优化数以千计的SQLite的查询的android(Optimise thousands of SQL

我有这样的任务，我需要查询有关每个联系人的所有信息，并对其进行备份。

第一触点770占用5-6秒，同时后770个触头，每个触头需要超过一秒查询所有数据加载。 我明白，这是一个复杂的查询，但说实在是太慢了。 有什么办法来优化呢？

码

// This contacts array typically contains more than a thousand items in it, even more
contacts.forEach {
val lookupKey = it.lookupKey
queryContacts(lookupKey)
}

fun queryContacts(lookupKey: String) {
    val contact = Contact()
    val contactsCursor = resolver.query(CONTENT_URI, arrayOf(_ID, DISPLAY_NAME, HAS_PHONE_NUMBER), CONTACTS_ALL_DETAILS_SELECTION, arrayOf(lookupKey), null)

    if (contactsCursor.count > 0) {

        while (contactsCursor.moveToNext()) {

            val contactId = contactsCursor.getString(contactsCursor.getColumnIndex(_ID))
            val name = contactsCursor.getString(contactsCursor.getColumnIndex(DISPLAY_NAME))
            contact.name = name

            val hasPhoneNumber = Integer.parseInt(contactsCursor.getString(contactsCursor.getColumnIndex(HAS_PHONE_NUMBER)))

            // This is to read all phone numbers associated with the contact
            val phoneNumbers = arrayListOf<String>()
            if (hasPhoneNumber > 0) {
                val phoneCursor = contentResolver.query(PHONE_CONTENT_URI, null, "$PHONE_CONTACT_ID = ?", arrayOf(contactId), null)
                while (phoneCursor.moveToNext()) {
                    phoneNumbers.add(phoneCursor.getString(phoneCursor.getColumnIndex(NUMBER)))
                }
                phoneCursor.close()
            }
            contact.phoneNumbers.addAll(phoneNumbers)

            // Read every email id associated with the contact
            val emailCursor = contentResolver.query(EMAIL_CONTENT_URI, null, "$EMAIL_CONTACT_ID = ?", arrayOf(contactId), null)

            val emailIds = arrayListOf<String>()
            while (emailCursor.moveToNext()) {

                val email = emailCursor.getString(emailCursor.getColumnIndex(DATA))
                emailIds.add(email)
            }
            emailCursor.close()
            contact.emails.addAll(emailIds)

            val columns = arrayOf(
                    ContactsContract.CommonDataKinds.Event.START_DATE,
                    ContactsContract.CommonDataKinds.Event.TYPE,
                    ContactsContract.CommonDataKinds.Event.MIMETYPE)

            val where = ContactsContract.CommonDataKinds.Event.TYPE + "=" + ContactsContract.CommonDataKinds.Event.TYPE_BIRTHDAY +
                    " and " + ContactsContract.CommonDataKinds.Event.MIMETYPE + " = '" + ContactsContract.CommonDataKinds.Event.CONTENT_ITEM_TYPE + "' and " + ContactsContract.Data.CONTACT_ID + " = " + contactId

            val selectionArgs = arrayOf<String>()
            val sortOrder = ContactsContract.Contacts.DISPLAY_NAME

            val birthdayCur = contentResolver.query(ContactsContract.Data.CONTENT_URI, columns, where, selectionArgs, sortOrder);
            val birthayList = arrayListOf<String>()
            if (birthdayCur.count > 0) {
                while (birthdayCur.moveToNext()) {
                    val birthday = birthdayCur.getString(birthdayCur.getColumnIndex(ContactsContract.CommonDataKinds.Event.START_DATE))
                    birthayList.add(birthday)
                }
            }
            birthdayCur.close()
            contact.dates.addAll(birthayList)
        }

    }

    contactsToBackup.add(contact)
    contactsCursor.close()

}

正如你所看到的，整个复杂查询的事情去上被调用超过1000次。 我怎样才能提高呢？

Answer 1:

你并不真正需要optimise thousands of SQLite queries你需要的是那些成千上万的查询迁移到一个大的查询什么。

我假设这部分：

contacts.forEach {
val lookupKey = it.lookupKey
queryContacts(lookupKey)
}

实际运行在设备上的所有联系人，如果是的话，你可以这样做：

Map<Long, Contact> contacts = new HashMap<>();

String[] projection = {Data.CONTACT_ID, Data.DISPLAY_NAME, Data.MIMETYPE, Data.DATA1, Data.DATA2, Data.DATA3};
String selection = Data.MIMETYPE + " IN ('" + Phone.CONTENT_ITEM_TYPE + "', '" + Email.CONTENT_ITEM_TYPE + "', '" + Event.CONTENT_ITEM_TYPE + "')";
Cursor cur = cr.query(Data.CONTENT_URI, projection, selection, null, null);

while (cur != null && cur.moveToNext()) {
    long id = cur.getLong(0);
    String name = cur.getString(1);
    String mime = cur.getString(2); // email / phone / event
    String data = cur.getString(3); // the actual info, e.g. [phone]
    int type = cur.getInt(4);

    Log.d(TAG, "got " + id + ", " + name + ", " + data);

    Contact contact;
    if (contacts.containsKey(id)) {
        contact = contacts.get(id);
    } else {
        contact = new Contact();
        contact.name = name;
        contacts.put(id, infos);
    }

    switch (mime) {
        case Phone.CONTENT_ITEM_TYPE: 
            contact.addPhone(data, type); // you'll need to add this method
            break;
        case Email.CONTENT_ITEM_TYPE: 
            contact.addEmail(data, type); // you'll need to add this method
            break;
        case Event.CONTENT_ITEM_TYPE: 
            contact.addBirthday(data, type); // you'll need to add this method
            break;
    }
}

文章来源: Optimise thousands of SQLite queries android