在实时数据库“ firebase”中处理错误情况的方法

Question

Im trying to write on firebase realtime database via my android app using setValue() it works very well.. but i don't know how i can handle the error if something goes wrong

i tried try/catch and turning off the WIFI so the setValue function won't work but it didn't seem to catch any exception

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("message");
try{
    myRef.setValue("Hello, World!"); 
}catch(Exception e){
    e.printStackTrace();
}

Answer 1

There are many methods you can use to handle this. You can set any of several listeners to monitor the result state of a setValue() call:

• onCompleteListener()
• onFailureListener()
• onSuccessListener()

My personal preference is the onCompleteListener() because it allows me to simultaneously check for success and failure with minimal lines of code. Here's an implementation:

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("message");

myRef.setValue("Hello, World!").addOnCompleteListener(new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {
            if(task.isSuccessful()) {
                // handle success event
            }
            else {
                // handle failure event
                // You can get the exact exception using task.getException()
            }
        }
    });

I hope this helps. Merry coding!

Answer 2

You can use Completion Callback .

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("message");
myRef.setValue("Hello, World!")
       .addOnSuccessListener(new OnSuccessListener<Void>() {
        @Override
        public void onSuccess(Void aVoid) {
            // Write was successful!
            // ...
        }
    })
    .addOnFailureListener(new OnFailureListener() {
        @Override
        public void onFailure(@NonNull Exception e) {
            // Write failed
            // ...
        }
    });