app forcecloses on starting facebook activity

Question

I have integrated facebook sdk in my android studio project but app force closes as soon as i run the app. There is jsonexception error in designer where i have used com.facebook.login.widget.LoginButton, but it is only a designer error.

error log:

> 04-17 19:29:35.996  24734-24734/com.example.bandhan.myapplication1
> E/AndroidRuntime﹕ FATAL EXCEPTION: main
>     Process: com.example.bandhan.myapplication1, PID: 24734
>     java.lang.ExceptionInInitializerError
>             at java.lang.reflect.Constructor.newInstance(Native Method)
>             at java.lang.reflect.Constructor.newInstance(Constructor.java:288)
>             at android.view.LayoutInflater.createView(LayoutInflater.java:614)
>             at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:750)
>             at android.view.LayoutInflater.rInflate(LayoutInflater.java:813)
>             at android.view.LayoutInflater.inflate(LayoutInflater.java:511)
>             at android.view.LayoutInflater.inflate(LayoutInflater.java:415)
>             at android.view.LayoutInflater.inflate(LayoutInflater.java:366)
>             at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:435)
>             at android.app.Activity.setContentView(Activity.java:2267)
>             at com.example.bandhan.myapplication1.Share_Activity.onCreate(Share_Activity.java:15)
>             at android.app.Activity.performCreate(Activity.java:6289)
>             at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
>             at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
>             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2760)
>             at android.app.ActivityThread.access$900(ActivityThread.java:177)
>             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
>             at android.os.Handler.dispatchMessage(Handler.java:102)
>             at android.os.Looper.loop(Looper.java:145)
>             at android.app.ActivityThread.main(ActivityThread.java:5944)
>             at java.lang.reflect.Method.invoke(Native Method)
>             at java.lang.reflect.Method.invoke(Method.java:372)
>             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1389)
>             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)
>      Caused by: null
>             at com.facebook.internal.Validate.sdkInitialized(Validate.java:99)
>             at com.facebook.FacebookSdk.getCallbackRequestCodeOffset(FacebookSdk.java:735)
>             at com.facebook.internal.CallbackManagerImpl$RequestCodeOffset.toRequestCode(CallbackManagerImpl.java:109)
>             at com.facebook.login.widget.LoginButton.<clinit>(LoginButton.java:58)
>             at java.lang.reflect.Constructor.newInstance(Native Method)
>             at java.lang.reflect.Constructor.newInstance(Constructor.java:288)
>             at android.view.LayoutInflater.createView(LayoutInflater.java:614)
>             at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:750)
>             at android.view.LayoutInflater.rInflate(LayoutInflater.java:813)
>             at android.view.LayoutInflater.inflate(LayoutInflater.java:511)
>             at android.view.LayoutInflater.inflate(LayoutInflater.java:415)
>             at android.view.LayoutInflater.inflate(LayoutInflater.java:366)
>             at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:435)
>             at android.app.Activity.setContentView(Activity.java:2267)
>             at com.example.bandhan.myapplication1.Share_Activity.onCreate(Share_Activity.java:15)
>             at android.app.Activity.performCreate(Activity.java:6289)
>             at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
>             at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
>             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2760)
>             at android.app.ActivityThread.access$900(ActivityThread.java:177)
>             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
>             at android.os.Handler.dispatchMessage(Handler.java:102)
>             at android.os.Looper.loop(Looper.java:145)
>             at android.app.ActivityThread.main(ActivityThread.java:5944)
>             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:1389)
>             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)

please help me to solve the problem. Thank you.

Answer 1

If you look at line 99 in Facebook's Validate class, you'll see it's throwing a FacebookSdkNotInitializedException

You need to call FacebookSdk.sdkInitialize(Context) before your LoginButton is loaded (i.e. your call to setContentView())

So, in your Activity's onCreate method:

public void onCreate(Bundle savedInstance){
    super.onCreate(savedInstance);
    FacebookSdk.sdkInitialize(getApplicationContext());
    setContentView(R.layout.my_layout); // Now you can set the layout with the LoginButton
}

Anytime you're going to use Facebook components, you need to ensure that the SDK is initialized.

Also make sure you have the metadata key for your Facebook Application ID in your manifest, else you're going to run into another issue when you try to actually press the LoginButton.