Android firebase - 为什么点击星标总是删除一个子值？
这是FreeboardPost.java
public class FreeboardPost
{
public String imageUrl;
public String uid;
public String author;
public String title;
public String body;
public int starCount = 0;
public Map<String, Boolean> stars = new HashMap<>();
public FreeboardPost()
{
}
public FreeboardPost(String uid, String author, String title, String body, String imageUrl)
{
this.imageUrl = imageUrl;
this.uid = uid;
this.author = author;
this.title = title;
this.body = body;
}
@Exclude
public Map<String, Object> toMap()
{
HashMap<String, Object> result = new HashMap<>();
result.put("image", imageUrl);
result.put("uid", uid);
result.put("author", author);
result.put("title", title);
result.put("body", body);
result.put("starCount", starCount);
result.put("stars", stars);
return result;
}
}
这是FreeboardPostViewHolder.java
public class FreeboardPostViewHolder extends RecyclerView.ViewHolder
{
public TextView freeboardtitleView;
public TextView freeboardauthorView;
public ImageView freeboardstarView;
public TextView freeboardnumStarsView;
public TextView freeboardbodyView;
public CircleImageView freeboardprofileView;
public FreeboardPostViewHolder(View itemView)
{
super(itemView);
freeboardtitleView = (TextView) itemView.findViewById(R.id.freeboard_post_title);
freeboardauthorView = (TextView) itemView.findViewById(R.id.freeboard_post_author);
freeboardstarView = (ImageView)itemView.findViewById(R.id.freeboard_star);
freeboardnumStarsView = (TextView)itemView.findViewById(R.id.freeboard_post_num_stars);
freeboardbodyView = (TextView)itemView.findViewById(R.id.freeboard_post_body);
freeboardprofileView = (CircleImageView)itemView.findViewById(R.id.freeboard_post_author_photo);
}
public void bindToPost(FreeboardPost freeboardpost, View.OnClickListener starClickListener)
{
freeboardtitleView.setText(freeboardpost.title);
freeboardauthorView.setText(freeboardpost.author);
freeboardnumStarsView.setText(String.valueOf(freeboardpost.starCount));
freeboardbodyView.setText(freeboardpost.body);
freeboardstarView.setOnClickListener(starClickListener);
}
}
这是FreeboardPostListFragment.java
public abstract class FreeboardPostListFragment extends Fragment
{
private static final String TAG = "FreeBoardPostListFragment";
private DatabaseReference mDatabase;
private FirebaseRecyclerAdapter<FreeboardPost, FreeboardPostViewHolder> mAdapter;
private RecyclerView mRecycler;
private LinearLayoutManager mManager;
private DatabaseReference mPostReference;
private ValueEventListener mPostListener;
private String image;
public FreeboardPostListFragment()
{
}
@Override
public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
super.onCreateView(inflater, container, savedInstanceState);
View rootView = inflater.inflate(R.layout.freeboard_fragment_all_posts, container, false);
mDatabase = FirebaseDatabase.getInstance().getReference();
mRecycler = (RecyclerView)rootView.findViewById(R.id.freeboard_messages_list);
mRecycler.setHasFixedSize(true);
return rootView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState)
{
super.onActivityCreated(savedInstanceState);
mManager = new LinearLayoutManager(getActivity());
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
mRecycler.setLayoutManager(mManager);
Query postsQuery = getQuery(mDatabase);
mAdapter = new FirebaseRecyclerAdapter<FreeboardPost, FreeboardPostViewHolder>(FreeboardPost.class, R.layout.freeboard_item_post, FreeboardPostViewHolder.class, postsQuery)
{
@Override
protected void populateViewHolder(final FreeboardPostViewHolder viewHolder, final FreeboardPost model, final int position)
{
final DatabaseReference postRef = getRef(position);
final String postKey = postRef.getKey();
mPostReference = FirebaseDatabase.getInstance().getReference().child("FreeboardPost").child(postKey);
viewHolder.itemView.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
Intent intent = new Intent(getActivity(), FreeBoardPostDetailActivity.class);
intent.putExtra(FreeBoardPostDetailActivity.EXTRA_POST_KEY, postKey);
startActivity(intent);
}
});
if(model.stars.containsKey(getUid()))
{
viewHolder.freeboardstarView.setImageResource(R.drawable.ic_toggle_star_24);
}
else
{
viewHolder.freeboardstarView.setImageResource(R.drawable.ic_toggle_star_outline_24);
}
viewHolder.bindToPost(model, new View.OnClickListener()
{
@Override
public void onClick(View starView)
