CODEWITHSUNDEEP
androidandroid-fragmentsandroid-viewpager
user3153020
user3153020

Reputation: 37

NullPointer exception on setAdapter for Viewpager

In a one screen I am using two viewPagers - one for image autoscroling and other for buttons hand scrolling. Image autoscrolling was working perfectly fine, but when I added implementation for buttons on viewPager, my application started crashing for nullpointer on setAdapter, I am using fragmentPagerAdapter. For images autoslider I am using this reference code by https://github.com/JakeWharton/Android-ViewPagerIndicator

Here is my source code

layout xml file simple_circles.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <!-- android:layout_weight="0.01" -->

    <SearchView
        android:id="@+id/search_view"
        android:layout_width="fill_parent"
        android:layout_height="80dp" >
    </SearchView>
    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="fill_parent"
        android:layout_height="400dp">
    </android.support.v4.view.ViewPager>

    <android.support.v4.view.ViewPager
        android:id="@+id/pager_for_buttons"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >       

    </android.support.v4.view.ViewPager>

fragment for adding buttons on slider -

    public class ScreenSlidePageFragment extends Fragment {

    public static final String ARG_PAGE = "page";


    private int mPageNumber;


    public static Fragment create(int pageNumber) {
        ScreenSlidePageFragment fragment = new ScreenSlidePageFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_PAGE, pageNumber);
        fragment.setArguments(args);
        return fragment;
    }

    public ScreenSlidePageFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mPageNumber = getArguments().getInt(ARG_PAGE);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
         // Inflate the layout containing a title and body text.
        Button music_button = new Button(getActivity());
        music_button.setText("Music");

        Button news_button = new Button(getActivity());
        news_button.setText("News");

        Button videos_button = new Button(getActivity());
        videos_button.setText("Videos");
        Button photos_button = new Button(getActivity());
        photos_button.setText("Photos");
        LinearLayout layout = new LinearLayout(getActivity());
        layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        //layout.setGravity(Gravity.CENTER);
        layout.addView(music_button);
        layout.addView(news_button);
        layout.addView(videos_button);
        layout.addView(photos_button);

        return layout;



    }


    public int getPageNumber() {
        return mPageNumber;
    }
}

Activity class and adapter for viewPager - 

public class SampleCirclesDefault extends FragmentActivity {

    // Initialization

    TestFragmentAdapter mAdapter;
    ViewPager mPager;
    PageIndicator mIndicator;
    Bitmap bitmap;
    ArrayList<String> bandImagesList;
    ImageView build_bandapp_img;
    boolean pagerMoved;
    Runnable Update;
    Handler h;
    long ANIM_VIEWPAGER_DELAY;
    Handler handler;
    int NUM_PAGES = 5;
    ViewPager buttonPager;
    ScreenSlidePagerAdapter buttonAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // No action bar
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
            **setContentView(R.layout.simple_circles);**
        build_bandapp_img = (ImageView) findViewById(R.id.imageView_for_webview);
        build_bandapp_img.setOnClickListener(new OnClickListener() {
            // Build bandapp button
            @Override
            public void onClick(View v) {

                Intent i = new Intent(SampleCirclesDefault.this,
                        BandDetailedActivity.class);
                startActivity(i);
            }
        });

        mAdapter = new TestFragmentAdapter(getSupportFragmentManager());// adapter
                                                                        // for
                                                                        // viewpager

        mPager = (ViewPager) findViewById(R.id.pager);
        mPager.setAdapter(mAdapter);
        buttonAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
        //buttonAdapter = new AdapterForFragmentOfButtonSlider(getSupportFragmentManager());
        buttonPager = (ViewPager)findViewById(R.id.pager_for_buttons);
        buttonPager.setAdapter(buttonAdapter); //***error -NullPointerException***//

        mIndicator = (CirclePageIndicator) findViewById(R.id.indicator);
        mIndicator.setViewPager(mPager);// dot dot indicator
        buttonPager.setCurrentItem(1); 
        handler = new Handler();
        // autoscrolling of view pager
        Update = new Runnable() {

            int currentPage = mPager.getCurrentItem();

            public void run() {
                if (currentPage == NUM_PAGES - 1) {
                    currentPage = 0;
                }
                mPager.setCurrentItem(currentPage++, true);
            }
        };

        Timer swipeTimer = new Timer();
        swipeTimer.schedule(new TimerTask() {

            @Override
            public void run() {
                handler.post(Update);
            }
        }, 100, 5000);

    }

     private class ScreenSlidePagerAdapter extends FragmentPagerAdapter {
            public ScreenSlidePagerAdapter(FragmentManager fragmentManager) {
                super(fragmentManager);
            }

            @Override
            public Fragment getItem(int position) {
                return ScreenSlidePageFragment.create(position);
            }

            @Override
            public int getCount() {
                return NUM_PAGES;
            }
        }
    }

Stack trace 

01-23 13:56:57.067: W/dalvikvm(18861): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
01-23 13:56:57.098: E/AndroidRuntime(18861): FATAL EXCEPTION: main
01-23 13:56:57.098: E/AndroidRuntime(18861): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.viewpagerindicator.sample/com.viewpagerindicator.sample.SampleCirclesDefault}: java.lang.NullPointerException
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.os.Looper.loop(Looper.java:137)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.ActivityThread.main(ActivityThread.java:5041)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at java.lang.reflect.Method.invokeNative(Native Method)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at java.lang.reflect.Method.invoke(Method.java:511)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at dalvik.system.NativeStart.main(Native Method)
01-23 13:56:57.098: E/AndroidRuntime(18861): Caused by: java.lang.NullPointerException
01-23 13:56:57.098: E/AndroidRuntime(18861):    at com.viewpagerindicator.sample.SampleCirclesDefault.onCreate(SampleCirclesDefault.java:85)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.Activity.performCreate(Activity.java:5104)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-23 13:56:57.098: E/AndroidRuntime(18861):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-23 13:56:57.098: E/AndroidRuntime(18861):    ... 11 more
01-23 13:57:13.356: I/Process(18861): Sending signal. PID: 18861 SIG: 9

I have pointed exactly where I am getting error.

Please help me to resolve this error, thanks in advance.

Upvotes: 3

Views: 6655

Answers (1)

Raghunandan
Raghunandan

Reputation: 133570

yes it was because of different layout files

So if buttonPager is null you have set a layout that does not have a buttonPager.

This confirms what i had commented earlier.

  buttonPager = (ViewPager)findViewById(R.id.pager_for_buttons);
  buttonPager.setAdapter(buttonAdapter);

Also check this

http://developer.android.com/training/animation/screen-slide.html

Upvotes: 1

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