：

com.firebase.client.FirebaseException: Failed to bounce to type
....  
Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: 
Unrecognized field "width" (class com.google.android.gms.maps.model.PolylineOptions), not marked as ignorable (one known property: "points"])
....
at com.fasterxml.jackson.databind.DeserializationContext.reportUnknownProperty(DeserializationContext.java:555)

我该如何解决这个问题？

以下是演示此问题的代码：

import android.location.Location;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import com.firebase.client.Query;
import com.google.android.gms.maps.model.PolylineOptions;
import com.google.android.gms.maps.model.LatLng;
import com.firebase.client.DataSnapshot;
import com.firebase.client.Firebase;
import com.firebase.client.FirebaseError;
import com.firebase.client.ValueEventListener;


public class MainActivity extends AppCompatActivity{

    PolylineOptions mPolylineOptions;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mPolylineOptions = new PolylineOptions();

        Location targetLocation = new Location("name");
        targetLocation.setLatitude(1.0d);
        targetLocation.setLongitude(2.0d);

        mPolylineOptions.add(new LatLng(targetLocation.getLatitude(), targetLocation.getLongitude()));
        mPolylineOptions.color(ContextCompat.getColor(this, R.color.colorPrimary));

        Firebase.setAndroidContext(this);
        Firebase ref = new Firebase("https://xxxxxxx");
        Firebase testRef = ref.child("test");

        final Query queryRef = testRef.orderByKey();
        queryRef.addValueEventListener(new ValueEventListener() {

            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                Log.d("Test", "data change");
                PolylineOptions activity1 = dataSnapshot.getValue(PolylineOptions.class);
            }

            @Override
            public void onCancelled(FirebaseError firebaseError) {
                System.out.println("The read failed: " + firebaseError.getMessage());
            }
        });
        testRef.setValue(mPolylineOptions);
    }
}

以下是Firebase的JSON：

{
  "test" : {
    "clickable" : false,
    "color" : -12627531,
    "geodesic" : false,
    "points" : [ {
      "latitude" : 50.68468468468468,
      "longitude" : 8.190167190445726
    } ],
    "visible" : true,
    "width" : 10.0,
    "zindex" : 0.0
  }
}

Answer 1

阅读JSON所需的最低类别是：

public static class LatLon {
    public double latitude;
    public double longitude;
}
public static class Test {
    public boolean clickable;
    public long color;
    public boolean geodesic;
    public LatLon[] points;
    public boolean visible;
    public double width;
    public double zindex;
}

我不一定称这些是最佳实践，因为它们更像是C struct而不是类。为了使它们更清洁：

如果private

public

为每个字段添加一个getter方法（getLatitude() getLongitude()和class LatLon

Answer 2

我编写了一个liitle位，这是我的功能模型：

public class PolylineOptions {
    public boolean clickable;
    public long color;
    public boolean geodesic;
    public LatLng[] points = new LatLng[1];;
    public boolean visible;
    public double width;
    public double zindex;

    public PolylineOptions(){

    }

    public void add(LatLng point){
        points[0] = point;
    }
}


public class LatLng {
    public double latitude;
    public double longitude;

    public LatLng(double latitude, double longitude) {
        this.latitude = latitude;
        this.longitude = longitude;
    }

    public LatLng(){

    }
}

但我经常会收到类似的恐怖信息：

Error:(32, 32) error: incompatible types: app.firebasetest.PolylineOptions cannot be converted to com.google.android.gms.maps.model.PolylineOptions

就像：

GoogleMaps mGoogleMap.addPolyline(mPolylineOptions);

我在Firebase中不需要GoogleMaps对象，因此我也不需要为该类型编写模型。我如何说服我的应用程序也承担我的模型？

Firebase序列化PolylineOptions

2 个答案: