Guida Completa alle Query Parse su Android per Sviluppatori

guida alla query di parse in android introduzione abbiamo già visto come un parsequery parsequery con get get può recuperare un singolo parsequery parsequery da back4app ci sono molti altri modi per recuperare dati con parsequery parsequery puoi recuperare molti oggetti contemporaneamente, utilizzare condizioni sugli oggetti che desideri recuperare e altro ancora in questa guida, approfondirai la classe parsequery parsequery e vedrai tutti i metodi che puoi utilizzare per costruire le tue query utilizzerai una semplice classe di database con alcuni dati simulati per eseguire le query utilizzando la console javascript su back4app puoi utilizzare la console javascript su back4app per creare facilmente dati simulati, oppure puoi creare i tuoi dati con la tua app android seguendo questa guida questo tutorial utilizza un'app creata in android studio 4 1 1 con buildtoolsversion=30 0 2 buildtoolsversion=30 0 2 , compile sdk version = 30 0 2 compile sdk version = 30 0 2 e targetsdkversion=30 targetsdkversion=30 in qualsiasi momento, puoi accedere al progetto android completo costruito con questo tutorial nei nostri repository github repository di esempio kotlin repository di esempio java requisiti per completare questo tutorial, abbiamo bisogno di android studio un'app creata su back4app nota segui il tutorial nuova app parse per imparare a creare un'app parse su back4app un'app android connessa a back4app nota segui il tutorial installazione parse sdk per creare un progetto android studio connesso a back4app un dispositivo (o dispositivo virtuale ) che esegue android 4 1 (jelly bean) o versioni successive obiettivo esplora la parsequery parsequery classe, i diversi metodi e impara i tipi di query che puoi creare su android la classe parsequery qualsiasi operazione di query su parse utilizza il parsequery parsequery tipo di oggetto, che ti aiuterà a recuperare dati specifici dal tuo back4app all'interno della tua app per creare un nuovo parsequery parsequery , devi passare come parametro la parsequery parsequery sottoclasse desiderata, che è quella che conterrà i risultati della tua query è fondamentale sapere che un parsequery parsequery si risolverà solo dopo aver chiamato un metodo di recupero (come parsequery find parsequery find o parsequery get parsequery get ), quindi una query può essere impostata e diversi modificatori possono essere concatenati prima di essere effettivamente chiamati puoi leggere di più sulla parsequery parsequery classe qui nella documentazione ufficiale https //parseplatform org/parse sdk android/api/ utilizzare la console js su back4app all'interno del dashboard della tua applicazione back4app, troverai una console api molto utile in cui puoi eseguire codice javascript direttamente in questa guida utilizzerai per memorizzare e interrogare oggetti dati da back4app nella dashboard principale della tua app vai a core >api console >js console core >api console >js console salva i tuoi oggetti dati per eseguire le query in questa guida dovrai prima popolare la tua app con alcuni dati creiamo una classe di esempio chiamata profile profile , che simula una classe di profilo social utilizzando nomi di persone famose e i seguenti campi tipo stringa tipo data tipo numero (intero) tipo array (array di stringhe) tipo array (array di numeri) tipo geopoint tipo puntatore nullable ecco il codice di creazione delle classi parse object codice di creazione delle classi parse object , quindi procedi e eseguilo nella tua console api 1 // add profile objects and create table 2 // adam sandler 3 let profile = new parse object('profile'); 4 profile set('name', 'adam sandler'); 5 profile set('birthday', new date('09/09/1966')); 6 profile set('friendcount', 2); 7 profile set('favoritefoods', \['lobster', 'bread']); 8 profile set('luckynumbers', \[2, 7]); 9 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 10 await profile save(); 11 12 // britney spears 13 profile = new parse object('profile'); 14 profile set('name', 'britney spears'); 15 profile set('birthday', new date('12/02/1981')); 16 profile set('friendcount', 52); 17 profile set('favoritefoods', \['cake', 'bread']); 18 profile set('luckynumbers', \[22, 7]); 19 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 20 await profile save(); 21 22 // carson kressley 23 profile = new parse object('profile'); 24 profile set('name', 'carson kressley'); 25 profile set('birthday', new date('11/11/1969')); 26 profile set('friendcount', 12); 27 profile set('favoritefoods', \['fish', 'cookies']); 28 profile set('luckynumbers', \[8, 2]); 29 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 30 await profile save(); 31 32 // dan aykroyd 33 // creates related object membership for this user only 34 let membership = new parse object('membership'); 