Facebook Login SDK exception android?

Question

I am implementing the FB SDK in my project Android Studio.

This is my code

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    FacebookSdk.sdkInitialize(getApplicationContext());
    callbackManager = CallbackManager.Factory.create();
    setContentView(R.layout.activity_login);
    loginButton = (LoginButton) findViewById(R.id.login_button);
    loginButton.setReadPermissions("user_friends");
   }

I am getting the below exception

java.lang.RuntimeException: An error occured while executing doInBackground()
        at android.os.AsyncTask$3.done(AsyncTask.java:300)
        at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
        at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
        at java.util.concurrent.FutureTask.run(FutureTask.java:242)
        at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
        at java.lang.Thread.run(Thread.java:841)
 Caused by: java.lang.NullPointerException
        at java.util.concurrent.ConcurrentHashMap.containsKey(ConcurrentHashMap.java:911)
        at com.facebook.internal.Utility.queryAppSettings(Utility.java:802)
        at com.facebook.login.widget.LoginButton$1.doInBackground(LoginButton.java:502)
        at com.facebook.login.widget.LoginButton$1.doInBackground(LoginButton.java:499)
            at android.os.AsyncTask$2.call(AsyncTask.java:288)
        at java.util.concurrent.FutureTask.run(FutureTask.java:237)

Answer 1

在Strings.xml中添加app_id ..它应类似于<string name="app_id">1234569xxxxxxxx</string> :)