在Android应用中使用Parse的查询方法详解

在android中解析查询食谱 介绍 我们已经看到如何使用 parsequery parsequery 和 get get 从back4app检索单个 parsequery parsequery 。还有许多其他方法可以使用 parsequery parsequery 一次检索多个对象，对您希望检索的对象使用条件等等。 在本指南中，您将深入了解 parsequery parsequery 类，并查看您可以用来构建查询的所有方法。您将使用一个简单的数据库类和一些模拟数据，通过back4app上的javascript控制台执行查询。 您可以在back4app上使用javascript控制台轻松创建模拟数据，或者您可以通过遵循 https //www back4app com/docs/android/data objects/android crud tutorial 创建自己的数据。 本教程使用在android studio 4 1 1中创建的应用程序，使用 buildtoolsversion=30 0 2 buildtoolsversion=30 0 2 , compile sdk version = 30 0 2 compile sdk version = 30 0 2 和 targetsdkversion=30 targetsdkversion=30 随时可以在我们的github仓库中访问使用本教程构建的完整android项目 https //github com/templates back4app/android parse sdk kotlin https //github com/templates back4app/android parse sdk java 前提条件 要完成本教程，我们需要： https //developer android com/studio/index html 在back4app上创建的应用程序。 注意： 请遵循 https //www back4app com/docs/get started/new parse app 以了解如何在back4app上创建parse应用程序。 一个连接到back4app的android应用程序。 注意： 请遵循 https //www back4app com/docs/android/parse android sdk 以创建一个连接到back4app的android studio项目。 一台运行android 4 1（jelly bean）或更高版本的设备（或 https //developer android com/studio/run/managing avds html )。 目标 探索 parsequery parsequery 类的不同方法，并学习您可以在android上创建的查询类型。 parsequery 类 在 parse 上的任何查询操作都使用 parsequery parsequery 对象类型，这将帮助您在整个应用程序中从 back4app 中检索特定数据。要创建一个新的 parsequery parsequery ，您需要将所需的 parsequery parsequery 子类作为参数传递，该子类将包含您的查询结果。 重要的是要知道，只有在调用检索方法（如 parsequery find parsequery find 或 parsequery get parsequery get ）后， parsequery parsequery 才会解析，因此可以设置查询并在实际调用之前链接多个修饰符。 您可以在 parsequery parsequery 类的官方文档中了解更多内容， https //parseplatform org/parse sdk android/api/ 。 在 back4app 上使用 js 控制台 在您的 back4app 应用程序仪表板中，您会找到一个非常有用的 api 控制台，您可以直接在其中运行 javascript 代码。在本指南中，您将使用它来存储和查询来自 back4app 的数据对象。在您的应用程序主仪表板中，转到 core >api console >js console。 core >api console >js console。 保存您的数据对象 要在本指南中运行查询，您首先需要用一些数据填充您的应用程序。让我们创建一个名为 profile profile 的示例类，该类使用名人姓名和以下字段模拟社交媒体个人资料类： 字符串类型 日期类型 数字（整数）类型 数组（字符串数组）类型 数组（数字数组）类型 地理点类型 可空指针类型 这里是 parse object parse object 类的创建代码，所以请在您的 api 控制台中运行它 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!'); 运行此代码后，您现在应该在数据库中拥有一个 profile profile 类，并创建了六个对象。您的新类应如下所示 现在让我们来看一下每个 parsequery parsequery 方法的示例，并简要解释它们的功能。请注意，此列表中的某些方法可以将 options options 作为附加参数，但在大多数情况下，它仅与 masterkey masterkey 的使用相关，而与本指南内容无关，因此在不相关的情况下将省略此可能性。 查询检索器 这些方法负责运行查询并检索其结果，始终存在于您的查询实现中。 这是 java 方法： 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 } 这是 kotlin 方法： 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 } 查询条件 这些方法使您能够对查询应用条件约束，这可以说是查询中最重要的操作。请记住，这些操作都可以在检索结果之前进行链式调用，因此可以实现许多组合来满足您的查询需求。 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 查询排序 在大多数查询中，排序是必不可少的，可以在parse中轻松实现，甚至可以在两个或多个排序约束之间进行链式排序。 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 字段选择 这些方法影响查询结果中可以包含哪些字段值。 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 地理点查询 这些是特定于地理点查询的方法。 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 分页 这些方法与分页工具相关，适用于将检索大量结果的查询。 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 本地数据存储 这些方法使选择查询源和使用本地数据存储成为可能。 这些是 java 方法 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 }); 这些是 kotlin 方法 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 } 结论 在本指南的最后，您学习了如何在android中使用不同的查询类型。