Saznajte kako stvoriti svoju prvu Angular aplikaciju za 20 minuta

Angular je JavaScript okvir, koji je stvorio moj Misko Hevery i održava ga Google. To je MVC (Model View Vontroller). Možete posjetiti službenu stranicu kako biste saznali više o njoj.

Trenutno je najnovija verzija Angulala 5.2.10. Postoje prva generacija 1.x i druga generacija 2.x, a dvije generacije su potpuno različite u svojim strukturama i metodama. Ne brinite ako se osjećate zbunjeno zbog verzije jer ćemo u ovom članku koristiti drugu generaciju 2.x.

Sadržaj

  • Dodavanje stavke (naučite kako poslati obrazac u Angular-u)
  • Uklanjanje stavke (naučite kako dodati događaj u Angular)
  • Kutna animacija (naučite kako animirati komponente)

Preduvjeti:

  • Node.js

Provjerite je li node.js instaliran na vašem računalu. Saznajte više o instalaciji.

  • npm

npm (upravitelj paketa čvorova) instaliran je s Node.js

Provjerite verziju node.js :

node -v

npm:

npm -v

Kutni-CLI

Trebali biste imati najnoviju verziju Angular-CLI. Saznajte više o Kutna CLI ovdje , i naći upute za instalaciju.

Instalirajte Angular-cli:

npm install -g @angular/cli

I na kraju, trebali biste imati:

  • Osnovno znanje JavaScript-a
  • Osnove HTML-a i CSS-a

Ne morate imati nikakvo znanje o Angular-u.

Sad kad imamo okruženje za pokretanje naše aplikacije Angular, krenimo!

Izrada naše prve aplikacije

Upotrijebit ćemo angular-cli za stvaranje i generiranje naših komponenata. Generirat će usluge, usmjerivač, komponente i direktive.

Da biste stvorili novi Angular projekt s Angular-cli, jednostavno pokrenite:

ng new my-app

Projekt će se generirati automatski. Stvorimo našu aplikaciju za obveze!

ng new todo-app

Zatim otvorite datoteke u uređivaču teksta. Koristim uzvišeni tekst, ali možete odabrati bilo kojeg uređivača.

Evo kako izgleda struktura aplikacije:

Ne brinite ako ste zbunjeni datotekama. Sav naš rad bit će u mapi aplikacije . Sadrži pet datoteka:

Napomena: Angular 2 koristi TypeScript u kojem datoteke završavaju s nastavkom " .ts" .

Da bismo napravili lijepo sučelje za našu aplikaciju, upotrijebit ćemo Bootstrap 4 Framework.

Uključite cdn bootstrapa u index.html :

Pokrenite aplikaciju na svom terminalu:

ng serve

Aplikacija će raditi u // localhost: 4200 /

Sve je dobro ?!

Sad ćemo napraviti HTML strukturiranje. Mi ćemo koristiti Bootstrap klase za stvaranje jednostavnog obrasca.

app.component.html :

Todo App

Add

U app.component.css :

body{ padding: 0; margin: 0;
}form{ max-width: 25em; margin: 1em auto;}

Da bismo uhvatili ulaznu vrijednost u Angular 2, možemo koristiti ngModel direktivu. Možete unijeti varijablu kao atribut unutar ulaznog elementa.

Da biste stvorili varijablu kao atribut, upotrijebite # nakon čega slijedi ime varijable.

// get the value of the Variable

{{myVariable.value}}

Sada nabavite vrijednost varijable "todo":

{{todo.value}}

Sve je dobro ?!

Sada moramo pohraniti vrijednost zabilježenu iz unosa. Možemo stvoriti prazan niz u app.component.ts unutar klase AppComponent:

export class AppComponent { todoArray=[] }

Zatim na naš gumb moramo dodati događaj klika koji potiskuje zabilježenu vrijednost u " todoArray ".

app.component.html :

Add

U app.component.ts :

export class AppComponent { todoArray=[]
addTodo(value){ this.todoArray.push(value) console.log(this.todos) } }
Upotrijebite console.log (this.todoArray) da biste vidjeli vrijednost Arraya

Dohvaćanje podataka iz "todoArray"

Now we have to fetch data stored in “todosArray.” We will use the *ngFor directive to loop through the array and extract the data.

app.component.html:

  • {{todo}}

After fetching data:

The data will now be fetched automatically when we click the add button.

Styling the app

I like to use Google-fonts and Material-icons, which are free to use.

Include Google fonts inside app.component.css:

/*Google fonts*/@import url('//fonts.googleapis.com/css?family=Raleway');

And Material-icons inside index.html:

After adding some styling to our app, it will look like this:

To use Material icons:

iconName

Add “delete” and “add” icons in app.component.html:

// put add icon inside "input-group-text" div
add
// and delete icon inside list item 
  • {{todo}}delete
  • For styles in app.component.css:

    /*Google fonts*/@import url('//fonts.googleapis.com/css?family=Raleway');
    body{ padding: 0; margin: 0;
    }form{ max-width: 30em; margin: 4em auto; position: relative; background: #f4f4f4; padding: 2em 3em;}form h1{ font-family: "Raleway"; color:#F97300; }form input[type=text]::placeholder{ font-family: "Raleway"; color:#666; }form .data{ margin-top: 1em;}form .data li{ background: #fff; border-left: 4px solid #F97300; padding: 1em; margin: 1em auto; color: #666; font-family: "Raleway";}form .data li i{ float: right; color: #888; cursor: pointer;}form .input-group-text{ background: #F97300; border-radius: 50%; width: 5em; height: 5em; padding: 1em 23px; color: #fff; position: absolute; right: 13px; top: 68px; cursor: pointer;}form .input-group-text i{ font-size: 2em;}form .form-control{ height: 3em; font-family: "Raleway";}form .form-control:focus{ box-shadow: 0;}

    Our app is almost done, but we need to add some features. A delete functionality should let users click a delete icon and delete an item. It would also be great to have the option to enter a new item with the return key, instead of clicking the add button.

