boolean java.lang.String.equals(java.lang.Object)' on a null object reference error in ParseFacebookUtils.logInWithReadPermissionsBackground

Question

I am trying to login into facebook using parse. Below is my code.

Button fbLoginButton = (Button)findViewById(R.id.login_facebook);
final List<String> permission = Arrays.asList("public_profile", "User_friends");
        fbLoginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ParseFacebookUtils.logInWithReadPermissionsInBackground(MainActivity.this, permission, new LogInCallback() {
                    @Override
                    public void done(ParseUser parseUser, ParseException e) {
                        if(parseUser == null) {
                            Log.d("ParseUser" , "User cancelled login");
                        } else if(parseUser.isNew()) {
                            Log.d("New User", "User signed up and logged in using facebook");
                        } else {
                            Log.d("ParseUser", "user logged in using facebook");
                        }
                    }
                } );
            }
        });

I am getting java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference while running the app. In the log its also showing that the error is at line 146. at com.example.gopi.layouts_test.MainActivity$2.onClick(MainActivity.java:146)

Line number 146 in my code is ParseFacebookUtils.logInWithReadPermissionsInBackground(MainActivity.this, permission, new LogInCallback() {

I tried hashing out the first if condition like below.

/*if(parseUser == null) {
                            Log.d("ParseUser" , "User cancelled login");
                        } else */

Still I am getting the same error at same line number.

Full Stack trace:

04-30 05:38:25.763    1233-1233/com.example.gopi.layouts_test E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.gopi.layouts_test, PID: 1233
    java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equals(java.lang.Object)' on a null object reference
            at com.facebook.login.LoginManager.getLogger(LoginManager.java:391)
            at com.facebook.login.LoginManager.logCompleteLogin(LoginManager.java:414)
            at com.facebook.login.LoginManager.startLogin(LoginManager.java:384)
            at com.facebook.login.LoginManager.logInWithReadPermissions(LoginManager.java:262)
            at com.parse.FacebookAuthenticationProvider.authenticateAsync(FacebookAuthenticationProvider.java:155)
            at com.parse.ParseAuthenticationProvider.logInAsync(ParseAuthenticationProvider.java:50)
            at com.parse.ParseFacebookUtils.logInAsync(ParseFacebookUtils.java:265)
            at com.parse.ParseFacebookUtils.logInWithReadPermissionsInBackground(ParseFacebookUtils.java:161)
            at com.parse.ParseFacebookUtils.logInWithReadPermissionsInBackground(ParseFacebookUtils.java:173)
            at com.example.gopi.layouts_test.MainActivity$2.onClick(MainActivity.java:146)
            at android.view.View.performClick(View.java:4780)
            at android.view.View$PerformClick.run(View.java:19866)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5254)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

Please help me.

Answer 1

I have include the meta-data tag inside the application tag in manifest, which resolved the issue.

Include the following inside application tag.

<meta-data
        android:name="com.facebook.sdk.ApplicationId"
        android:value="@string/facebook_app_id"/>

Thanks