title: get current user email that is logged
body: <p>I am using firebase to do the authentication in my application, and everything works fine, but when i log in i want to display the user email that is logged in, and what i did crashes the application when i run it, so i did this:</p>
  
  <pre><code> auth = FirebaseAuth.getInstance();
    userTxt.setText(auth.getCurrentUser().getEmail().toString());
  </code></pre>
  
  <p>i defined a auth object and then used that auth to get the current user email, after that all in one line i passed that to my textView, what am i doing wrong here?</p>
  
  <p><strong>StackTrace</strong></p>
  
  <pre><code>04-09 09:00:11.247 2987-2987/com.esmad.pdm.friendlymanager E/AndroidRuntime: FATAL EXCEPTION: main
                                                                               Process: com.esmad.pdm.friendlymanager, PID: 2987
                                                                               java.lang.RuntimeException: Unable to start activity ComponentInfo{com.esmad.pdm.friendlymanager/com.esmad.pdm.friendlymanager.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.auth.FirebaseUser com.google.firebase.auth.FirebaseAuth.getCurrentUser()' on a null object reference
                                                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
                                                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
                                                                                   at android.app.ActivityThread.access$800(ActivityThread.java:151)
                                                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                   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)
                                                                                Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'com.google.firebase.auth.FirebaseUser com.google.firebase.auth.FirebaseAuth.getCurrentUser()' on a null object reference
                                                                                   at com.esmad.pdm.friendlymanager.MainActivity.onCreate(MainActivity.java:34)
                                                                                   at android.app.Activity.performCreate(Activity.java:5990)
                                                                                   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
                                                                                   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
                                                                                   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
                                                                                   at android.app.ActivityThread.access$800(ActivityThread.java:151) 
                                                                                   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                                   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) 
  </code></pre>