Android - Firebase searching with filtering

问题

I'm developing an app that will help the user to search the books and download them which have been uploaded by other users as a form of the post.

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In order to download the books first, the user should search them owing to attribute such as Title.

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The posts which meet the requirement of the user should be displayed in the firebase-UI recyclerview.

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This is my Firebase data structure:

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I want the sample code that will create a Query which returns Id of convenient Posts such as ImgBRr2YFYfAu1WwENS1Ucj6jz13_1514813350760.

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Please help me to solve the problem, any suggestions and ideas will be welcomed

回答1:

Here is what you can do,

For search by language and then filter by title & author

public void search(String languangeSearchString, String title, String author){  
        FirebaseDatabase.getInstance().getReference().child("Posts").equalTo("language").startAt(languangeSearchString).addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
                 String id = dataSnapshot.getKey();
                if(dataSnapshot.child("title").exists() && dataSnapshot.child("author").exists()){
                    if(dataSnapshot.child("title").getValue(String.class).equals(title) && dataSnapshot.child("author").getValue(String.class).equals(author)){
                        //Here are the results
                    }
                }           
            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

}

回答2:

To perform searching on firebase-database, we commonly use orderBy(). Like

firebaseDatabase.getReference("Posts").child("postId")
                        .orderBy("authorId")

But it can't possible to use multiple orderBy() like,

firebaseDatabase.getReference("Posts").child("postId")
                     .orderBy("authorId")
                     .orderBy("title")     // this will throw an error
                     .orderBy("language") 

So you have to perform searching only on one child-node. For more info check this Query based on multiple where clauses in Firebase

来源：https://stackoverflow.com/questions/48061546/android-firebase-searching-with-filtering