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POWhy is onCreate crashing Android App when I call onClick?
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14370740
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2013-01-17T01:18:47.183
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I'm trying to load a new view when I push a Button. I have a viewPager and the button is on those views. When I call onClick my app never starts, it crashes before anything happens. I've been trying to squash this bug for over a week and I think it's something very amateur. Please help a student programmer! <pre><code>public class Main extends Activity { Button listButton; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); setContentView(R.layout.splash); SplashPager adapter = new SplashPager(); ViewPager myPager = (ViewPager) findViewById(R.id.splashPager); myPager.setAdapter(adapter); myPager.setCurrentItem(0); listButtonListener(); } public void listButtonListener() { listButton = (Button) findViewById(R.id.splashB); listButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { setContentView(R.layout.list_layout); } }); } } </code></pre> Log: <pre><code>01-16 20:09:49.149: W/dalvikvm(29035): threadid=1: thread exiting with uncaught exception (group=0x40207560) 01-16 20:09:49.149: E/AndroidRuntime(29035): FATAL EXCEPTION: main 01-16 20:09:49.149: E/AndroidRuntime(29035): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.survtest2/com.example.survtest2.Main}: java.lang.NullPointerException 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1658) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1674) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:942) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.os.Handler.dispatchMessage(Handler.java:99) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.os.Looper.loop(Looper.java:130) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.main(ActivityThread.java:3733) 01-16 20:09:49.149: E/AndroidRuntime(29035): at java.lang.reflect.Method.invokeNative(Native Method) 01-16 20:09:49.149: E/AndroidRuntime(29035): at java.lang.reflect.Method.invoke(Method.java:507) 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:892) 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:650) 01-16 20:09:49.149: E/AndroidRuntime(29035): at dalvik.system.NativeStart.main(Native Method) 01-16 20:09:49.149: E/AndroidRuntime(29035): Caused by: java.lang.NullPointerException 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.example.survtest2.Main.listButtonListener(Main.java:36) 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.example.survtest2.Main.onCreate(Main.java:30) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1622) 01-16 20:09:49.149: E/AndroidRuntime(29035): ... 11 more 01-16 20:09:49.149: E/AndroidRuntime(29035): [Blue Error Handler] Make Debugging Report file for main 01-16 20:09:49.149: E/AndroidRuntime(29035): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.survtest2/com.example.survtest2.Main}: java.lang.NullPointerException 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1658) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1674) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:942) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.os.Handler.dispatchMessage(Handler.java:99) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.os.Looper.loop(Looper.java:130) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.main(ActivityThread.java:3733) 01-16 20:09:49.149: E/AndroidRuntime(29035): at java.lang.reflect.Method.invokeNative(Native Method) 01-16 20:09:49.149: E/AndroidRuntime(29035): at java.lang.reflect.Method.invoke(Method.java:507) 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:892) 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:650) 01-16 20:09:49.149: E/AndroidRuntime(29035): at dalvik.system.NativeStart.main(Native Method) 01-16 20:09:49.149: E/AndroidRuntime(29035): Caused by: java.lang.NullPointerException 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.example.survtest2.Main.listButtonListener(Main.java:36) 01-16 20:09:49.149: E/AndroidRuntime(29035): at com.example.survtest2.Main.onCreate(Main.java:30) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-16 20:09:49.149: E/AndroidRuntime(29035): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1622) 01-16 20:09:49.149: E/AndroidRuntime(29035): ... 11 more </code></pre> splash.xml: <pre><code><?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <android.support.v4.view.ViewPager android:id="@+id/splashPager" android:layout_width="fill_parent" android:layout_height="fill_parent" > </android.support.v4.view.ViewPager> </LinearLayout> </code></pre> splash2.xml: <pre><code><?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#000000" android:orientation="vertical" > <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:src="@drawable/intro__1" /> <Button android:id="@+id/splashB" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="bottom" android:layout_marginLeft="75dp" android:text="aaaaaaaaaaaaaaaaaa" /> </FrameLayout> </code></pre> ViewPager: <pre><code>@Override public int getCount() { // TODO Auto-generated method stub return 4; } @Override public Object instantiateItem(View collection, int position) { LayoutInflater inflater = (LayoutInflater) collection.getContext() .getSystemService(Context.LAYOUT_INFLATER_SERVICE); int resId = 0; switch (position) { case 0: resId = R.layout.splash2; break; case 1: resId = R.layout.splash3; break; case 2: resId = R.layout.splash4; break; case 3: resId = R.layout.splash5; break; } View view = inflater.inflate(resId, null); ((ViewPager) collection).addView(view, 0); return view; } @Override public void destroyItem(View arg0, int arg1, Object arg2) { // TODO Auto-generated method stub ((ViewPager) arg0).removeView((View) arg2); } @Override public Parcelable saveState() { // TODO Auto-generated method stub return null; } @Override public boolean isViewFromObject(View arg0, Object arg1) { // TODO Auto-generated method stub return arg0 == ((View) arg1); } } </code></pre>
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<java><android><xml><android-viewpager><oncreate>
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Why is onCreate crashing Android App when I call onClick?
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