Data Types

this guide introduces parse data types in flutter, using examples from the main dart file parse data storage revolves around parseobject, which contains key value pairs of json compatible data, making it schemaless this means you can store any data without defining a schema in advance you can set whatever key value pairs you want, and our backend will store them for example, let’s say you’re tracking high scores for a game a single parse object could contain we suggest you nameyourclasseslikethis and nameyourkeyslikethis to enhance code readability and maintainability understanding our app to better understand back4app, let's explore code examples of parse operations in a flutter application with the major supported data types this guide won’t explain any flutter app code as the primary focus is using parse with flutter prerequisites to complete this tutorial, you will need android studio https //developer android com/studio or vs code installed (with plugins dart and flutter) an app created on back4app note follow the new parse app tutorial to learn how to create a parse app on back4app a flutter app connected to back4app note follow the install parse sdk on the flutter project to create a flutter project connected to back4app a device (or virtual device) running android or ios 1 working with parse objects each parseobject has a class name (e g , gamepoint) used to distinguish different data types here’s how you can create and save a new parse object with data types string , int , & boolean final gamepoint = parseobject('gamepoint') set('score', 1337) set('playername', 'sean plott') set('cheatmode', false); await gamepoint save(); to query the new parse object and retrieve the data types final querybuilder\<parseobject> querygamepoints = querybuilder\<parseobject>(parseobject('gamepoint')); final parseresponse response = await querygamepoints query(); if (response success && response results != null) { for (var gamepoint in response results!) { final score = gamepoint get\<int>('score'); final playername = gamepoint get\<string>('playername'); final cheatmode = gamepoint get\<bool>('cheatmode'); } 2 counters you can increment or decrement an integer field in a parseobject using the set() method however, this isn't effective and can lead to problems if multiple clients are trying to update the same counter parse provides two methods that automatically increment and decrement any number field to store counter type data setincrement() setdecrement() an update to increment a counter int value will be written as final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' setincrement('intfield', 1); await gamepoint save(); to decrement final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' setdecrement('intfield', 1); await gamepoint save(); using setincrement() and setdecrement() with the save() call allows you to update a value as part of a larger save operation where you may be modifying multiple fields this is better to avoid extra network requests 3 lists parse provides methods to work with list data, including setadd , setaddunique , setremove , and their respective all versions list \["a","b","c"] 3 1 setadd final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' setadd('liststringfield', 'd'); await gamepoint save(); result \["a","b","c","d"] 3 2 setaddall final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' setaddall('liststringfield', \['e','f']); await gamepoint save(); result \["a","b","c","d","e","f"] setaddall does not add duplicate elements if the list already contains them 3 3 setaddunique final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' setaddunique('liststringfield', \['a', 'e', 'g']); await gamepoint save(); result \["a","b","c","d","e","f","g"] 3 4 setremove final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' setremove('liststringfield', 'd'); await gamepoint save(); result \["a","b","c","e","f","g"] 4 remove field from parseobject you can delete a single field from an object by using the unset operation final gamepoint = parseobject('gamepoint') objectid = 'yourobjectid' unset("liststringfield"); 5 files parsefile lets you store and retrieve application files in the cloud below is a basic example of uploading a local image file to back4app // create parsefile object final parsefile = parsefile(file(image path)); final response = await parsefile save(); if (response success) { print('file uploaded successfully ${parsefile url}'); // save this file in an