RequestVerifyCode.java

Task<VerifyCodeResult> task = EmailAuthProvider.requestVerifyCode(emailEditText.getText().toString(), verifyCodeSettings);
        task.addOnSuccessListener(TaskExecutors.uiThread(), new OnSuccessListener<VerifyCodeResult>() {
            @Override
            public void onSuccess(VerifyCodeResult verifyCodeResult) {
                Toast.makeText(getApplicationContext(), "Please check your e-mail", Toast.LENGTH_SHORT).show();
            }
        }).addOnFailureListener(TaskExecutors.uiThread(), new OnFailureListener() {
            @Override
            public void onFailure(Exception e) {
                Toast.makeText(getApplicationContext(), e.getLocalizedMessage(), Toast.LENGTH_SHORT).show();
            }
        });