访问子节点时出现问题.(增量报告)

Question

这是我的数据结构。

"Posts" : {
"-MpVVpVIqmn0Iu78hDRp" : {
"description" : "",
"picture" : "",
"postKey" : "",
"reports" : 0,
"timeStamp" : 1638001760487,
"title" : "",
"userId" : "",
"userPhoto" : ""
},
"-MpVcioadtvRBRaa0n96" : {
"description" : "",
"picture" : "",
"postKey" : "",
"reports" : 0,
"timeStamp" : 1638003830234,
"title" : "",
"userId" : "",
"userPhoto" : ""
},

我想访问"；报告"；部分所以我用

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
rootRef.child("Posts").child("reports").setValue(1);

但它创建的报告值1正好在Posts not below"-MpVVpVIqmn0Iu78hDRp"；这我想增加这份报告。但我不知道如何接近报表节点。

这是我的完整代码

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_post_detail);
imm = (InputMethodManager)getSystemService(INPUT_METHOD_SERVICE);
et = (EditText)findViewById(R.id.post_detail_comment);

// let's set the statue bar to transparent

// ini Views
RvComment = findViewById(R.id.rv_comment);
imgPost =findViewById(R.id.post_detail_img);
imgUserPost = findViewById(R.id.post_detail_user_img);
imgCurrentUser = findViewById(R.id.post_detail_currentuser_img);
txtPostTitle = findViewById(R.id.post_detail_title);
txtPostDesc = findViewById(R.id.post_detail_desc);
txtPostDateName = findViewById(R.id.post_detail_date_name);
editTextComment = findViewById(R.id.post_detail_comment);
btnAddComment = findViewById(R.id.post_detail_add_comment_btn);
btnDeletePost = findViewById(R.id.button_delete);
btnnoti = findViewById(R.id.button_noti);
btncommentnoti = findViewById(R.id.comment_noti);

firebaseAuth = FirebaseAuth.getInstance();
firebaseUser = firebaseAuth.getCurrentUser();
firebaseDatabase = FirebaseDatabase.getInstance();
// add post delete button
mDatabase= FirebaseDatabase.getInstance().getReference();
myUid = FirebaseAuth.getInstance().getCurrentUser().getUid();
//게시글 신고기능
btnnoti.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
rootRef.child("Posts").child("reports").setValue(1);
}
});
btnDeletePost.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//여기 수정 주의 UId.equals(myUid)
if (true){
Toast.makeText(PostDetailActivity.this,"삭제중...",Toast.LENGTH_SHORT).show();
beginDelete();
onBackPressed();
}
}
});
// add Comment button click listener
btnAddComment.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
btnAddComment.setVisibility(View.INVISIBLE);
DatabaseReference commentReference = firebaseDatabase.getReference(COMMENT_KEY).child(PostKey).push();
String comment_content = editTextComment.getText().toString();
String uid = firebaseUser.getUid();
String uname = firebaseUser.getDisplayName();
if (firebaseUser.getPhotoUrl()!=null){
String uimg = firebaseUser.getPhotoUrl().toString();
Comment comment = new Comment(comment_content,uid,uimg,uname);
commentReference.setValue(comment).addOnSuccessListener(new OnSuccessListener<Void>() {
@Override
public void onSuccess(Void aVoid) {
showMessage("댓글이 등록되었습니다.");
editTextComment.setText("");
btnAddComment.setVisibility(View.VISIBLE);
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
showMessage("fail to add comment : "+e.getMessage());
}
});
}
else{
String usphoto =Integer.toString(R.drawable.userphoto);
Comment comment = new Comment(comment_content,uid,usphoto,uname);
commentReference.setValue(comment).addOnSuccessListener(new OnSuccessListener<Void>() {
@Override
public void onSuccess(Void aVoid) {
showMessage("comment added");
editTextComment.setText("");
btnAddComment.setVisibility(View.VISIBLE);
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
showMessage("fail to add comment : "+e.getMessage());
}
});
}


}
});

// now we need to bind all data into those views
// first we need to get post data
// we need to send post detail data to this activity first ...
// now we can get post data

// 게시글 사진 백지 케이스
postImage = getIntent().getExtras().getString("postImage") ;
if(postImage!=null){
Glide.with(this).load(postImage).into(imgPost);
}
else{
Glide.with(this).load(R.drawable.whitepaper).into(imgPost);
}