object final gamepoint = parseobject('gamepoint') set('title', 'post with an image') set('imagefile', parsefile); // saving the file as a field final postresponse = await gamepoint save(); } this code snippet shows how to retrieve the image file final query = querybuilder\<parseobject>(parseobject('gamepoint')); final response = await query query(); if (response success && response results != null) { for (var gamepoint in response results!) { parsefilebase? varfile = gamepoint get\<parsefilebase>('file'); if (varfile != null) { final fileurl = varfile url; print('game title image url $fileurl'); } else { print('no file found for this object '); } } } starting from parse server 5 2 3 they are breaking changes that could cause errors during an attempt to upload files follow this guide https //www back4app com/docs/platform/parse server version#o cil to fix any upload issues you may experience a later guide will further discuss and show templates on how to save and display files with parse https //www back4app com/docs/flutter/parse sdk/flutter save file 6 geopoint parse allows you to associate real world latitude and longitude coordinates with an object with its geopoint data type adding a parsegeopoint to a parseobject will enable queries to consider the proximity of an object to a reference point example // request permission here and get the current location the `position` object // create geopoint object final geopoint = parsegeopoint(latitude position latitude, longitude position longitude); // create an object with the geopoint final gamepoint = parseobject('gamepoint') set('name', 'current location') set('location', geopoint); // save the geopoint in a field final response = await gamepoint save(); you can find a standalone example of saving geopoint location in this main dart https //github com/templates back4app/flutter datatypes/blob/18c4c372eb49c1cd950eeaac355564134a5e70c4/lib/src/main dart file full app example this example demonstrates how to create, delete, and update a gamepoint parse object handle various data types, including strings, doubles, booleans, files, geopoint, lists, and dates on ios, you will need to grant your simulator the necessary access permissions ios provides a developer guide on protected resources the example applications in this guide will require the location https //developer apple com/documentation/bundleresources/information property list/nslocationwheninuseusagedescription and photos https //developer apple com/documentation/bundleresources/information property list/nsphotolibraryaddusagedescription permission keys found in that guide to work add the keys to the info plist file, located at /ios/runner/info plist you can skip the above step if you are running your flutter app on the web import 'dart\ async'; import 'package\ flutter/material dart'; import 'package\ parse server sdk flutter/parse server sdk flutter dart'; import 'package\ image picker/image picker dart'; import 'package\ flutter/foundation dart'; import 'dart\ io'; void main() async { widgetsflutterbinding ensureinitialized(); const keyparseapplicationid = 'your application id'; const keyparseclientkey = 'your client key'; const keyparseserverurl = 'https //parseapi back4app com'; await parse() initialize( keyparseapplicationid, keyparseserverurl, clientkey keyparseclientkey, autosendsessionid true, debug true, ); runapp(const myapp()); } class myapp extends statelesswidget { const myapp({super key}); @override widget build(buildcontext context) { return materialapp( title 'datatypes', theme themedata( primaryswatch colors blue, ), home const myhomepage(), ); } } class myhomepage extends statefulwidget { const myhomepage({super key}); @override myhomepagestate createstate() => myhomepagestate(); } class myhomepagestate extends state\<myhomepage> { final texteditingcontroller stringcontroller = texteditingcontroller(); final texteditingcontroller doublecontroller = texteditingcontroller(); final texteditingcontroller liststringcontroller = texteditingcontroller(); final texteditingcontroller listintcontroller = texteditingcontroller(); final texteditingcontroller pointercontroller = texteditingcontroller(); final texteditingcontroller objectidcontroller = texteditingcontroller(); final texteditingcontroller uniquevaluecontroller = texteditingcontroller(); final texteditingcontroller removevaluecontroller = texteditingcontroller(); bool boolvalue = false; datetime selecteddate = datetime now(); final string