从Firebase数据库中移除特定值 [英] Remove Specific value From Firebase Database
本文介绍了从Firebase数据库中移除特定值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想从Firebase数据库中删除特定值,以下是我存储的数据库:
我尝试从Firebase中删除特定值。
DatabaseReference demo = mReference.child(演示 )orderByValue()equalTo( 约翰)getRef()。
demo.addListenerForSingleValueEvent(new ValueEventListener(){
@Override
public void onDataChange(DataSnapshot dataSnapshot){
dataSnapshot.getRef()。removeValue();
}
@Override
public void onCancelled(DatabaseError databaseError){
});
但是这会删除数据库中的所有值...
问题
:如何删除特定的值?我必须做的是
任何帮助将不胜感激。
解决方案使用
addListenerForSingleValueEvent
尝试使用下面的 addChildEventListener
, 查询queryRef = mReference.child(demo)。orderByChild(fname)。equalTo(John);
queryRef.addChildEventListener(new ChildEventListener(){
@Override $ b $ public void onChildAdded(DataSnapshot snapshot,String previousChild){
snapshot.getRef()。setValue null);
}
});
I want to Delete Specific value from Firebase Database following is Database which i have stored
Now, I want to Delete Following Values
fname: "John"
lname: "wick"
Here, What i have try to delete specific value from Firebase..
DatabaseReference demo = mReference.child("demo").orderByValue().equalTo("John").getRef();
demo.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
dataSnapshot.getRef().removeValue();
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
But this will delete all values from database...
Question
: How to delete that specific value??? what i have to do for that
Any help will be appreciated.
解决方案
Instead of using addListenerForSingleValueEvent
try using addChildEventListener
as below,
Query queryRef = mReference.child("demo").orderByChild("fname").equalTo("John");
queryRef.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot snapshot, String previousChild) {
snapshot.getRef().setValue(null);
}
});
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