String postTitle = getIntent().getExtras().getString("title");
txtPostTitle.setText(postTitle);
String userpostImage = getIntent().getExtras().getString("userPhoto");
if (userpostImage!=null){
Glide.with(this).load(userpostImage).into(imgUserPost);
}
else {
Glide.with(this).load(R.drawable.userphoto).into(imgUserPost);
}
String postDescription = getIntent().getExtras().getString("description");
txtPostDesc.setText(postDescription);
// set comment user image
if (firebaseUser.getPhotoUrl()!=null){
Glide.with(this).load(firebaseUser.getPhotoUrl()).into(imgCurrentUser);
}
else{
Glide.with(this).load(R.drawable.userphoto).into(imgCurrentUser);
}
// get post key
PostKey = getIntent().getExtras().getString("postKey");
String date = timestampToString(getIntent().getExtras().getLong("postDate"));
txtPostDateName.setText(date);
// get post uid
UId = getIntent().getExtras().getString("userId");

// ini Recyclerview Comment
iniRvComment();

}
private void beginDelete() {

//서버 관리용 개발자 옵션
if (myUid.equals("k1kn0JF5idhrMzuw46GarEIBgPw2")) {
long tlong = System.currentTimeMillis(); long ttime;
ttime = tlong - 3*24*60*60*1000;
DatabaseReference db = FirebaseDatabase.getInstance().getReference();
Query queryByTimestamp = db.child("Posts").orderByChild("timeStamp").endAt(ttime);
queryByTimestamp.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
@Override
public void onComplete(@NonNull Task<DataSnapshot> task) {
if (task.isSuccessful()) {
for (DataSnapshot ds : task.getResult().getChildren()) {
ds.getRef().removeValue();
Toast.makeText(PostDetailActivity.this,"게시글이 삭제되었습니다.",Toast.LENGTH_SHORT).show();
}
} else {
Log.d("TAG", task.getException().getMessage());
Toast.makeText(PostDetailActivity.this,"게시글이 삭제되지않았습니다.",Toast.LENGTH_SHORT).show();
}
}
});
}
else if (UId.equals(myUid)) {
DatabaseReference db = FirebaseDatabase.getInstance().getReference();
Query queryByTimestamp = db.child("Posts").orderByChild("postKey").equalTo(PostKey);
queryByTimestamp.get().addOnCompleteListener(new OnCompleteListener<DataSnapshot>() {
@Override
public void onComplete(@NonNull Task<DataSnapshot> task) {
if (task.isSuccessful()) {
for (DataSnapshot ds : task.getResult().getChildren()) {
ds.getRef().removeValue();
Toast.makeText(PostDetailActivity.this, "게시글이 삭제되었습니다.", Toast.LENGTH_SHORT).show();
}
} else {
Log.d("TAG", task.getException().getMessage());
Toast.makeText(PostDetailActivity.this, "게시글이 삭제되지않았습니다.", Toast.LENGTH_SHORT).show();
}
}
});
}
else{
Toast.makeText(PostDetailActivity.this,"다른 사용자의 게시글입니다.",Toast.LENGTH_SHORT).show();
}
}
public void linearOnClick(View v) {
imm.hideSoftInputFromWindow(et.getWindowToken(), 0);
}

private void iniRvComment() {
RvComment.setLayoutManager(new LinearLayoutManager(this));
DatabaseReference commentRef = firebaseDatabase.getReference(COMMENT_KEY).child(PostKey);
commentRef.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
listComment = new ArrayList<>();
for (DataSnapshot snap:dataSnapshot.getChildren()) {
Comment comment = snap.getValue(Comment.class);
listComment.add(comment) ;
}
commentAdapter = new CommentAdapter(getApplicationContext(),listComment);
RvComment.setAdapter(commentAdapter);

}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});


}
private void showMessage(String message) {
Toast.makeText(this,message,Toast.LENGTH_LONG).show();
}

private String timestampToString(long time) {
Calendar calendar = Calendar.getInstance(Locale.ENGLISH);
calendar.setTimeInMillis(time);
String date = DateFormat.format("yyyy-MM-dd",calendar).toString();
return date;

}

}

这是我问题的一部分

btnnoti.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
rootRef.child("Posts").child("reports").setValue(1);
}
});

我也尝试过orderbychild，但我认为这不是正确的代码。

Answer 1

此代码：

rootRef.child("Posts").child("reports").setValue(1);

您正在告诉数据库将/Posts/reports的值设置为1，这正是它所要做的。

---

如果要增加节点的当前值，可以使用原子增量操作：

rootRef.child("Posts").child("reports").setValue(ServerValue.increment(1));

---

如果要在Posts下增加特定节点的reports属性，则需要知道该节点的密钥。例如：

rootRef.child("Posts/-MpVVpVIqmn0Iu78hDRp/reports").setValue(ServerValue.increment(1));

---

如果您不知道要递增的节点的键，但确实知道其他一些唯一(足够(标识要更新的节点的值，则可以使用查询来查找键。

例如，要使用特定的postKey:更新所有节点

Query query = rootRef.child("Posts").orderByChild("postKey").equalTo("thePostKeyValue");
query.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
postSnapshot.getReference().child("reports").setValue(ServerValue.increment(1));
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException();
}
}