35 membership set('name', 'premium'); 36 membership set('expirationdate', new date('10/10/2030')) 37 await membership save(); 38 profile = new parse object('profile'); 39 profile set('name', 'dan aykroyd'); 40 profile set('birthday', new date('07/01/1952')); 41 profile set('friendcount', 66); 42 profile set('favoritefoods', \['jam', 'peanut butter']); 43 profile set('luckynumbers', \[22, 77]); 44 profile set('lastloginlocation', new parse geopoint(37 38412167489413, 122 01268034622319)); 45 profile set('premiummembership', membership); 46 await profile save(); 47 48 // eddie murphy 49 profile = new parse object('profile'); 50 profile set('name', 'eddie murphy'); 51 profile set('birthday', new date('04/03/1961')); 52 profile set('friendcount', 49); 53 profile set('favoritefoods', \['lettuce', 'pepper']); 54 profile set('luckynumbers', \[6, 5]); 55 profile set('lastloginlocation', new parse geopoint( 27 104919974838154, 52 61428045237739)); 56 await profile save(); 57 58 // fergie 59 profile = new parse object('profile'); 60 profile set('name', 'fergie'); 61 profile set('birthday', new date('03/27/1975')); 62 profile set('friendcount', 55); 63 profile set('favoritefoods', \['lobster', 'shrimp']); 64 profile set('luckynumbers', \[13, 7]); 65 profile set('lastloginlocation', new parse geopoint( 27 104919974838154, 52 61428045237739)); 66 await profile save(); 67 68 console log('success!'); dopo aver eseguito questo codice, ora dovresti avere una profilo profilo classe nel tuo database con sei oggetti creati la tua nuova classe dovrebbe apparire così diamo ora un'occhiata agli esempi di ogni parsequery parsequery metodo, insieme a brevi spiegazioni su cosa fanno si prega di notare che alcuni metodi in questo elenco possono prendere opzioni opzioni come argomento aggiuntivo, ma nella maggior parte dei casi, è solo relativo all'uso del masterkey masterkey e non rilevante per il contenuto di questa guida, quindi questa possibilità sarà omessa ogni volta che non è rilevante recuperatori di query questi metodi sono responsabili dell'esecuzione della query e del recupero dei suoi risultati, essendo sempre presenti nell'implementazione della tua query questi sono i java metodi cancel //cancels the current network request 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query findinbackground(); 3 query cancel(); count //retrieves the count of parseobject results that meet the query criteria 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 try { 3 int querycount = query count(); 4 log d(tag, "count " + querycount); 5 } catch (com parse parseexception parseexception) { 6 parseexception printstacktrace(); 7 } find //this is the basic method for retrieving your query results, always returning an array of parseobject instances, being empty when none are found 1 //this find function works synchronously 2 parsequery\<parseobject> query = new parsequery<>("profile"); 3 try { 4 list\<parseobject> list = query find(); 5 log d(tag, "list " + list); 6 } catch (com parse parseexception e) { 7 e printstacktrace(); 8 } findinbackground //this is the basic method for retrieving your query results, always returning an array of parseobject instances, being empty when none are found 1 //this find function works asynchronously 2 parsequery\<parseobject> query = new parsequery<>("profile"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parseerror ", e); 8 } 9 }); first //retrieves the first parseobject instance that meets the query criteria 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 try { 3 parseobject firstitem = query getfirst(); 4 log d(tag, "first item " + firstitem); 5 } catch (parseexception e) { 6 e printstacktrace(); 7 } get //this quick method is used to retrieve a single parseobject instance when you know its objectid 1 //we can call a parse object with an object id with the get() function 2 parsequery\<parseobject> query = new parsequery<>("profile"); 3 try { 4 parseobject object = query get("c6endlnfdq"); 5 log d(tag, "object " + object); 6 } catch (parseexception e) { 7 e printstacktrace(); 8 } questi sono i kotlin metodi cancel //cancels the current network request 1 val query = parsequery\<parseobject>("profile") 2 query findinbackground() 3 query cancel() count //retrieves the count of parseobject results that meet the query criteria 1 val query = parsequery\<parseobject>("profile") 2 try { 3 val querycount = query count() 4 log d(companion tag, "count $querycount") 5 } catch (parseexception parseexception) { 6 parseexception printstacktrace() 7 } find //this is the basic method for retrieving your query results, always returning an array of parseobject instances, being empty when none are found 1 //this find function works synchronously 2 val query = parsequery\<parseobject>("profile") 3 try { 4 val list = query find() 5 log