ArrayList排序SQLite中数据所在的位置

Question

我想在android中对arraylist进行排序，其中数据是通过数据库添加的。我该怎么做？请帮帮我。

    import android.content.ContentValues;
    import android.content.Context;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.provider.ContactsContract;
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    /**
     * Created by Imran on 10/25/2015.
     */
    public class DataSource {
        private DatabaseHelper databaseHelper;
        private SQLiteDatabase database;
        private ContactModel contactModel;

        public DataSource(Context context) {
            databaseHelper = new DatabaseHelper(context);
        }
        public void open(){
            database= databaseHelper.getWritableDatabase();
        }
        public void close(){
            databaseHelper.close();
        }
        public long insertData(ContactModel contactModel){
            this.open();
            ContentValues contentValues=new ContentValues();
            contentValues.put(DatabaseHelper.COL_NAME,contactModel.getName());
            contentValues.put(DatabaseHelper.COL_COMPANY,contactModel.getCompanyName());
            contentValues.put(DatabaseHelper.COL_DESIGNATION,contactModel.getDesignation());
            contentValues.put(DatabaseHelper.COL_PHONE_NO,contactModel.getPhoneNo());
            contentValues.put(DatabaseHelper.COL_EMAIL,contactModel.getEmail());

            long inserted=database.insert(DatabaseHelper.CONTACT_TABLE,null,contentValues);
            database.close();
            this.close();
            return inserted;
        }

        public boolean updateData(String id,ContactModel contactModel){

            this.open();
            ContentValues contentValues=new ContentValues();
            contentValues.put(DatabaseHelper.COL_NAME,contactModel.getName());
            contentValues.put(DatabaseHelper.COL_COMPANY,contactModel.getCompanyName());
            contentValues.put(DatabaseHelper.COL_DESIGNATION,contactModel.getDesignation());
            contentValues.put(DatabaseHelper.COL_PHONE_NO,contactModel.getPhoneNo());
            contentValues.put(DatabaseHelper.COL_EMAIL, contactModel.getEmail());
            long update=database.update(DatabaseHelper.CONTACT_TABLE, contentValues, DatabaseHelper.COL_ID + " = " + id,
                    null);
            if (update>0){
                return true;
            }else {
                return false;
            }
        }
        public ArrayList<ContactModel> getAllContact(){
            this.open();
            ArrayList<ContactModel> contactModelArrayList=new ArrayList<>();
            ArrayList<ContactModel> sortedContactModelArrayList=new ArrayList<>();

            Cursor cursor=database.query(DatabaseHelper.CONTACT_TABLE, null, null, null, null, null, null);
            if(cursor!=null && cursor.getCount()>0){
                cursor.moveToFirst();
                for(int i=0;i<cursor.getCount();i++){
                    String id=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_ID));
                    String name=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_NAME));
                    String company=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_COMPANY));
                    String designation=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_DESIGNATION));
                    String phoneNo=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_PHONE_NO));
                    String email=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_EMAIL));

                    contactModel=new ContactModel(id,name,company,designation,phoneNo,email);
                    contactModelArrayList.add(contactModel);
                    cursor.moveToNext();
                    this.close();

                }
            }
         /*   Collections.sort(contactModelArrayList, new Comparator<>() {
                @Override
                public int compare(String s1, String s2) {
                    return s1.compareToIgnoreCase(s2);
                }
            });*/
            sortedContactModelArrayList=Collections.sort(contactModelArrayList);
            return sortedContactModelArrayList;
        }
        public boolean delete(String id){
            this.open();
            database.delete(DatabaseHelper.CONTACT_TABLE, DatabaseHelper.COL_ID + "=" + id, null);
            this.close();
            return true;
        }
        public ContactModel singleContact(String id){
            this.open();
            Cursor cursor=database.query(DatabaseHelper.CONTACT_TABLE,
                    new String[]{DatabaseHelper.COL_ID,DatabaseHelper.COL_NAME,DatabaseHelper.COL_COMPANY,DatabaseHelper.COL_DESIGNATION,
                            DatabaseHelper.COL_PHONE_NO,DatabaseHelper.COL_EMAIL},DatabaseHelper.COL_ID +" = " + id,null,null,null ,null);
            cursor.moveToFirst();
            String mId=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_ID));
            String name=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_NAME));
            String company=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_COMPANY));
            String designation=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_DESIGNATION));
            String phoneNo=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_PHONE_NO));
            String email=cursor.getString(cursor.getColumnIndex(DatabaseHelper.COL_EMAIL));
            cursor.close();
            contactModel=new ContactModel(mId,name,company,designation,phoneNo,email);;
            this.close();
            return contactModel;
        }

    }

我做过一个项目，所有的东西都在工作，但不能按字母顺序制作数据（名称）

Answer 1

当您有一个Strings列表时，您可以按照字母顺序对它们进行排序，例如

Collections.sort(list);

其中list是具有字符串的数组