contentProvider构造Cursor实例
public class MyProvider extends ContentProvider {

final static String TABLE_NAME = "test";

@Override
public int delete(Uri arg0, String arg1, String[] arg2) {
// TODO Auto-generated method stub
return 0;
}

@Override
public String getType(Uri arg0) {
// TODO Auto-generated method stub
return null;
}

@Override
public Uri insert(Uri arg0, ContentValues arg1) {
// TODO Auto-generated method stub


return null;
}

@Override
public boolean onCreate() {
// TODO Auto-generated method stub
return false;
}

@Override
public Cursor query(Uri arg0, String[] arg1, String arg2, String[] arg3,
String arg4) {
// TODO Auto-generated method stub
//Cursor cur = mdbHelper.getWritableDatabase().rawQuery("select * from todo_table", null);
ToDoDB mdbHelper;
//Cursor cur2 = mdbHelper.test();
//return cur2;
//////////////////////////////////////
String content;

try {
/*
File file= new File("/sdcard/qq.txt");
FileInputStream in = new FileInputStream(file);
int length = (int) file.length();
byte[] buffer = new byte[length];
in.read(buffer, 0, length);
content = EncodingUtils.getString(buffer, "UTF-8");
in.close();*/

String[] columns = new String[] { "MyUser.User._ID", "MyUser.User.USER_NAME" };
MatrixCursor cur = new MatrixCursor(columns);
String[] values = new String[] { "0", "content" };
cur.moveToFirst();
cur.addRow(values);
return cur;
} catch (Exception e) {
return null;
}
}

@Override
public int update(Uri arg0, ContentValues arg1, String arg2, String[] arg3) {
// TODO Auto-generated method stub
return 0;
}

}