我目前正在开发一个Android应用程序,该应用程序将Firebase(实时功能)用作后端服务.另外,我已经开发了此功能,如下所示.

private void checkUserExisting (){

Dataa = mRef.getReference().child("Users");

Dataa.addListenerForSingleValueEvent(new ValueEventListener() {

@Override

public void onDataChange(DataSnapshot dataSnapshot) {

if (!dataSnapshot.exists()){

CreateUserProfile();

}else {

final String Uname = name.getText().toString().trim();

final String Email = emailAddress.getText().toString().trim();

Iterator dataSnapshots = dataSnapshot.getChildren().iterator();

while (dataSnapshots.hasNext())

{

DataSnapshot dataSnapshotChild = dataSnapshots.next();

String EmailAddress = dataSnapshotChild.child("Email").toString();

String UserName = dataSnapshotChild.child("UserName").toString();

if (Uname.equals(UserName) || Email.equals(EmailAddress)){

Toast.makeText(Sgin_Up.this,"This user already exists",Toast.LENGTH_LONG).show();

break;

}else {

CreateUserProfile();

}

}

}

}

@Override

public void onCancelled(DatabaseError databaseError) {

}

});

扩展

该代码工作得很好,并且它检查现有数据并显示Toast消息,但是在数据仍然进入数据库后,我想使重复数据无效.