android - GraphRequest 在尝试获取用户 onCompleted 的 ID 时抛出 NullPointerException？

Question

我几乎 95% 的用户都顺利通过了登录过程，但有时我在尝试时遇到此异常:editor.putString("fbId", id)。为什么？如果 onSuccess 被调用，我假设该对象已经被填充，那么为什么会出现错误或可能的空响应？

请帮帮我，我快疯了!

谢谢!

异常(exception):

Android Version: android version: 4.3

java.lang.NullPointerException at com.cerculdivelor.SplashActivity$2$1.onCompleted(SplashActivity.java:90) at com.facebook.GraphRequest$1.onCompleted(GraphRequest.java:304) at com.facebook.GraphRequest$5.run(GraphRequest.java:1379) at android.os.Handler.handleCallback(Handler.java:730) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:176) at android.app.ActivityThread.main(ActivityThread.java:5419) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:525) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862) at dalvik.system.NativeStart.main(Native Method)

方法:

private void onFblogin() {
        LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList(
                "public_profile", "email"));

        LoginManager.getInstance().registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
            @Override
            public void onSuccess(LoginResult loginResult) {
                // App code
                GraphRequest request = GraphRequest.newMeRequest(
                        loginResult.getAccessToken(),
                        new GraphRequest.GraphJSONObjectCallback() {
                            @Override
                            public void onCompleted(JSONObject object, GraphResponse response) {
                                Log.v("LoginActivity", response.toString());

                                // Application code
                                try {

               /*** line 90 -->***/ String id = object.getString("id");
                                    String name = object.getString("name");
                                    String email = object.getString("email");
                                    //String birthday = object.getString("birthday"); <-- error if people don't have this completed

                                    Log.i("TAG", email + " " + id + " " + " " + name);

                                    SharedPreferences.Editor editor = getSharedPreferences("user", MODE_PRIVATE).edit();
                                    editor.putString("fbId", id);
                                    editor.putString("name", name);
                                    editor.putString("email", email);
                                    editor.commit();

                                    HttpConActivity http = new HttpConActivity(getApplication());
                                    http.saveToServer(id, name, email);

                                    finish();

                                } catch (JSONException e) {
                                    e.printStackTrace();
                                }
                            }
                        });
                Bundle parameters = new Bundle();
                parameters.putString("fields", "id,name,email,gender");
                request.setParameters(parameters);
                request.executeAsync();


            }

            @Override
            public void onCancel() {
                Log.i("TAG", "Canceled!");
            }

            @Override
            public void onError(FacebookException e) {
                Log.i("TAG", "Error!");
            }
        });

Answer 1

只需检查 GraphJSONObjectCallback - GraphResponse 中的错误。文档说，JSONObject 对象 可以为空，因此您不应假设它不为空。

请记住，您是在与服务器通信。您应该始终预料到错误并加以处理。

所以像这样:

@Override
public void onCompleted(JSONObject object, GraphResponse response) {

    FacebookRequestError error = response.getError();
    if (error != null) {
        // handle your error
        return;
    }

    try {
        String id = object.getString("id");
        ...