d(companion tag, "list $list") 6 } catch (e parseexception) { 7 e printstacktrace() 8 } findinbackground //this is the basic method for retrieving your query results, always returning an array of parseobject instances, being empty when none are found 1 //this find function works asynchronously 2 val query = parsequery\<parseobject>("profile") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parseerror ", e) 8 } 9 } first //retrieves the first parseobject instance that meets the query criteria 1 val query = parsequery\<parseobject>("profile") 2 try { 3 val firstitem = query first 4 log d(companion tag, "first item $firstitem") 5 } catch (e parseexception) { 6 e printstacktrace() 7 } get //this quick method is used to retrieve a single parseobject instance when you know its objectid 1 //we can call a parse object with an object id with the get() function 2 val query = parsequery\<parseobject>("profile") 3 try { 4 val `object` = query\["c6endlnfdq"] 5 log d(companion tag, "object $`object`") 6 } catch (e parseexception) { 7 e printstacktrace() 8 } condizioni di query questi metodi ti danno la possibilità di applicare vincoli condizionali alla tua query, che sono senza dubbio le operazioni più importanti nella query ricorda che queste operazioni possono essere concatenate prima che i risultati vengano recuperati, quindi molte combinazioni possono essere raggiunte per soddisfare le tue esigenze di query questi sono java metodi containedin //filters objects in which a key value is contained in the provided array of values 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherecontainedin("luckynumbers", list of(2, 7)); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); contains //filters objects in which a string key value contains the provided text value be aware that this condition is case sensitive 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherecontains("name", "da"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); cointansall //filters objects in which an array type key value must contain every value provided 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherecontainsall("luckynumbers", list of(2, 7)); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); containsallstartingwith //filters objects in which an array type key value must contain every string value provided 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherecontainsallstartswith("favoritefoods", list of("shrimp", "lobster")); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); doesnotexist //filters objects in which a key value is not set 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wheredoesnotexist("premiummembership"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); questi sono kotlin metodi containedin //filters objects in which a key value is contained in the provided array of values 1 val query = parsequery\<parseobject>("profile") 2 query wherecontainedin("luckynumbers", java util list of(2, 7)) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } contains //filters objects in which a string key value contains the provided text value be aware that this condition is case sensitive 1 val query = parsequery\<parseobject>("profile") 2 query wherecontains("name", "da") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } cointansall //filters objects in which an array type key value must contain every value provided 1 val query = parsequery\<parseobject>("profile") 2 query wherecontainsall("luckynumbers", java util list of(2, 7)) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } containsallstartingwith //filters objects in which an array type key value must contain every string value provided 1 val query = parsequery\<parseobject>("profile") 2 query wherecontainsallstartswith("favoritefoods", java util list of("shrimp", "lobster")) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } doesnotexist //filters objects in which a key value is not set 1 val query = parsequery\<parseobject>("profile") 2 query wheredoesnotexist("premiummembership") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } questi sono java metodi canceldoesnotmatchkeyinquery //requires that a key’s value does not match a value in an object returned by a different parsequery useful for multi object querying 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 parsequery\<parseobject> innerquery = new parsequery<>("profile"); 3 innerquery wherelessthan("friendcount", 50); 4 query wheredoesnotmatchkeyinquery("friendcount", "friendcount", innerquery); 5 query wheregreaterthan("friendcount", 10); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 }); doesnotmatchquery //requires that an object contained in the given key does not match another query useful for multi object querying 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 parsequery\<parseobject> innerquery = new parsequery<>("membership"); 3 innerquery wheregreaterthan("expirationdate", new date()); 4 query whereexists("premiummembership"); 5 query wheredoesnotmatchquery("premiummembership", innerquery); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 }); endswith //filters objects in which a string key’s value ends with the provided text value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query whereendswith("name", "ie"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); equalto //filters objects in which a specific key’s value is equal to the provided value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query whereequalto("friendcount", 2); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); exists //filters objects in which a key value is set 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query whereexists("premiummembership"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); fulltext //filters objects in which a string key’s value wrap matches the provided text value in it it can have many customizable options to improve its results, like language specification and score order 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherefulltext("name", "spears"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); greaterthan //filters objects in which a specific key’s value is greater than the provided value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 calendar calendar = calendar getinstance(); 3 calendar set(1980, 8, 19, 59, 59, 59); 4 date date = calendar gettime(); 5 query wheregreaterthan("birthday", date); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 }); greaterthanorequalto //filters objects in which a specific key’s value is greater than or equal to the provided value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wheregreaterthanorequalto("friendcount", 49); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); questi sono kotlin metodi canceldoesnotmatchkeyinquery //requires that a key’s value does not match a value in an object returned by a different parsequery useful for multi object querying 1 val query = parsequery\<parseobject>("profile") 2 val innerquery = parsequery\<parseobject>("profile") 3 innerquery wherelessthan("friendcount", 50) 4 query wheredoesnotmatchkeyinquery("friendcount", "friendcount", innerquery) 5 query wheregreaterthan("friendcount", 10) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } doesnotmatchquery //requires that an object contained in the given key does not match another query useful for multi object querying 1 val query = parsequery\<parseobject>("profile") 2 val innerquery = parsequery\<parseobject>("membership") 3 innerquery wheregreaterthan("expirationdate", date()) 4 query whereexists("premiummembership") 5 query wheredoesnotmatchquery("premiummembership", innerquery) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } endswith //filters objects in which a string key’s value ends with the provided text value 1 val query = parsequery\<parseobject>("profile") 2 query whereendswith("name", "ie") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } equalto //filters objects in which a specific key’s value is equal to the provided value 1 val query = parsequery\<parseobject>("profile") 2 query whereequalto("friendcount", 2) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } exists //filters objects in which a key value is set 1 val query = parsequery\<parseobject>("profile") 2 query whereexists("premiummembership") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } fulltext //filters objects in which a string key’s value wrap matches the provided text value in it it can have many customizable options to improve its results, like language specification and score order 1 val query = parsequery\<parseobject>("profile") 2 query wherefulltext("name", "spears") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } greaterthan //filters objects in which a specific key’s value is greater than the provided value 1 val query = parsequery\<parseobject>("profile") 2 val calendar = calendar getinstance() 3 calendar\[1980, 8, 19, 59, 59] = 59 4 val date = calendar time 5 query wheregreaterthan("birthday", date) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } greaterthanorequalto //filters objects in which a specific key’s value is greater than or equal to the provided value 1 val query = parsequery\<parseobject>("profile") 2 query wheregreaterthanorequalto("friendcount", 49) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } questi sono java metodi lessthan //filters objects in which a specific key’s value is lesser than the provided value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 calendar calendar = calendar getinstance(); 3 calendar set(1980, 8, 19, 59, 59, 59); 4 date date = calendar gettime(); 5 query