Set focus on <input> element

You should use HTML autofocus for this:

<input *ngIf="show" #search type="text" autofocus /> 

Note: if your component is persisted and reused, it will only autofocus the first time the fragment is attached. This can be overcome by having a global DOM listener that checks for autofocus attribute inside a DOM fragment when it is attached and then reapplying it or focus via JavaScript.

Here is an example global listener, it only needs to be placed in your spa application once and autofocus will function regardless of how many times the same fragment is reused:

(new MutationObserver(function (mutations, observer) {
    for (let i = 0; i < mutations.length; i++) {
        const m = mutations[i];
        if (m.type == 'childList') {
            for (let k = 0; k < m.addedNodes.length; k++) {
                const autofocuses = m.addedNodes[k].querySelectorAll("[autofocus]"); //Note: this ignores the fragment's root element
                console.log(autofocuses);
                if (autofocuses.length) {
                    const a = autofocuses[autofocuses.length - 1]; // focus last autofocus element
                    a.focus();
                    a.select();
                }
            }
        }
    }
})).observe(document.body, { attributes: false, childList: true, subtree: true });

This directive will instantly focus and select any text in the element as soon as it's displayed. This might require a setTimeout for some cases, it has not been tested much.

import { Directive, ElementRef, OnInit } from '@angular/core';
    
@Directive({
  selector: '[appPrefixFocusAndSelect]',
})
export class FocusOnShowDirective implements OnInit {    
  constructor(private el: ElementRef) {
    if (!el.nativeElement['focus']) {
      throw new Error('Element does not accept focus.');
    }
  }
    
  ngOnInit(): void {
    const input: HTMLInputElement = this.el.nativeElement as HTMLInputElement;
    input.focus();
    input.select();
  }
}

And in the HTML:

<mat-form-field>
  <input matInput type="text" appPrefixFocusAndSelect [value]="'etc'">
</mat-form-field>

html of component:

<input [cdkTrapFocusAutoCapture]="show" [cdkTrapFocus]="show">

controler of component:

showSearch() {
  this.show = !this.show;    
}

..and do not forget about import A11yModule from @angular/cdk/a11y

import { A11yModule } from '@angular/cdk/a11y'

I'm going to weigh in on this (Angular 7 Solution)

input [appFocus]="focus"....

import {AfterViewInit, Directive, ElementRef, Input,} from '@angular/core';

@Directive({
  selector: 'input[appFocus]',
})
export class FocusDirective implements AfterViewInit {

  @Input('appFocus')
  private focused: boolean = false;

  constructor(public element: ElementRef<HTMLElement>) {
  }

  ngAfterViewInit(): void {
    // ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked.
    if (this.focused) {
      setTimeout(() => this.element.nativeElement.focus(), 0);
    }
  }
}

This is working i Angular 8 without setTimeout:

import {AfterContentChecked, Directive, ElementRef} from '@angular/core';

@Directive({
  selector: 'input[inputAutoFocus]'
})
export class InputFocusDirective implements AfterContentChecked {
  constructor(private element: ElementRef<HTMLInputElement>) {}

  ngAfterContentChecked(): void {
    this.element.nativeElement.focus();
  }
}

Explanation: Ok so this works because of: Change detection. It's the same reason that setTimout works, but when running a setTimeout in Angular it will bypass Zone.js and run all checks again, and it works because when the setTimeout is complete all changes are completed. With the correct lifecycle hook (AfterContentChecked) the same result can be be reached, but with the advantage that the extra cycle won't be run. The function will fire when all changes are checked and passed, and runs after the hooks AfterContentInit and DoCheck. If i'm wrong here please correct me.

More one lifecycles and change detection on https://angular.io/guide/lifecycle-hooks

UPDATE: I found an even better way to do this if one is using Angular Material CDK, the a11y-package. First import A11yModule in the the module declaring the component you have the input-field in. Then use cdkTrapFocus and cdkTrapFocusAutoCapture directives and use like this in html and set tabIndex on the input:

<div class="dropdown" cdkTrapFocus cdkTrapFocusAutoCapture>
    <input type="text tabIndex="0">
</div>

We had some issues with our dropdowns regarding positioning and responsiveness and started using the OverlayModule from the cdk instead, and this method using A11yModule works flawlessly.

In Angular, within HTML itself, you can set focus to input on click of a button.

<button (click)="myInput.focus()">Click Me</button>

<input #myInput></input>

To make the execution after the boolean has changed and avoid the usage of timeout you can do:

import { ChangeDetectorRef } from '@angular/core';

constructor(private cd: ChangeDetectorRef) {}

showSearch(){
  this.show = !this.show;  
  this.cd.detectChanges();
  this.searchElement.nativeElement.focus();
}

I'm having same scenario, this worked for me but i'm not having the "hide/show" feature you have. So perhaps you could first check if you get the focus when you have the field always visible, and then try to solve why does not work when you change visibility (probably that's why you need to apply a sleep or a promise)

To set focus, this is the only change you need to do:

your Html mat input should be:

<input #yourControlName matInput>

in your TS class, reference like this in the variables section (

export class blabla...
    @ViewChild("yourControlName") yourControl : ElementRef;

Your button it's fine, calling:

  showSearch(){
       ///blabla... then finally:
       this.yourControl.nativeElement.focus();
}

and that's it. You can check this solution on this post that I found, so thanks to --> https://codeburst.io/focusing-on-form-elements-the-angular-way-e9a78725c04f

There is also a DOM attribute called cdkFocusInitial which works for me on inputs. You can read more about it here: https://material.angular.io/cdk/a11y/overview

Only using Angular Template

<input type="text" #searchText>

<span (click)="searchText.focus()">clear</span>

When using an overlay/dialog, you need to use cdkFocusInitial within cdkTrapFocus and cdkTrapFocusAutoCapture.

CDK Regions:

If you're using cdkFocusInitial together with the CdkTrapFocus directive, nothing will happen unless you've enabled the cdkTrapFocusAutoCapture option as well. This is due to CdkTrapFocus not capturing focus on initialization by default.

In the overlay/dialog component:

<div cdkTrapFocus cdkTrapFocusAutoCapture>
  <input cdkFocusInitial>
</div>

@john-white The reason the magic works with a zero setTimeout is because

this.searchElement.nativeElement.focus();

is sent to the end of the browser callStack and therefore executed last/later, its not a very nice way of getting it to work and it probably means there is other logic in the code that could be improved on.

@ViewChild("input1") inputField: ElementRef;
  
 ngAfterViewInit() {

        this.inputField.nativeElement.focus();

        }

this will auto focus on '#input1' element.

Umut Esen authored an excellent short article on this topic that addresses the problem effectively using Renderer2. Read it here: https://onthecode.co.uk/blog/angular-material-focus-form-input-with-renderer2

He explains this overcomes problems with both Security and Separation of Concerns.

A bit of his code follows:

constructor(private renderer: Renderer2) {}

focusMyInput() {
  this.renderer.selectRootElement('#myInput').focus();
}

Easier way is also to do this.

let elementReference = document.querySelector('<your css, #id selector>');
    if (elementReference instanceof HTMLElement) {
        elementReference.focus();
    }