Tukukkk

Basically i have three buttons on viewpager's page 1 . and i want to select one of them and get the value into my db. but when i am clicking on any of the button it is showing me an error:

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.example.itsandpro.Signup.PreferenceActivity.onCreate(PreferenceActivity.java:88)
at android.app.Activity.performCreate(Activity.java:6679)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)

and my code for button at viewpager is:

myViewPagerAdapter = new MyViewPagerAdapter();
viewPager.setAdapter(myViewPagerAdapter);

    weightloss=findViewById(R.id.reduceweight);

    maintainweight=findViewById(R.id.controlthecalories);

    gainweight=findViewById(R.id.goodphysique);



    weightloss.setOnClickListener(new View.OnClickListener() {

        @SuppressLint("ShowToast")

        @Override

        public void onClick(View v) {

            Toast.makeText(getApplicationContext(),"it worked",Toast.LENGTH_LONG);

        }

    });

what i need is to select the button but i am unable to do that.

According to reference at com.example.itsandpro.Signup.PreferenceActivity.onCreate(PreferenceActivity.java:88) you set your OnClickListener in your Activity which is not noticeable in your pasted code.

When you're using a ViewPager you are also using Fragments.

Activity

• 
  

  ViewPager

  
  
  
  
  
  • Fragment 1
  
  
  • Fragment 2
  
  
  • Fragment 3
  
  
  
  

If you want to add a click listener of a button which is on Fragment 1 (Basically i have three buttons on viewpager's page 1) you have to register the click Listener in your Fragment and not in your Activity because the layout of your activity don't contain this buttons.

If i'm wrong, please update your question with the code of your activity, the layout of your activity and the code of your first fragment plus viewpager.