Orientação a Objetos em Dart: Conceitos Fundamentais

A orientação a objetos é um paradigma amplamente utilizado em muitas linguagens.

[{"selector":"#anim-e4872068-6b61-4490-8307-7c339e842fbd [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(-31.249999886225726%, 0, 0) translate(-25%, 0%) scale(1.5)","translate3d(0%, 0, 0) translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"fill":"forwards"}] [{"selector":"#anim-593cadff-5a0b-4330-b0ae-e669f9f10409","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-39c7d78c-2717-4efc-8227-5ed532d796d6","keyframes":{"transform":["translate3d(115.55555%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}]

O que é Orientação a Objetos?

[{"selector":"#anim-9eaadf38-9bdc-4fc0-b1d3-0f5c8b7f1616 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(18.611111178870015%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-d59567b6-187c-471d-bbc3-3667e1797f02","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-3d203209-cbec-4629-9f3d-7ecf84355119","keyframes":{"transform":["translate3d(-116.02564%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-ffaf8cc6-4b7c-49e2-9b18-f29efb3fee9d","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-911d022e-0ca1-4415-953f-3284fb18a720","keyframes":{"transform":["translate3d(114.64968%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-88c4cfcc-f367-4fa2-958c-8a4abff098cc","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-7929830a-15ce-4564-abda-3f6ebafa7729","keyframes":{"transform":["translate3d(-115.60509%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-92c2a39f-051e-4cc2-a3b0-de4865d2258a","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-af24acc9-464b-4145-8dda-4cf80378a8ae","keyframes":{"transform":["translate3d(115.92356%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] a orientação a objetos é um estilo de programação que se baseia na ideia de que tudo em um programa é tratado como um objeto. Uma classe é uma estrutura que define as características e comportamentos de um objeto. Para criar um objeto, você instancia uma classe, criando uma cópia desse modelo.

Atributos e Métodos

[{"selector":"#anim-d6a81d4e-70ff-40d0-a9c8-d47db3d74280 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(0%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-7e414648-9f87-457a-8fa4-15c2ca8db500","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-817cc6f3-4e1d-48c7-ab85-29eade65414c","keyframes":{"transform":["translate3d(0px, -183.74136%, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-02217799-a764-4f0c-a0cd-6a6f7621916c","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-e44d400c-15ef-4f0d-bf9c-d17343a139fb","keyframes":{"transform":["translate3d(-115.38462%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-b5e80bd3-b911-4c3d-bd44-f9fca86af44f","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-39df51ef-b4f8-4659-9eb9-7bab39e59519","keyframes":{"transform":["translate3d(116.02564%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] Em Dart, eles são definidos dentro da classe e representam as informações que cada objeto pode armazenar. Os métodos, por outro lado, são as ações ou comportamentos que um objeto pode executar.

Encapsulamento

[{"selector":"#anim-f587c409-c708-4524-9394-6b41fe9a4a6e [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(7.812499744007886%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-48ec284d-1d19-4200-b927-fa05c876ee2a","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-be48b3c6-6862-4ad7-b0cb-35f74f5bd3f0","keyframes":{"transform":["translate3d(-115.2381%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-f25fe633-0159-4b36-ba81-5727d7f2341b","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-a9d6b454-6419-405f-8e74-655f1376fc4f","keyframes":{"transform":["translate3d(115.55555%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] ele se refere à ideia de que os atributos de um objeto devem ser protegidos e só devem ser acessados ou modificados por meio de métodos públicos da classe.

Herança

[{"selector":"#anim-c8fa65fd-2438-478d-b328-3117b737e1b7 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(13.705556638319202%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-cfbf83a3-2f2e-4f4d-b494-1b36b0ccf2a0","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-b278a448-4359-414f-84b0-a8d2cb97dd8a","keyframes":{"transform":["translate3d(116.66665%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-d2efebbc-5b19-4460-983c-58f8ee630163","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-8c25e1b4-65b5-4e32-ac25-9047ab187177","keyframes":{"transform":["translate3d(-115.70512%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-694ad13b-7bd5-46dd-8f06-f23bed55fc2f","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-7bd7d092-d0e3-4792-8d30-9cef510ed9f2","keyframes":{"transform":["translate3d(115.92356%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] você pode criar uma nova classe que herda os atributos e métodos de uma classe existente, permitindo reutilização de código e criando hierarquias de classes

Polimorfismo

[{"selector":"#anim-f4d1c349-e9c7-4781-a990-23f451099b73 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(-14.843749786673241%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-154559ec-8b9e-47e3-b823-6ff623f5552a","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-4da2d90d-81b3-476d-96a5-d1908433b3ed","keyframes":{"transform":["translate3d(-115.2381%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-af38a5f0-77ec-4e67-9810-9be5f8719f02","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-b16d5b84-f2ba-4ae1-b932-97aa404ec4bd","keyframes":{"transform":["translate3d(114.92064%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] O polimorfismo é a capacidade de um objeto se comportar de maneiras diferentes com base no contexto em que é usado.

Mais sobre Polimorfismo

[{"selector":"#anim-f37291f0-677a-4cb8-82eb-1e0b8616ab1c [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(-8.71212125537425%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-90cc3ccc-ad98-46db-98ea-03023261c150","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-d493969a-9892-4ea4-bc21-8f4e29dae669","keyframes":{"transform":["translate3d(-114.8265%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-18b4b1c2-5b0b-4ce9-bbd0-0aef3a276291","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-ac93b484-fd3d-4cf1-ae14-08dcb7292a8d","keyframes":{"transform":["translate3d(115.87301%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-554bc1b2-3011-4165-927f-262ceef82d01","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-4cee53c3-9f42-49ee-bff6-5543cbcad821","keyframes":{"transform":["translate3d(-114.92064%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] O polimorfismo torna o código mais flexível e extensível, permitindo que novas classes sejam adicionadas ao programa sem afetar o comportamento existente.

Continue aprendendo

[{"selector":"#anim-ec7baba5-bcdf-4fd1-b971-274d9555743f [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(16.666666727346282%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-b5da3673-f9f8-41cb-89d1-95593acc4343","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-18e03955-0301-4287-9859-1dff2be1b760","keyframes":{"transform":["translate3d(-115.2381%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-ebc03606-76f6-48b9-9868-6e81ce57c12d","keyframes":{"opacity":[0,1]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] [{"selector":"#anim-41937768-ad70-4b5d-b6fb-92946cb3c649","keyframes":{"transform":["translate3d(115.55555%, 0px, 0)","translate3d(0px, 0px, 0)"]},"delay":0,"duration":600,"easing":"cubic-bezier(0.2, 0.6, 0.0, 1)","fill":"both"}] Confira mais detalhes e mais atalhos em nosso artigo completo . É só clicar abaixo ! Clique aqui!