firebase-在 Firabase DB Java 中检查子项的值
发布时间:2022-08-07 11:54:56 209
相关标签: # 移动端
我正在尝试从我的数据库中选择数据,并且我想检查特定子节点的值是 1 还是 0。如果它有一个 1 那么我不想显示来自该特定用户的信息。如果它为零,那么我想显示来自该特定用户的信息。
我是在我正在研究的方法之上的一种方法中做到的(我遵循了这个答案How to get child of child value from firebase in android?),我让它工作没问题。但是我不能对我的其他方法做同样的事情,我现在整天都在尝试。
截至目前,我得到的唯一结果是列表根本没有出现。有人可以帮帮我吗 ?
有效的方法:
private void getPosts() {
followingList = new ArrayList<>();
DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Video_Posts");
FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
myPosts.clear();
//followingList.clear();
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
Post post = snapshot.getValue(Post.class);
if (followingList.isEmpty()) {
if (!post.getPublisher().equals(firebaseUser.getUid())) {
DatabaseReference zonesRef = FirebaseDatabase.getInstance().getReference("Users");
DatabaseReference zone1Ref = zonesRef.child(post.getPublisher());
DatabaseReference zone1NameRef = zone1Ref.child("acc_closed");
zone1NameRef.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
//Log.i(TAG, dataSnapshot.getValue(String.class));
if (dataSnapshot.getValue(String.class).equals("1")) {
//Toast.makeText(getContext(), "Account closed", Toast.LENGTH_SHORT).show();
} else if (dataSnapshot.getValue(String.class).equals("0")) {
//Toast.makeText(getContext(), "Not closed.", Toast.LENGTH_SHORT).show();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
Query query = rootRef
.child("Follow")
.child(firebaseUser.getUid())
.child("following")
.child(post.getPublisher());
ValueEventListener valueEventListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
//Do something
Toast.makeText(getContext(), "Following.", Toast.LENGTH_SHORT).show();
} else {
//Do something else
myPosts.add(post);
Collections.shuffle(myPosts);
//Toast.makeText(getContext(), "Something.", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
};
query.addListenerForSingleValueEvent(valueEventListener);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
//Log.w(TAG, "onCancelled", databaseError.toException());
}
});
} else if (myPosts == null) {
Toast.makeText(getContext(), "Nothing.", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(getContext(), "List is not empty.", Toast.LENGTH_SHORT).show();
for (String id : followingList) {
assert post != null;
if (!post.getPublisher().equals(id)) {
myPosts.add(post);
Toast.makeText(getContext(), "Something.", Toast.LENGTH_SHORT).show();
} else if (myPosts == null) {
Toast.makeText(getContext(), "Nothing.", Toast.LENGTH_SHORT).show();
}
}
}
}
adapterExplorer.notifyDataSetChanged();
progressBar.setVisibility(View.GONE);
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});
}
不起作用的方法:
private void searchUsers(String s) {
Query query = FirebaseDatabase.getInstance().getReference("Users");
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (search_bar.getText().toString().equals("")) {
recyclerView.setVisibility(View.INVISIBLE);
}
mUsers.clear();
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
User user = snapshot.getValue(User.class);
DatabaseReference zonesRef = FirebaseDatabase.getInstance().getReference("Users");
DatabaseReference zone1Ref = zonesRef.child(user.getId());
DatabaseReference zone1NameRef = zone1Ref.child(user.getAcc_closed());
//mUsers.add(user);
zone1NameRef.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapS) {
if (snapS.getKey().equals("1")) {
} else if (snapS.getKey().equals("0")){
//if (!snapS.exists()) {
Log.d("TAG", snapS.toString());
mUsers.add(user);
//}
}
//}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
Log.d("Error name", error.getMessage());
}
});
}
userAdapter.notifyDataSetChanged();
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
Log.d("Error name", error.getMessage());
}
});
}
数据库:
"Users": {
"4mFQt8Lf3CTNrQF74sy8wwyFoLh1": {
"acc_closed": "0",
"bio": "",
"dateAdded": "19-06-2022 17:28:56",
"date_time": 1655674136805,
"device_token": "feGjHNzaR7S8yaV2HKg0rt:APA91bEXAiYwT52niHVxR2ENrcaKXSNs11Z5ss-g2gsDwTs4wbjqjcrN4ZUmemqiMzp6SZM6UXD5TFrc1JND_DoEgd-Ni9wMeCa73EzvKBAaj5aXJf1GjgjSsTVwBg1A6VvhvVwF1VSX",
"fullname": "Brandon",
"id": "4mFQt8Lf3CTNrQF74sy8wwyFoLh1",
"imageurl": "https://img.hake.cc/other_net_images/other_images_skf/default.jpg?alt=media&token=befece91-9248-45ee-ab6f-b1b3d217c6b4",
"username": "bran1",
"verified": "false"
},
编辑:
上面的代码(searchUsers
)一种工作。当我把文字放进搜索栏时,什么也没有显示。但当我点击后退按钮并移除键盘时,数据显示出来。这就像我在等待数据的变化。
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