Android-保存对象时Parse.com NullPointerException

Question

In my app I am using Parse.com and Facebook login, and the Facebook login is working and I am now trying to save the email of the user who signed. I am doing this like this:

Request.newMeRequest(ParseFacebookUtils.getSession(), new Request.GraphUserCallback() {

        // callback after Graph API response with user object
        @Override
        public void onCompleted(GraphUser user, Response response) {
            if (user != null) {
                String email = user.getProperty("email").toString();
                Log.i(TAG, email);
                ParseUser currentUser = ParseUser.getCurrentUser();
                currentUser.put("email", email);
                currentUser.saveInBackground();

            }
        }
    }).executeAsync()

But then when I run I get java.lang.NullPointerException at this line currentUser.put("email", email); But I log email before this and it is not null and I have a email attribute in my User class on parse, so Im not sure why this?

Here the code that comes before to set up the FB Login you should need it and it is working but just in case.

public void onLoginClick(View v) {
    progressDialog = ProgressDialog.show(LoginActivity.this, "", "Logging in...", true);

    final List<String> permissions = Arrays.asList("public_profile", "email");
    // NOTE: for extended permissions, like "user_about_me", your app must be reviewed by the Facebook team
    // (https://developers.facebook.com/docs/facebook-login/permissions/)

    ParseFacebookUtils.logIn(permissions, this, new LogInCallback() {
        @Override
        public void done(ParseUser user, ParseException err) {
            progressDialog.dismiss();
            if (user == null) {
                Log.d(TAG, "Uh oh. The user cancelled the Facebook login.");
            } else if (user.isNew()) {
                Log.d(TAG, "User signed up and logged in through Facebook!");
                showSelectSchoolActivity();
            } else {
                Log.d(TAG, "User logged in through Facebook!");
                showMainActivity();
            }
        }
    });

Thanks for the help :)

Answer 1

for checking the response you should always use (err==null) as the condition for success. Only after you have recieved the response from the server and err==null then you can check for current user. You should also have a check for when err!=null. Then get the error message from the err.getCode() and check what the error code is.