Android facebook login integration

Question

i am trying to implement facebook login to my app , the graph response is null and i can't get any user information , here is my code

public class LoginActivity extends AppCompatActivity {

CallbackManager callbackManager;
LoginButton login;
private String text;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_login_page);
   FacebookSdk.sdkInitialize(getApplicationContext());
    callbackManager = CallbackManager.Factory.create();
    login = (LoginButton)findViewById(R.id.login_button);
    login.setReadPermissions("public_profile email");
    login.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            if(AccessToken.getCurrentAccessToken() != null){
                RequestData();
            }
        }

        @Override
        public void onCancel() {

        }

        @Override
        public void onError(FacebookException exception) {
        }
    });


        @Override
        public void onCancel() {

        }

        @Override
        public void onError(FacebookException exception) {
        }
    });


}


public void RequestData(){

    GraphRequest request = GraphRequest.newMeRequest(AccessToken.getCurrentAccessToken()
            , new GraphRequest.GraphJSONObjectCallback() {
        @Override
        public void onCompleted(JSONObject object,GraphResponse response) {

            JSONObject json = response.getJSONObject();
            try {
                if(json != null){
                    text = json.getString("id");
  Context context=getApplicationContext();
    Toast.makeText(context,text,Toast.LENGTH_LONG).show();
                }
  else{
     Toast.makeText(context,"empty",Toast.LENGTH_LONG).show();
     }

            } catch (JSONException e) {
                e.printStackTrace();

            }
        }
    });
    Bundle parameters = new Bundle();
    parameters.putString("fields", "id,name,link,email,picture");
    request.setParameters(parameters);
    request.executeAsync();
    Context context=getApplicationContext();
    Toast.makeText(context,text,Toast.LENGTH_LONG).show();
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    callbackManager.onActivityResult(requestCode, resultCode, data);
}

}

the toast message is always empty and no info returning , i am stuck in this

Answer 1

我将注册呼叫从按钮更改为登录管理器，并且成功了