android 多個cursor 的讀取 和讀取某個Cursor其他從集合中擷取的速度比較

如代碼所示，2的速度明顯快好幾倍

public void getContact(Context con){
Cursor cursor=con.getContentResolver().query(ContactsContract.Contacts.CONTENT_URI,
PROJECTION,null,null, QUERY_ORDER_BY_NAME);
if (cursor != null) {
try {
List<UContact> uContacts = new ArrayList<UContact>();
if (cursor.moveToFirst()) {
do {
UContact item = new UContact();
item.setId(cursor.getLong(0));
item.setPhotoId(cursor.getLong(1));
item.setName(cursor.getString(2));
item.setFirstChar(getFirstChar(cursor
.getString(android.os.Build.VERSION.SDK_INT >= 8 ? 3
: 2)));
if (android.os.Build.VERSION.SDK_INT >= 8)
item.setSortKey(cursor.getString(3));
queryUMGroupById(con,item, item.getId());
uContacts.add(item);
} while (cursor.moveToNext());
}
Collections.sort(uContacts, new ArrayCompare());
isContactChange = false;
// mContactCount.put(0, uContacts.size());
} catch (Exception e) {
e.printStackTrace();
} finally {
cursor.close();
cursor = null;
}
}
}

private void queryUMGroupById(Context con,UContact contact, long id) {
int groupId=0;
Cursor cursor=con.getContentResolver().query(ContactsContract.Data.CONTENT_URI, new String[] { CommonDataKinds.GroupMembership.GROUP_ROW_ID }
, Data.CONTACT_ID + " = ? AND " + Data.MIMETYPE + " =?",
new String[] { String.valueOf(id), UM_GROUP_MIMETYPE }, null);

if(cursor!=null){
int count=cursor.getCount();
if(count>0){
cursor.moveToFirst();
groupId=  cursor.getInt(0);
contact.setUmGroupId(groupId);
if(cursor!=null){
cursor.close();
cursor=null;
}

}
}
}


public void getContact2(Context con){
Cursor cursor_group=con.getContentResolver().query(ContactsContract.Data.CONTENT_URI, 
new String[] {Data.CONTACT_ID,CommonDataKinds.GroupMembership.GROUP_ROW_ID }
, Data.MIMETYPE + " =?",
new String[] {UM_GROUP_MIMETYPE }, null);

if(cursor_group!=null){
mGroupMap.clear();
int count=cursor_group.getCount();
if(count>0){
cursor_group.moveToFirst();
for(int i=0;i<count;i++){
int contactId=cursor_group.getInt(0);
int groupId=cursor_group.getInt(1);
mGroupMap.put(contactId, groupId);
cursor_group.moveToNext();
}
if(cursor_group!=null){
cursor_group.close();
cursor_group=null;
}
}
}


Cursor cursor=con.getContentResolver().query(ContactsContract.Contacts.CONTENT_URI, PROJECTION,null,null, QUERY_ORDER_BY_NAME);
if (cursor != null) {
try {
List<UContact> uContacts = new ArrayList<UContact>();
if (cursor.moveToFirst()) {
do {
UContact item = new UContact();
item.setId(cursor.getLong(0));
item.setPhotoId(cursor.getLong(1));
item.setName(cursor.getString(2));
item.setFirstChar(getFirstChar(cursor
.getString(android.os.Build.VERSION.SDK_INT >= 8 ? 3
: 2)));
if (android.os.Build.VERSION.SDK_INT >= 8)
item.setSortKey(cursor.getString(3));
item.setUmGroupId(mGroupMap.get(item.getId()));
uContacts.add(item);
} while (cursor.moveToNext());
}
Collections.sort(uContacts, new ArrayCompare());
isContactChange = false;
// mContactCount.put(0, uContacts.size());
} catch (Exception e) {
e.printStackTrace();
} finally {
cursor.close();
cursor = null;
}
}
}