responsemessage = ''; xfile? pickedfile; bool isloading = false; @override widget build(buildcontext context) { return scaffold( appbar appbar( title const text('datatypes'), ), body padding( padding const edgeinsets all(16 0), child singlechildscrollview( child column( crossaxisalignment crossaxisalignment start, children \<widget>\[ buildtextfield('string field', stringcontroller), const sizedbox(height 20), buildtextfield('double field', doublecontroller, isnumeric true), const sizedbox(height 20), buildswitch('bool field', boolvalue, (value) { setstate(() { boolvalue = value; }); }), const sizedbox(height 20), textbutton( onpressed () => selectdate(context), child text( 'select date ${ selecteddate tolocal()}' split(' ')\[0]), ), const sizedbox(height 20), buildtextfield( 'list string field (comma separated)', liststringcontroller), const sizedbox(height 20), buildtextfield( 'list int field (comma separated)', listintcontroller), const sizedbox(height 20), buildtextfield('pointer field (object id)', pointercontroller), const sizedbox(height 20), buildimagepicker(), const sizedbox(height 20), elevatedbutton( onpressed savedata, child const text('save'), ), const sizedbox(height 20), elevatedbutton( onpressed () async { await deletedata( objectidcontroller text); // await dummyfunction(); }, child const text('delete'), ), const sizedbox(height 20), buildtextfield( 'object id to delete or update', objectidcontroller), elevatedbutton( onpressed () async { await updatedata( objectidcontroller text); }, child const text('update'), ), const sizedbox(height 20), buildincrementdecrementbuttons(), const sizedbox(height 20), buildlistoperations(), const sizedbox(height 20), text( responsemessage), ], ), ), ), ); } widget buildtextfield(string label, texteditingcontroller controller, {bool isnumeric = false}) { return textfield( controller controller, keyboardtype isnumeric ? textinputtype number textinputtype text, decoration inputdecoration( border const outlineinputborder(), labeltext label, ), ); } widget buildswitch(string label, bool value, function(bool) onchanged) { return switchlisttile( title text(label), value value, onchanged onchanged, ); } widget buildimagepicker() { return gesturedetector( child pickedfile != null ? container( width 250, height 250, decoration boxdecoration(border border all(color colors blue)), child kisweb ? image network(pickedfile! path) image file(file(pickedfile! path)), ) container( width 250, height 250, decoration boxdecoration(border border all(color colors blue)), child const center( child text('click here to pick image from gamepoint')), ), ontap () async { final picker = imagepicker(); xfile? image = (await picker pickimage(source imagesource gallery)); if (image != null) { setstate(() { pickedfile = image; }); } }, ); } widget buildincrementdecrementbuttons() { return row( mainaxisalignment mainaxisalignment spacebetween, children \[ expanded( child elevatedbutton( onpressed () async { await incrementfield( objectidcontroller text); }, child const text('+ double'), ), ), const sizedbox(width 10), // adding some space between buttons expanded( child elevatedbutton( onpressed () async { await decrementfield( objectidcontroller text); }, child const text(' double'), ), ), ], ); } widget buildlistoperations() { return column( children \[ buildtextfield('unique value to add', uniquevaluecontroller), elevatedbutton( onpressed () async { await adduniquetolist( objectidcontroller text, uniquevaluecontroller text); }, child const text('add unique'), ), const sizedbox(height 20), buildtextfield('value to remove', removevaluecontroller), elevatedbutton( onpressed () async { await removefromlist( objectidcontroller text, removevaluecontroller text); }, child const text('remove'), ), ], ); } future\<void> savedata() async { //parse values string stringvalue = stringcontroller text; list\<string> liststringvalue = liststringcontroller text isnotempty ? liststringcontroller text split(',') // split by comma map((e) => e trim()) // remove any surrounding whitespace from each element tolist() \[]; list\<int> listtintvalue = listintcontroller text isnotempty ? listintcontroller text split(',') // split by comma map( (e) => int parse(e trim())) // convert each string to an integer tolist() \[]; double? doublevalue; if ( doublecontroller text isnotempty) { doublevalue = double parse( doublecontroller text); } bool boolvalue = boolvalue; datetime selecteddate = selecteddate; final gamepoint = parseobject('gamepoint') set('bool', boolvalue) set('date', selecteddate); if (stringvalue isnotempty) gamepoint set('string', stringvalue); if (doublevalue != null) gamepoint set('double', doublevalue); if (liststringvalue isnotempty) { gamepoint setaddall('liststring', liststringvalue); } if (listtintvalue isnotempty) gamepoint setaddall('listint', listtintvalue); if ( pointercontroller text isnotempty) { gamepoint set('pointer', parsepointer( pointercontroller text)); } if (pickedfile != null) { setstate(() { isloading = true; }); parsefilebase? parsefile; if (kisweb) { parsefile = parsewebfile(await pickedfile! readasbytes(), name 'file jpg'); } else { parsefile = parsefile(file(pickedfile! path)); } await parsefile save(); gamepoint set('file', parsefile); } var apiresponse = await gamepoint save(); if (apiresponse success && apiresponse results != null) { setstate(() { isloading = false; pickedfile = null; }); scaffoldmessenger of(context) removecurrentsnackbar() showsnackbar(const snackbar( content text( 'file saved successfully on back4app', style textstyle(color colors white), ), duration duration(seconds 3), backgroundcolor colors blue, )); } else { print("this is your request error ${apiresponse error}"); } } future\<void> updatedata(string objectid) async { final gamepoint = parseobject('gamepoint') objectid = objectid; // update fields with new values if ( stringcontroller text isnotempty) { gamepoint set('string', stringcontroller text); } if ( doublecontroller text isnotempty) { gamepoint set('double', double parse( doublecontroller text)); } gamepoint set('bool', boolvalue); gamepoint set('date', selecteddate); if ( liststringcontroller text isnotempty) { list\<string> liststringvalue = liststringcontroller text split(',') map((e) => e trim()) tolist(); gamepoint setaddall('liststring', liststringvalue); } if ( listintcontroller text isnotempty) { list\<int> listintvalue = listintcontroller text split(',') map((e) => int parse(e trim())) tolist(); gamepoint setaddunique('listint', listintvalue); } if ( pointercontroller text isnotempty) { gamepoint set('pointer', parsepointer( pointercontroller text)); } if (pickedfile != null) { parsefilebase? parsefile; if (kisweb) { parsefile = parsewebfile(await pickedfile! readasbytes(), name 'file jpg'); } else { parsefile = parsefile(file(pickedfile! path)); } await parsefile save(); gamepoint set('file', parsefile); } // save the updated object var response = await gamepoint save(); if (response success) { scaffoldmessenger of(context) showsnackbar( const snackbar(content text('data updated successfully!')), ); } else { scaffoldmessenger of(context) showsnackbar( snackbar( content text('error updating data ${response error! message}')), ); } } future\<void> incrementfield(string objectid) async { final gamepoint = parseobject('gamepoint') objectid = objectid setincrement('double', 1); await gamepoint save(); } future\<void> decrementfield(string objectid) async { final gamepoint = parseobject('gamepoint') objectid = objectid setdecrement('double', 1); await gamepoint save(); } future\<void> adduniquetolist(string objectid, string value) async { final gamepoint = parseobject('gamepoint') objectid = objectid setaddunique('liststring', value); await gamepoint save(); } future\<void> removefromlist(string objectid, string value) async { final gamepoint = parseobject('gamepoint') objectid = objectid setremove('liststring', value); await gamepoint save(); } future\<void> selectdate(buildcontext context) async { final datetime? picked = await showdatepicker( context context, initialdate selecteddate, firstdate datetime(2000), lastdate datetime(2101), ); if (picked != null && picked != selecteddate) { setstate(() { selecteddate = picked; }); } } future\<void> deletedata(string objectid) async { // delete data logic final parseobject = parseobject('gamepoint') objectid = objectid unset("liststring"); await parseobject save(); } // convert pointer field to a suitable format parseobject parsepointer(string objectid) { // there should be an existing game class with objects final pointer = parseobject('game') objectid = objectid; return pointer; } } this code initializes the parse sdk in flutter, sets up the main application, and displays a simple home page with a title conclusion in this guide, you learned about parseobjects and the various datatypes available to parse you also learned how to handle operations like saving and retrieving the datatypes to and from your back4app backend