wherelessthan("birthday", date); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 }); lessthanorequalto //filters objects in which a specific key’s value is lesser than or equal to the provided value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherelessthanorequalto("friendcount", 49); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); matches //filters objects in which a string type key value must match the provided regular expression and its modifiers 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherematches("name", "da", "i"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); matcheskeyinquery //requires that a key’s value matches a value in an object returned by a different parsequery useful for multi object querying 1 parsequery\<parseobject> query = new parsequery<>("profile"); 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 parsequery\<parseobject> innerquery = new parsequery<>("profile"); 3 innerquery wherelessthan("friendcount", 50); 4 query wherematcheskeyinquery("friendcount", "friendcount", innerquery); 5 query wheregreaterthan("friendcount", 10); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 }); matchesquery //requires that an object contained in the given key matches another query useful for multi object querying 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 parsequery\<parseobject> innerquery = new parsequery<>("membership"); 3 innerquery wheregreaterthan("expirationdate", new date()); 4 query whereexists("premiummembership"); 5 query wherematchesquery("premiummembership", innerquery); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 }); notequalto //filters objects in which a specific key’s value is not equal to the provided value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherenotequalto("friendcount", 2); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); startswith //filters objects in which a string key’s value starts with the provided text value 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherestartswith("name", "brit"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); questi sono kotlin metodi lessthan //filters objects in which a specific key’s value is lesser than the provided value 1 val query = parsequery\<parseobject>("profile") 2 val calendar = calendar getinstance() 3 calendar\[1980, 8, 19, 59, 59] = 59 4 val date = calendar time 5 query wherelessthan("birthday", date) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } lessthanorequalto //filters objects in which a specific key’s value is lesser than or equal to the provided value 1 val query = parsequery\<parseobject>("profile") 2 query wherelessthanorequalto("friendcount", 49) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } matches //filters objects in which a string type key value must match the provided regular expression and its modifiers 1 val query = parsequery\<parseobject>("profile") 2 query wherematches("name", "da", "i") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } matcheskeyinquery //requires that a key’s value matches a value in an object returned by a different parsequery useful for multi object querying 1 parsequery\<parseobject> query = new parsequery<>("profile"); 1 val query = parsequery\<parseobject>("profile") 2 val innerquery = parsequery\<parseobject>("profile") 3 innerquery wherelessthan("friendcount", 50) 4 query wherematcheskeyinquery("friendcount", "friendcount", innerquery) 5 query wheregreaterthan("friendcount", 10) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } matchesquery //requires that an object contained in the given key matches another query useful for multi object querying 1 val query = parsequery\<parseobject>("profile") 2 val innerquery = parsequery\<parseobject>("membership") 3 innerquery wheregreaterthan("expirationdate", date()) 4 query whereexists("premiummembership") 5 query wherematchesquery("premiummembership", innerquery) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } notequalto //filters objects in which a specific key’s value is not equal to the provided value 1 val query = parsequery\<parseobject>("profile") 2 query wherenotequalto("friendcount", 2) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } startswith //filters objects in which a string key’s value starts with the provided text value 1 val query = parsequery\<parseobject>("profile") 2 query wherestartswith("name", "brit") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } ordinamento delle query essenziale nella maggior parte delle query, l'ordinamento può essere facilmente ottenuto in parse e persino concatenato tra due o più vincoli di ordinamento questi sono java metodi addascending //sort the results in ascending order, overwrites previous orderings multiple keys can be used to solve ordering ties 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query