android - 如何正确执行托管查询？

Question

我正在针对 API 11 进行开发，所以我认为没有必要使用LoadCursor.

我有三个类：MainActivity extends Activity、Columns extends PagerAdapter和GetMp3Tag

MainActivity

miAdapter = new Columns ();
columnas = (ViewPager) findViewById(R.id.columnas);
columnas.setAdapter(miAdapter);

Columns

GetMP3Tag MP3TAG = new GetMP3Tag();
MP3TAG.GetCount(types_ID.ALL_ARTIST);

GetMp3Tag

public String GetCount(types_ID Type_First) {
    Cursor cursor;
    cursor = managedQuery(Path_Normal, STAR , audioselection, null, null);
}

日志猫

FATAL EXCEPTION: main
java.lang.NullPointerException at android.content.ContextWrapper.getContentResolver(ContextWrapper.java:99)