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POAndroid - NullPointerException on ViewPager
 

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  1. POAndroid - NullPointerException on ViewPager
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    <p>I am trying to create dialog with fragment but when I call the setAdapter method I have a Java NullPointerException, and I can't find the error. </p> <p>Java Code:</p> <pre><code>public class MainActivity extends FragmentActivity { Context myContext; private MyAdapter mAdapter; private ViewPager mPager; String TAG = "Dialog"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); myContext = this; findViewById(R.id.button1).setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { final Dialog dialog = new Dialog(myContext); dialog.setContentView(R.layout.layout_dialog); mAdapter = new MyAdapter(getSupportFragmentManager()); mPager = (ViewPager) dialog.findViewById(R.id.myViewPager); **mPager.setAdapter(mAdapter);** //Line 39, the error is on this line. dialog.show(); } }); } public class MyAdapter extends FragmentPagerAdapter { int counts; public MyAdapter(FragmentManager fm) { super(fm); } @Override public int getCount() { return 3; } @Override public Fragment getItem(int position) { switch (position) { case 0: return new ImageFragment(R.drawable.icecream); case 1: return new ImageFragment(R.drawable.cupcake); case 2: return new ImageFragment(R.drawable.donut); default: return null; } } } } </code></pre> <p>Fragment class:</p> <pre><code>public class ImageFragment extends Fragment { private final int imageResourceId; public ImageFragment(int imageResourceId) { this.imageResourceId = imageResourceId; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.activity_dialog_item, container, false); ImageView imageView = (ImageView) view.findViewById(R.id.imageView1); imageView.setImageResource(imageResourceId); return view; } </code></pre> <p>}</p> <p>activity_main xml code:</p> <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent"&gt; &lt;Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_marginRight="20dip" android:layout_marginTop="30dip" android:text="Show Dialog" /&gt; &lt;/RelativeLayout&gt; </code></pre> <p>layout_dialog.xml code:</p> <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" &gt; &lt;android.support.v4.view.ViewPager android:id="@+id/myViewPager" android:layout_width="match_parent" android:layout_height="match_parent" /&gt; &lt;/LinearLayout&gt; </code></pre> <p>activity_dialog_item.xml code:</p> <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" &gt; &lt;ImageView android:id="@+id/imageView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:src="@drawable/cupcake" /&gt; &lt;/RelativeLayout&gt; </code></pre> <p>Error:</p> <pre><code>03-06 13:58:22.546: E/AndroidRuntime(818): FATAL EXCEPTION: main 03-06 13:58:22.546: E/AndroidRuntime(818): java.lang.NullPointerException 03-06 13:58:22.546: E/AndroidRuntime(818): at com.example.viewpager.MainActivity$1.onClick(MainActivity.java:39) 03-06 13:58:22.546: E/AndroidRuntime(818): at android.view.View.performClick(View.java:2485) 03-06 13:58:22.546: E/AndroidRuntime(818): at android.view.View$PerformClick.run(View.java:9080) 03-06 13:58:22.546: E/AndroidRuntime(818): at android.os.Handler.handleCallback(Handler.java:587) 03-06 13:58:22.546: E/AndroidRuntime(818): at android.os.Handler.dispatchMessage(Handler.java:92) 03-06 13:58:22.546: E/AndroidRuntime(818): at android.os.Looper.loop(Looper.java:123) 03-06 13:58:22.546: E/AndroidRuntime(818): at android.app.ActivityThread.main(ActivityThread.java:3683) 03-06 13:58:22.546: E/AndroidRuntime(818): at java.lang.reflect.Method.invokeNative(Native Method) 03-06 13:58:22.546: E/AndroidRuntime(818): at java.lang.reflect.Method.invoke(Method.java:507) 03-06 13:58:22.546: E/AndroidRuntime(818): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 03-06 13:58:22.546: E/AndroidRuntime(818): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 03-06 13:58:22.546: E/AndroidRuntime(818): at dalvik.system.NativeStart.main(Native Method) </code></pre>
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    1. PTQuestion
    1. USMansi
    1. USMansi
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    1. This table or related slice is empty.
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      1. POAndroid - NullPointerException on ViewPager
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      1. VTUpMod
    1. COYou *could* point out row 39 of MainActivity.java. Then, try to figure out what, on that row, could be null - and why. =)
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      1. POAndroid - NullPointerException on ViewPager
      1. USJ. Steen
    2. COwhat is at line 39 on `MainActivity.java`?
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      1. POAndroid - NullPointerException on ViewPager
      1. USPraful Bhatnagar
    3. COi have edit my question and point out line 39
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      1. POAndroid - NullPointerException on ViewPager
      1. USMansi
 

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