addascendingorder("friendcount"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); adddescending //sort the results in descending order, overwrites previous orderings multiple keys can be used to solve ordering ties 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query adddescendingorder("friendcount"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); ascending //sort the results in ascending order, this can be chained without overwriting previous orderings multiple keys can be used to solve ordering ties 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query orderbyascending("friendcount"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); descending //sort the results in descending order, this can be chained without overwriting previous orderings multiple keys can be used to solve ordering ties 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query orderbydescending("friendcount"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); questi sono kotlin metodi addascending //sort the results in ascending order, overwrites previous orderings multiple keys can be used to solve ordering ties 1 val query = parsequery\<parseobject>("profile") 2 query addascendingorder("friendcount") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } adddescending //sort the results in descending order, overwrites previous orderings multiple keys can be used to solve ordering ties 1 val query = parsequery\<parseobject>("profile") 2 query adddescendingorder("friendcount") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } ascending //sort the results in ascending order, this can be chained without overwriting previous orderings multiple keys can be used to solve ordering ties 1 val query = parsequery\<parseobject>("profile") 2 query orderbyascending("friendcount") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } descending //sort the results in descending order, this can be chained without overwriting previous orderings multiple keys can be used to solve ordering ties 1 val query = parsequery\<parseobject>("profile") 2 query orderbydescending("friendcount") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } selezione dei campi questi metodi influenzano quali valori di campo possono essere nei risultati della tua query questi sono java metodi include //return all fields in the returned objects except the ones specified 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query whereexists("premiummembership"); 3 query include("premiummembership"); 4 query findinbackground((objects, e) > { 5 if (e == null) { 6 log d(tag, "objects " + objects); 7 log d(tag, "object premium membership " + objects get(0) get("premiummembership")); 8 } else { 9 log e(tag, "parse error ", e); 10 } 11 12 }); select //return only the specified fields in the returned objects 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query selectkeys(list of("name")); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 log d(tag, "object name " + objects get(0) get("name")); 7 } else { 8 log e(tag, "parse error ", e); 9 } 10 11 }); questi sono kotlin metodi include //return all fields in the returned objects except the ones specified 1 val query = parsequery\<parseobject>("profile") 2 query whereexists("premiummembership") 3 query include("premiummembership") 4 query findinbackground { objects list\<parseobject>, e parseexception? > 5 if (e == null) { 6 log d(companion tag, "objects $objects") 7 log d( 8 companion tag, 9 "object premium membership " + objects\[0]\["premiummembership"] 10 ) 11 } else { 12 log e(companion tag, "parse error ", e) 13 } 14 } select //return only the specified fields in the returned objects 1 val query = parsequery\<parseobject>("profile") 2 query selectkeys(java util list of("name")) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 log d(companion tag, "object name " + objects\[0]\["name"]) 7 } else { 8 log e(companion tag, "parse error ", e) 9 } 10 } interrogazione geopoint questi sono metodi specifici per l'interrogazione di geopoint questi sono java metodi near //order objects by how near the key value is from the given geopoint 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherenear("lastloginlocation", new parsegeopoint(37 38412167489413, 122 01268034622319)); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); polygoncontains //find objects whose key value contains the specified geopoint 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherepolygoncontains("lastloginlocation", new parsegeopoint(37 38412167489413, 122 01268034622319)); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); withingeobox //find objects whose key value is contained within the specified bounding box, composed by two geopoint values that set the lower left and upper right corner values 