У меня есть сетчатый вид альбомов внутри фрейма viewpager. Идея состоит в том, чтобы отобразить содержимое альбома в новом окне при нажатии на элемент сетки. Вот мой код:Почему активность не создается?
Внутри onCreateView() метод Albums фрагмента:
GridView grid = (GridView) getView().findViewById(R.id.grid);
grid.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
TextView al = (TextView) view.findViewById(R.id.album_name);
TextView ar = (TextView) view.findViewById(R.id.songs_num);
String album_name = (String) al.getText();
String artist_name = (String) ar.getText();
startActivity(new Intent(getActivity().getApplicationContext(), DisplayAlbumContent.class).putExtra("pos", position).putExtra("album_name", album_name).putExtra("artist_name", artist_name));
}
});
Вот DisplayAlbumContent.java:
public class DisplayAlbumContent extends Activity implements LoaderManager.LoaderCallbacks<Cursor>{
DisplaySongsAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.album_detail);
}
Intent i = getIntent();
Bundle b = i.getExtras();
String val[] = {(String) b.getCharSequence("album_name")};
static final String[] ALBUM_DETAIL_PROJECTION = { MediaStore.Audio.Media._ID,MediaStore.Audio.Media.ALBUM_ID, MediaStore.Audio.Media.TITLE, MediaStore.Audio.Media.ARTIST, MediaStore.Audio.Media.DURATION};
String where = MediaStore.Audio.Media.ALBUM + "=?";
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
String orderby = MediaStore.Audio.Media.TITLE;
return new CursorLoader(this, MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,ALBUM_DETAIL_PROJECTION, where, val, orderby);
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
mAdapter.swapCursor(data);
}
public void onLoaderReset(Loader<Cursor> loader) {
mAdapter.swapCursor(null);
}
}
Однако я получаю следующее сообщение об ошибке:
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.tekinarslan.material.sample/com.screens.DisplayAlbumContent}: java.lang.NullPointerException
at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2264)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.screens.DisplayAlbumContent.<init>(DisplayAlbumContent.java:29)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1215)
at android.app.Instrumentation.newActivity(Instrumentation.java:1061)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2255)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
at android.os.Handler.dispatchMessage(Handler.java:110)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
at dalvik.system.NativeStart.main(Native Method)
Поскольку есть NullPointerException в строке 29 класса DisplayAlbumContent, пожалуйста, после того, что есть в номере строки 29 – nvinayshetty