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POListView of audio files on android
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copied!<p>I'm trying to gather all audio files on a device external source. When I run on device I get a message that says Unfortanately "" has stopped. I have yet to be able to find where the problem persists. Ive looked online and found multiple examples that do it exactly like this and nothing will work.</p> <pre><code> package com.example.djraspi; import java.util.ArrayList; import java.util.List; import android.os.Bundle; import android.provider.MediaStore; import android.app.ListActivity; import android.view.Menu; import android.widget.ArrayAdapter; import android.widget.ListView; import android.database.Cursor; public class MainActivity extends ListActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initMusicList(); } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } private void initMusicList(){ String selection = MediaStore.Audio.Media.IS_MUSIC + " !=0"; String[] projection = { MediaStore.Audio.Media._ID, MediaStore.Audio.Media.ARTIST_ID, MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.DATA, MediaStore.Audio.Media.DISPLAY_NAME, MediaStore.Audio.Media.DURATION }; Cursor cursor = getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, projection, selection, null, null); List<String> songList = new ArrayList<String>(); while(cursor.moveToNext()){ songList.add(cursor.getString(0) + "||" + cursor.getString(1) + "||" + cursor.getString(2) + "||" + cursor.getString(3) + "||" + cursor.getString(4) + "||" + cursor.getString(5) + "||" + cursor.getString(6)); } this.setListAdapter(new ArrayAdapter<String>(this, R.layout.activity_main, android.R.id.list, songList)); } } </code></pre> <p>Here is my activity_main</p> <pre><code> <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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <ListView android:id="@android:id/list" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_marginTop="20dp"/> </RelativeLayout> </code></pre> <p>Here is my logCat file that I get:</p> <pre><code>10-23 12:35:44.093: I/Process(8677): Sending signal. PID: 8677 SIG: 9 10-23 12:36:42.131: E/Trace(8837): error opening trace file: No such file or directory (2) 10-23 12:36:42.264: D/AndroidRuntime(8837): Shutting down VM 10-23 12:36:42.264: W/dalvikvm(8837): threadid=1: thread exiting with uncaught exception (group=0x40dbf2a0) 10-23 12:36:42.303: E/AndroidRuntime(8837): FATAL EXCEPTION: main 10-23 12:36:42.303: E/AndroidRuntime(8837): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.djraspi/com.example.djraspi.MainActivity}: java.lang.NullPointerException 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2136) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2174) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.ActivityThread.access$700(ActivityThread.java:141) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1267) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.os.Handler.dispatchMessage(Handler.java:99) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.os.Looper.loop(Looper.java:137) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.ActivityThread.main(ActivityThread.java:5059) 10-23 12:36:42.303: E/AndroidRuntime(8837): at java.lang.reflect.Method.invokeNative(Native Method) 10-23 12:36:42.303: E/AndroidRuntime(8837): at java.lang.reflect.Method.invoke(Method.java:511) 10-23 12:36:42.303: E/AndroidRuntime(8837): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792) 10-23 12:36:42.303: E/AndroidRuntime(8837): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555) 10-23 12:36:42.303: E/AndroidRuntime(8837): at dalvik.system.NativeStart.main(Native Method) 10-23 12:36:42.303: E/AndroidRuntime(8837): Caused by: java.lang.NullPointerException 10-23 12:36:42.303: E/AndroidRuntime(8837): at com.example.djraspi.MainActivity.initMusicList(MainActivity.java:43) 10-23 12:36:42.303: E/AndroidRuntime(8837): at com.example.djraspi.MainActivity.onCreate(MainActivity.java:21) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.Activity.performCreate(Activity.java:5058) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 10-23 12:36:42.303: E/AndroidRuntime(8837): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100) 10-23 12:36:42.303: E/AndroidRuntime(8837): ... 11 more 10-23 12:41:48.053: E/Trace(9081): error opening trace file: No such file or directory (2) 10-23 12:41:48.467: D/AndroidRuntime(9081): Shutting down VM 10-23 12:41:48.467: W/dalvikvm(9081): threadid=1: thread exiting with uncaught exception (group=0x40dbf2a0) 10-23 12:41:48.467: E/AndroidRuntime(9081): FATAL EXCEPTION: main 10-23 12:41:48.467: E/AndroidRuntime(9081): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.djraspi/com.example.djraspi.MainActivity}: java.lang.NullPointerException 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2136) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2174) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.ActivityThread.access$700(ActivityThread.java:141) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1267) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.os.Handler.dispatchMessage(Handler.java:99) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.os.Looper.loop(Looper.java:137) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.ActivityThread.main(ActivityThread.java:5059) 10-23 12:41:48.467: E/AndroidRuntime(9081): at java.lang.reflect.Method.invokeNative(Native Method) 10-23 12:41:48.467: E/AndroidRuntime(9081): at java.lang.reflect.Method.invoke(Method.java:511) 10-23 12:41:48.467: E/AndroidRuntime(9081): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792) 10-23 12:41:48.467: E/AndroidRuntime(9081): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555) 10-23 12:41:48.467: E/AndroidRuntime(9081): at dalvik.system.NativeStart.main(Native Method) 10-23 12:41:48.467: E/AndroidRuntime(9081): Caused by: java.lang.NullPointerException 10-23 12:41:48.467: E/AndroidRuntime(9081): at com.example.djraspi.MainActivity.initMusicList(MainActivity.java:43) 10-23 12:41:48.467: E/AndroidRuntime(9081): at com.example.djraspi.MainActivity.onCreate(MainActivity.java:21) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.Activity.performCreate(Activity.java:5058) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 10-23 12:41:48.467: E/AndroidRuntime(9081): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100) 10-23 12:41:48.467: E/AndroidRuntime(9081): ... 11 more </code></pre>

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