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherewithingeobox("lastloginlocation", new parsegeopoint(37 48412167489413, 122 11268034622319), new parsegeopoint(37 28412167489413, 121 91268034622319)); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); withinkilometers //find objects whose key value is near the given geopoint and within the maxdistance value the sorted boolean value determines if the results should be sorted by distance ascending 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherewithinkilometers("lastloginlocation", new parsegeopoint(37 38412167489413, 122 01268034622319), 100); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); withinmiles //find objects whose key value is near the given geopoint and within the maxdistance value the sorted boolean value determines if the results should be sorted by distance ascending 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherewithinmiles("lastloginlocation", new parsegeopoint(37 38412167489413, 122 01268034622319), 100); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); withinpolygon //find objects whose key value is contained within the specified polygon, composed of an array of geopoints (at least three) if the polygon path is open, it will be closed automatically by parse connecting the last and first points 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherewithinpolygon("lastloginlocation", list of(new parsegeopoint(37 48412167489413, 122 11268034622319), 3 new parsegeopoint(37 48412167489413, 121 91268034622319), 4 new parsegeopoint(37 28412167489413, 121 91268034622319), 5 new parsegeopoint(37 28412167489413, 122 01268034622319))); 6 query findinbackground((objects, e) > { 7 if (e == null) { 8 log d(tag, "objects " + objects); 9 } else { 10 log e(tag, "parse error ", e); 11 } 12 13 }); withinradians //find objects whose key value is near the given geopoint and within the maxdistance value the sorted boolean value determines if the results should be sorted by distance ascending 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query wherewithinradians("lastloginlocation", new parsegeopoint(37 38412167489413, 122 01268034622319), 100); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); questi sono kotlin metodi near //order objects by how near the key value is from the given geopoint 1 val query = parsequery\<parseobject>("profile") 2 query wherenear("lastloginlocation", parsegeopoint(37 38412167489413, 122 01268034622319)) 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } polygoncontains //find objects whose key value contains the specified geopoint 1 val query = parsequery\<parseobject>("profile") 2 query wherepolygoncontains( 3 "lastloginlocation", 4 parsegeopoint(37 38412167489413, 122 01268034622319) 5 ) 6 query findinbackground { objects list\<parseobject>, e parseexception? > 7 if (e == null) { 8 log d(companion tag, "objects $objects") 9 } else { 10 log e(companion tag, "parse error ", e) 11 } 12 } withingeobox //find objects whose key value is contained within the specified bounding box, composed by two geopoint values that set the lower left and upper right corner values 1 val query = parsequery\<parseobject>("profile") 2 query wherewithingeobox( 3 "lastloginlocation", 4 parsegeopoint(37 48412167489413, 122 11268034622319), 5 parsegeopoint(37 28412167489413, 121 91268034622319) 6 ) 7 query findinbackground { objects list\<parseobject>, e parseexception? > 8 if (e == null) { 9 log d(companion tag, "objects $objects") 10 } else { 11 log e(companion tag, "parse error ", e) 12 } 13 } withinkilometers //find objects whose key value is near the given geopoint and within the maxdistance value the sorted boolean value determines if the results should be sorted by distance ascending 1 val query = parsequery\<parseobject>("profile") 2 query wherewithinkilometers( 3 "lastloginlocation", 4 parsegeopoint(37 38412167489413, 122 01268034622319), 5 100 0 6 ) 7 query findinbackground { objects list\<parseobject>, e parseexception? > 8 if (e == null) { 9 log d(companion tag, "objects $objects") 10 } else { 11 log e(companion tag, "parse error ", e) 12 } 13 } withinmiles //find objects whose key value is near the given geopoint and within the maxdistance value the sorted boolean value determines if the results should be sorted by distance ascending 1 val query = parsequery\<parseobject>("profile") 2 query wherewithinmiles( 3 "lastloginlocation", 4 parsegeopoint(37 38412167489413, 122 01268034622319), 5 100 0 6 ) 7 query findinbackground { objects list\<parseobject>, e parseexception? > 8 if (e == null) { 9 log d(companion tag, "objects $objects") 10 } else { 11 log e(companion tag, "parse error ", e) 12 } 13 } withinpolygon //find objects whose key value is contained within the specified polygon, composed of an array of geopoints (at least three) if the polygon path is open, it