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POUnable to start activity ComponentInfo{..} : java.lang.NullPointerException
 

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  1. POUnable to start activity ComponentInfo{..} : java.lang.NullPointerException
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    <p>I'm trying to start a new activity when the Button playlistBtn is clicked, and I'm getting a NullPointerException, but I can't see where did I go wrong with my references.</p> <p>Complete error log:</p> <pre><code>04-08 17:02:07.847: E/AndroidRuntime(5869): FATAL EXCEPTION: main 04-08 17:02:07.847: E/AndroidRuntime(5869): java.lang.RuntimeException: Unable to start activity ComponentInfo{app.and.androidmusic/app.and.androidmusic.PlaylistActivity}: java.lang.NullPointerException 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.ActivityThread.access$600(ActivityThread.java:141) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.os.Handler.dispatchMessage(Handler.java:99) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.os.Looper.loop(Looper.java:137) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.ActivityThread.main(ActivityThread.java:5039) 04-08 17:02:07.847: E/AndroidRuntime(5869): at java.lang.reflect.Method.invokeNative(Native Method) 04-08 17:02:07.847: E/AndroidRuntime(5869): at java.lang.reflect.Method.invoke(Method.java:511) 04-08 17:02:07.847: E/AndroidRuntime(5869): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 04-08 17:02:07.847: E/AndroidRuntime(5869): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 04-08 17:02:07.847: E/AndroidRuntime(5869): at dalvik.system.NativeStart.main(Native Method) 04-08 17:02:07.847: E/AndroidRuntime(5869): Caused by: java.lang.NullPointerException 04-08 17:02:07.847: E/AndroidRuntime(5869): at app.and.androidmusic.PlaylistActivity.onCreate(PlaylistActivity.java:68) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.Activity.performCreate(Activity.java:5104) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 04-08 17:02:07.847: E/AndroidRuntime(5869): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) </code></pre> <p>MainActivity.java:</p> <pre><code> public class MainActivity extends ListActivity { ... protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); ... Button btnPlaylist = (Button) findViewById(R.id.playlistBtn); btnPlaylist.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View arg0) { Intent in = new Intent(getApplicationContext(), PlaylistActivity.class); startActivity(in); </code></pre> <p>PlaylistActivity.java:</p> <pre><code>public class PlaylistActivity extends ListActivity{ ... @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_playlist); { </code></pre> <p>AndroidManifest.xml:</p> <pre><code>&lt;activity android:name="app.and.androidmusic.MainActivity" android:label="@string/app_name" &gt; &lt;intent-filter&gt; &lt;action android:name="android.intent.action.MAIN" /&gt; &lt;category android:name="android.intent.category.LAUNCHER" /&gt; &lt;/intent-filter&gt; &lt;/activity&gt; &lt;activity android:name=".PlaylistActivity" /&gt; </code></pre> <p>Ok, so here is activity_main.xml as you asked it's quite long:</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" tools:context=".MainActivity" &gt; &lt;app.and.androidmusic.DragNDropListView android:id="@+id/android:list" android:layout_width="match_parent" android:layout_height="300dp" android:layout_below="@+id/playlistBtn" android:layout_alignParentLeft="true" &gt; &lt;/app.and.androidmusic.DragNDropListView&gt; &lt;Button android:id="@+id/playBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/android:list" android:layout_toRightOf="@+id/prevBtn" android:text="@string/playBtn" /&gt; &lt;Button android:id="@+id/pauseBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/android:list" android:layout_toRightOf="@+id/playBtn" android:text="@string/pauseBtn" /&gt; &lt;Button android:id="@+id/prevBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/android:list" android:text="@string/prevBtn" /&gt; &lt;Button android:id="@+id/nextBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/android:list" android:layout_toRightOf="@+id/pauseBtn" android:text="@string/nextBtn" /&gt; &lt;Button android:id="@+id/songsBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/songTxt" android:text="@string/songsBtn" /&gt; &lt;Button android:id="@+id/playlistBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/songTxt" android:layout_toRightOf="@+id/songsBtn" android:text="@string/playlistBtn" /&gt; &lt;Button android:id="@+id/eqBtn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/songTxt" android:layout_toRightOf="@+id/playlistBtn" android:text="@string/eqBtn" /&gt; &lt;TextView android:id="@+id/songTxt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:text="" /&gt; &lt;/RelativeLayout&gt; </code></pre>
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    1. PTQuestion
    1. USuser1477362
    1. USuser1477362
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    1. COPleaes put a better title on your question.
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      1. POUnable to start activity ComponentInfo{..} : java.lang.NullPointerException
      1. USRobert Harvey
    2. COPlease post the full stack trace for the error.
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      1. POUnable to start activity ComponentInfo{..} : java.lang.NullPointerException
      1. USthegrinner
    3. COplz also add xml of activity_main layout with question
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      1. POUnable to start activity ComponentInfo{..} : java.lang.NullPointerException
      1. USρяσѕρєя K
 

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