{
DatabaseReference globalPostRef = mDatabase.child("FreeboardPost").child(postRef.getKey());
DatabaseReference userPostRef = mDatabase.child("FreeboardUserPost").child(model.uid).child(postRef.getKey());
onStarClicked(globalPostRef);
onStarClicked(userPostRef);
}
});
}
};
mRecycler.setAdapter(mAdapter);
}
private void onStarClicked(DatabaseReference postRef)
{
postRef.runTransaction(new Transaction.Handler()
{
@Override
public Transaction.Result doTransaction(MutableData mutableData)
{
FreeboardPost p = mutableData.getValue(FreeboardPost.class);
if(p == null)
{
return Transaction.success(mutableData);
}
if(p.stars.containsKey(getUid()))
{
p.starCount = p.starCount - 1;
p.stars.remove(getUid());
}
else
{
p.starCount = p.starCount + 1;
p.stars.put(getUid(), true);
}
mutableData.setValue(p);
return Transaction.success(mutableData);
}
@Override
public void onComplete(DatabaseError databaseError, boolean b, DataSnapshot dataSnapshot)
{
}
});
}
public String getUid()
{
return FirebaseAuth.getInstance().getCurrentUser().getUid();
}
public abstract Query getQuery(DatabaseReference databaseReference);
}
这是freeboard_include_post_author.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:gravity="center_vertical"
android:orientation="horizontal">
<de.hdodenhof.circleimageview.CircleImageView
android:id="@+id/freeboard_post_author_photo"
android:layout_width="40dp"
android:layout_height="40dp"
app:civ_border_width="2dp"
app:civ_border_color="#FF000000">
</de.hdodenhof.circleimageview.CircleImageView>
<TextView
android:id="@+id/freeboard_post_author"
style="@style/Base.TextAppearance.AppCompat.Small"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:gravity="center_vertical"
tools:text="someauthor@email.com" />
</LinearLayout>
这是freeboard_item_post.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="1dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp">
<ImageView
android:id="@+id/freeboard_post_image"
android:layout_width="90dp"
android:layout_height="90dp"
android:layout_marginRight="10dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:scaleType="centerCrop"
android:src="@drawable/profile"/>
<RelativeLayout
android:id="@+id/freeboard_text_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_toRightOf="@id/freeboard_post_image">
<LinearLayout
android:id="@+id/freeboard_star_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/freeboard_post_author_layout"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/freeboard_post_author_layout"
android:gravity="center_vertical"
android:orientation="horizontal">
<ImageView
android:id="@+id/freeboard_star"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginRight="5dp"
android:background="?attr/selectableItemBackground"
android:src="@drawable/ic_toggle_star_outline_24" />
<TextView
android:id="@+id/freeboard_post_num_stars"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
tools:text="7" />
</LinearLayout>
<include
android:id="@+id/freeboard_post_text"
layout="@layout/freeboard_include_post_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_marginLeft="5dp"
android:layout_marginTop="10dp" />
<include
android:id="@+id/freeboard_post_author_layout"
android:layout_below="@+id/freeboard_post_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
layout="@layout/freeboard_include_post_author"
android:layout_marginTop="10dp"
android:layout_alignParentLeft="true" />
</RelativeLayout>
</RelativeLayout>
</android.support.v7.widget.CardView>
非常感谢您阅读我的长码。我很难用星形按钮显示用户的图像。当我点击星标时，firebase立即从同一个孩子中删除“图像”值。
这是在我点击星标之前
这是在我点击星形按钮之后。
我100％确定没有删除子项或值的代码..但为什么它会从子项中删除我的图像地址..？我很好奇。谢谢！
1 个答案:
答案 0 :(得分：0)
您没有发布在数据库中创建FreeboardPost实例的代码。我猜你正在使用toMap()，因为它将图片网址存储在名为image的字段中，该字段显示在您发布的数据库示例中。
在您的交易中，您使用Firebase来序列化/反序列化FreeboardPost。它希望在名为imageUrl的字段中找到图像URL，因为这是您班级中的公共字段名称。当您发布的节点被读取时，没有名为imageUrl的字段，因此创建的FreeboardPost实例对该字段值为null。编写实例时，没有为imageUrl写入值，因为它为空，并且image的先前数据库值丢失，因为FreeboardPost没有具有该名称的字段。
如果要使用Firebase功能序列化/反序列化FreeboardPost，则应将它们用于所有数据库读取和写入。使用带有映射的updateMap()或setValue()来编写实例，然后使用POJO类来读取命名不匹配的风险。
相关问题
最新问题
- 我写了这段代码，但我无法理解我的错误
- 我无法从一个代码实例的列表中删除 None 值，但我可以在另一个实例中。为什么它适用于一个细分市场而不适用于另一个细分市场？
- 是否有可能使 loadstring 不可能等于打印？卢阿
- java中的random.expovariate()
- Appscript 通过会议在 Google 日历中发送电子邮件和创建活动
- 为什么我的 Onclick 箭头功能在 React 中不起作用？
- 在此代码中是否有使用“this”的替代方法？
- 在 SQL Server 和 PostgreSQL 上查询，我如何从第一个表获得第二个表的可视化
- 每千个数字得到
- 更新了城市边界 KML 文件的来源？