will be closed automatically by parse connecting the last and first points 1 val query = parsequery\<parseobject>("profile") 2 query wherewithinpolygon( 3 "lastloginlocation", java util list of( 4 parsegeopoint(37 48412167489413, 122 11268034622319), 5 parsegeopoint(37 48412167489413, 121 91268034622319), 6 parsegeopoint(37 28412167489413, 121 91268034622319), 7 parsegeopoint(37 28412167489413, 122 01268034622319) 8 ) 9 ) 10 query findinbackground { objects list\<parseobject>, e parseexception? > 11 if (e == null) { 12 log d(companion tag, "objects $objects") 13 } else { 14 log e(companion tag, "parse error ", e) 15 } 16 } withinradians //find objects whose key value is near the given geopoint and within the maxdistance value the sorted boolean value determines if the results should be sorted by distance ascending 1 val query = parsequery\<parseobject>("profile") 2 query wherewithinradians( 3 "lastloginlocation", 4 parsegeopoint(37 38412167489413, 122 01268034622319), 5 100 0 6 ) 7 query findinbackground { objects list\<parseobject>, e parseexception? > 8 if (e == null) { 9 log d(companion tag, "objects $objects") 10 } else { 11 log e(companion tag, "parse error ", e) 12 } 13 } paginazione questi metodi sono correlati agli strumenti di paginazione, utili per le query che recupereranno un gran numero di risultati questi sono java metodi limit //sets the maximum value of returned results, the default value is 100 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query setlimit(2); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); skip //skips the first n results in the query, essential for pagination 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query setskip(2); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); questi sono kotlin metodi limit //sets the maximum value of returned results, the default value is 100 1 val query = parsequery\<parseobject>("profile") 2 query limit = 2 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } skip //skips the first n results in the query, essential for pagination 1 val query = parsequery\<parseobject>("profile") 2 query skip = 2 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } datastore locale questi metodi consentono di selezionare la fonte delle query e di utilizzare un datastore locale questi sono java metodi fromlocaldatastore //changes the source of this query to all pinned objects 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 //if you want use localdatastore you should enable local data store in the app java or app kt file 3 query fromlocaldatastore(); 4 query findinbackground((objects, e) > { 5 if (e == null) { 6 log d(tag, "objects " + objects); 7 } else { 8 log e(tag, "parse error ", e); 9 } 10 11 }); fromnetwork //changes the source of this query to your online server 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query fromnetwork(); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); frompin //changes the source of this query to the default group of pinned objects 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query frompin(); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 10 }); frompinwithname //changes the source of this query to a specific group of pinned objects 1 parsequery\<parseobject> query = new parsequery<>("profile"); 2 query frompin("pinnedobjects"); 3 query findinbackground((objects, e) > { 4 if (e == null) { 5 log d(tag, "objects " + objects); 6 } else { 7 log e(tag, "parse error ", e); 8 } 9 }); questi sono metodi kotlin fromlocaldatastore //changes the source of this query to all pinned objects 1 val query = parsequery\<parseobject>("profile") 2 //if you want use localdatastore you should enable local data store in the app java or app kt file 3 query fromlocaldatastore() 4 query findinbackground { objects list\<parseobject>, e parseexception? > 5 if (e == null) { 6 log d(companion tag, "objects $objects") 7 } else { 8 log e(companion tag, "parse error ", e) 9 } 10 } fromnetwork //changes the source of this query to your online server 1 val query = parsequery\<parseobject>("profile") 2 query fromnetwork() 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } frompin //changes the source of this query to the default group of pinned objects 1 val query = parsequery\<parseobject>("profile") 2 query frompin() 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } frompinwithname //changes the source of this query to a specific group of pinned objects 1 val query = parsequery\<parseobject>("profile") 2 query frompin("pinnedobjects") 3 query findinbackground { objects list\<parseobject>, e parseexception? > 4 if (e == null) { 5 log d(companion tag, "objects $objects") 6 } else { 7 log e(companion tag, "parse error ", e) 8 } 9 } conclusione alla fine di questa guida, hai imparato come utilizzare diversi tipi di query in android