android - Google Firebase 序列化/反序列化

Question

我是 FIrebase 的新手，我有 2 个可能与之相关的问题。第一个是保存我的事件列表时。

//creating event
TVEvent tvEvent = new TVEvent(etTitle.getText().toString());
User host = ResourceManager.getUser();
String date = etDate.getText().toString();
String location = etLocation.getText().toString();
TVSet tvset = ResourceManager.getUser().getTvSets().get(0);
Event ev = new Event(tvEvent, host, date, location, tvset);
ResourceManager.addEvent(ev);
mDatabase.child("events").child(host.getId()).setValue(ResourceManager.getEvents()); //getEvents() returns a list of events

这是我在控制台中得到的

问题是 tvevent 和 tv set 的属性比这些多。当我调试以找出为什么 tvevent 是用它的所有属性创建的时，这有点奇怪。但是现在，我不知道这是否是个问题，因为我无法从数据库中检索 tvset 和 tvevent。当我执行以下操作时，我得到的是 null。

mDatabase.child("events").addListenerForSingleValueEvent(
    new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            System.out.println("Cheking for events");
            //GenericTypeIndicator<List<Event>> t = new GenericTypeIndicator<List<Event>>() {};
            //List<Event> e = dataSnapshot.getValue(t);
            for (DataSnapshot messageSnapshot: dataSnapshot.getChildren()) {
                GenericTypeIndicator<List<Event>> t = new GenericTypeIndicator<List<Event>>() {};
                List<Event> list = messageSnapshot.getValue(t);
                if (list != null) {
                    for (Event ev : list) {
                        System.out.println("Event found");
                        ResourceManager.addEvent(ev);
                    }
                }
            }


        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

我不知道为什么这些值为空，因为我可以看到它们不在 firebase 控制台中。那么问题是什么？

@IgnoreExtraProperties
public class Event {

private TVEvent tvEvent;
private User host;
private Date date;
private String location;
private TVSet tvSet;
private List<User> attending;

public Event(){
}

public Event(TVEvent tvEvent, User host, String date, String location, TVSet tvset){
    this.tvSet = tvset;
    this.tvEvent = tvEvent;
    this.host = host;
    try {
        this.date = new SimpleDateFormat("dd/MM/yyyy").parse(date);
    } catch (ParseException e) {
        e.printStackTrace();
    }

    this.location = location;

    attending = new ArrayList<>();
}

public User getHost() {
    return host;
}

public String getLocation() {
    return location;
}

public TVSet getTVSet() {
    return tvSet;
}

public Date getDate() {
    return date;
}

public TVEvent getTVEvent() {
    return tvEvent;
}

public void addAttending(User user){
    attending.add(user);
}

public List<User> getAttending(){
    return attending;
}
}

由于 TVSet 和 TVEvent 都没有正确反序列化，我将只发布其中一个:

@IgnoreExtraProperties
public class TVSet {

private String title;
private String imageFile;
//private Bitmap picture;

public TVSet(){

}

public TVSet(String title){
    this.title = title;
}

public TVSet(Bitmap picture){
    imageFile = compressImage(picture);
}

public void setTitle(String title){
    this.title = title;
}

public String getTitle() {
    return title;
}

private String compressImage(Bitmap image){
    ByteArrayOutputStream bYtE = new ByteArrayOutputStream();
    image.compress(Bitmap.CompressFormat.PNG, 100, bYtE);
    //image.recycle();
    byte[] byteArray = bYtE.toByteArray();
    String imageFile = Base64.encodeToString(byteArray, Base64.DEFAULT);
    return imageFile;
}


@Exclude
public Bitmap getImage() {
    byte[] decodedString = Base64.decode(imageFile, Base64.DEFAULT);
    Bitmap bitmap = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);
    return bitmap;
}

public String getImageFile(){
    return imageFile;
}
}

抱歉格式错误。感谢您的帮助。

Answer 1

尝试使用

Map<String, String> data= (HashMap<String, String>)dataSnapshot.getValue();

代替

GenericTypeIndicator<List<Event>> t = new GenericTypeIndicator<List<Event>>() {}; List<Event> list = messageSnapshot.getValue(t);