    Deleting items

    To add the delete functionality, we will use the “splice” array method and a for loop. We will loop through “todoarray” and extract the item we want to delete.

    Add a (click) event to delete icon and give it “todo” as parameter :

  • {{todo}} delete
  • In app.component.ts:

    /*delete item*/ deleteItem(){ console.log("delete item") }

    When you click delete, this should show up in the console:

    Now we have to loop through “todoArray” and splice the item we clicked.

    In app.component.ts:

    /*delete item*/ deleteItem(todo){ for(let i=0 ;i<= this.todoArray.length ;i++){ if(todo== this.todoArray[i]){ this.todoArray.splice(i,1) } } }

    The result:

    Awesome ?!!

    Entering to add items

    We can add a submit event to the form:

    (ngSubmit)="TodoSubmit()"

    We need to add the variable “#todoForm” to the form and give it “ngForm” as a value. In this case, we just have one field so we will just get a single value. If we have multiple fields, the submit event will return the values of all the fields in the form.

    app.component.html

    in app.component.ts

    // submit Form todoSubmit(value:any){ console.log(value) }

    Check the console. It will return an object of values:

    So now we have to push the returned value to “todoArray”:

    // submit Form todoSubmit(value:any){ if(value!==""){ this.todoArray.push(value.todo) //this.todoForm.reset() }else{ alert('Field required **') } }

    Here we are ?. The value is inserted without needing to click the add button, just by clicking “enter”:

    One more thing. To reset the the form after submitting, add the “resetForm()” build-in method to submit the event.

    The form will reset after each submit now:

    Adding animations

    I like to add a little touch of animations. To add animation, import the animations components in your app.component.ts:

    import { Component,trigger,animate,style,transition,keyframes } from '@angular/core';

    Then add the animations property to “@component” decorator:

    @Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'], animations:[ trigger("moveInLeft",[ transition("void=> *",[style({transform:"translateX(300px)"}), animate(200,keyframes([ style({transform:"translateX(300px)"}), style({transform:"translateX(0)"}) ]))]),
    transition("*=>void",[style({transform:"translateX(0px)"}), animate(100,keyframes([ style({transform:"translateX(0px)"}), style({transform:"translateX(300px)"}) ]))]) ])
    ]})

    Now the items have a nice effect when they’re entered and deleted.

    All the code

    app.component.ts

    import { Component,trigger,animate,style,transition,keyframes } from '@angular/core';
    @Component({ selector: 'app-root', templateUrl: './app.component.html', styleUrls: ['./app.component.css'], animations:[ trigger("moveInLeft",[ transition("void=> *",[style({transform:"translateX(300px)"}), animate(200,keyframes([ style({transform:"translateX(300px)"}), style({transform:"translateX(0)"}) ]))]),
    transition("*=>void",[style({transform:"translateX(0px)"}), animate(100,keyframes([ style({transform:"translateX(0px)"}), style({transform:"translateX(300px)"}) ]))]) ])
    ]})export class AppComponent { todoArray=[]; todo; //todoForm: new FormGroup()
    addTodo(value){ if(value!==""){ this.todoArray.push(value) //console.log(this.todos) }else{ alert('Field required **') } }
    /*delete item*/ deleteItem(todo){ for(let i=0 ;i<= this.todoArray.length ;i++){ if(todo== this.todoArray[i]){ this.todoArray.splice(i,1) } } }
    // submit Form todoSubmit(value:any){ if(value!==""){ this.todoArray.push(value.todo) //this.todoForm.reset() }else{ alert('Field required **') } } }

    app.component.html

    Todo App

    add
    • {{todo}} delete

    app.component.css

    /*Google fonts*/@import url('//fonts.googleapis.com/css?family=Raleway');
    body{ padding: 0; margin: 0;
    }form{ max-width: 30em; margin: 4em auto; position: relative; background: #f4f4f4; padding: 2em 3em; overflow: hidden;}form h1{ font-family: "Raleway"; color:#F97300; }form input[type=text]::placeholder{ font-family: "Raleway"; color:#666; }form .data{ margin-top: 1em;}form .data li{ background: #fff; border-left: 4px solid #F97300; padding: 1em; margin: 1em auto; color: #666; font-family: "Raleway";}form .data li i{ float: right; color: #888; cursor: pointer;}form .input-group-text{ background: #F97300; border-radius: 50%; width: 5em; height: 5em; padding: 1em 23px; color: #fff; position: absolute; right: 13px; top: 68px; cursor: pointer;}form .input-group-text i{ font-size: 2em;}form .form-control{ height: 3em; font-family: "Raleway";}form .form-control:focus{ box-shadow: 0;}

    We are done ?. You can find the files and code on Github.

    See the Demo

    Conclusion

    Angular is easier than you think. Angular is one of the best JavaScript libraries, and it has great support and a nice community. It also has tools that make working with Angular fast and easy, like Angular-cli.

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    Here are some of the best online courses to learn Angular for free:

    Angular 1.x

    • Shaping with Angular
    • Learn Angular

    Angular 2.x (recommended)

    • learn Angular2 (coursetro)
    • YouTube playlist