Android Nullpointer exception button

Question

my app sometime crashes, i know where but i don't know why. Please watch this code:

private Button btFacebook     
@Override   
public final void onCreate(Bundle savedInstanceState) 
{
    ....
    btFacebook     = (Button) findViewById(R.id.bt_fb_zaloguj);
    btFacebook.setText(getResources().getString(R.string.act_logowanie_bt_facebook).toUpperCase()); //line crash 
    .... 
}

Why btFacebook sometime is null?

EDIT:

> java.lang.RuntimeException: Unable to start activity ComponentInfo{pl.gosell.ghmaster/pl.gosell.ghmaster.activity.ActSplash}: java.lang.NullPointerException
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305)
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2363)
android.app.ActivityThread.access$900(ActivityThread.java:161)
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1265)
android.os.Handler.dispatchMessage(Handler.java:102)
android.os.Looper.loop(Looper.java:157)
android.app.ActivityThread.main(ActivityThread.java:5356)8at java.lang.reflect.Method.invokeNative(Native Method)
java.lang.reflect.Method.invoke(Method.java:515)
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
pl.gosell.ghmaster.activity.ActSplash.onActivityData(ActSplash.java:184)
com.android.lifter.activity.ActivityBase.onCreate(ActivityBase.java:99)
android.app.Activity.performCreate(Activity.java:5426)
android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2269)
19... 11 more

If your application is crashing on the loading, it might me because of the above, if it's crashing after loading, it means whatever functionality that button is doing is causing the crash. Only way to answer this is if you post the logcat of the error, otherwise people are giving answers blindly. — NightwareSystems
– NightwareSystems, Commented Oct 3, 2014 at 9:15

M D · Accepted Answer · 2014-10-03 07:26:35Z

2

You missed

  setContentView(R.layout.your_layout);

and then you initialized button like:

protected  void onCreate(Bundle savedInstanceState) 
{
super.onCreate(savedInstanceState);
setContentView(R.layout.your_layout);
btFacebook     = (Button) findViewById(R.id.bt_fb_zaloguj);
btFacebook.setText(getResources().getString(R.string.act_logowanie_bt_facebook).toUpperCase());      //line crash 
.... 
}

edited Oct 3, 2014 at 7:26

answered Oct 3, 2014 at 7:19

M D

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2 Comments

user3284206 Over a year ago

Thank you for reply, but i don't missed setContentView(R.layout.your_layout);

M D Over a year ago

@michael It's totally fake that you said my app sometime crashes

Piyush · Accepted Answer · 2014-10-03 07:24:55Z

1

Looking at your code if u missed this.

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

then add it

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    btFacebook = (Button) findViewById(R.id.bt_fb_zaloguj);
    btFacebook.setText(getResources().getString(R.string.act_logowanie_bt_facebook).toUpperCase());

answered Oct 3, 2014 at 7:24

Piyush

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1 Comment

user3284206 Over a year ago

Thank you for reply, but i don't missed super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);

Sumit Sahoo · Accepted Answer · 2014-10-03 07:28:26Z

-1

If you are already in Activity you can simplify you call like this

this.getString(R.string.act_logowanie_bt_facebook)

Also if string is there it should not give exception. I think the exception you are getting is because of Button. Somehow button object is null. Can you have a look at your view and check if the id is same ?

answered Oct 3, 2014 at 7:28

Sumit Sahoo

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