ionic-framework/core/src/components/loading/readme.md

ion-loading

An overlay that can be used to indicate activity while blocking user interaction. The loading indicator appears on top of the app's content, and can be dismissed by the app to resume user interaction with the app. It includes an optional backdrop, which can be disabled by setting showBackdrop: false upon creation.

Dismissing

The loading indicator can be dismissed automatically after a specific amount of time by passing the number of milliseconds to display it in the duration of the loading options. To dismiss the loading indicator after creation, call the dismiss() method on the loading instance. The onDidDismiss function can be called to perform an action after the loading indicator is dismissed.

Customization

Loading uses scoped encapsulation, which means it will automatically scope its CSS by appending each of the styles with an additional class at runtime. Overriding scoped selectors in CSS requires a higher specificity selector.

We recommend passing a custom class to cssClass in the create method and using that to add custom styles to the host and inner elements. This property can also accept multiple classes separated by spaces. View the Usage section for an example of how to pass a class using cssClass.

/* DOES NOT WORK - not specific enough */
ion-loading {
  color: green;
}

/* Works - pass "my-custom-class" in cssClass to increase specificity */
.my-custom-class {
  color: green;
}

Any of the defined CSS Custom Properties can be used to style the Loading without needing to target individual elements:

.my-custom-class {
  --background: #222;
  --spinner-color: #fff;

  color: #fff;
}

If you are building an Ionic Angular app, the styles need to be added to a global stylesheet file. Read Style Placement in the Angular section below for more information.

Usage

Angular

import { Component } from '@angular/core';
import { LoadingController } from '@ionic/angular';

@Component({
  selector: 'loading-example',
  templateUrl: 'loading-example.html',
  styleUrls: ['./loading-example.css']
})
export class LoadingExample {
  constructor(public loadingController: LoadingController) {}

  async presentLoading() {
    const loading = await this.loadingController.create({
      cssClass: 'my-custom-class',
      message: 'Please wait...',
      duration: 2000
    });
    await loading.present();

    const { role, data } = await loading.onDidDismiss();
    console.log('Loading dismissed!');
  }

  async presentLoadingWithOptions() {
    const loading = await this.loadingController.create({
      spinner: null,
      duration: 5000,
      message: 'Click the backdrop to dismiss early...',
      translucent: true,
      cssClass: 'custom-class custom-loading',
      backdropDismiss: true
    });
    await loading.present();

    const { role, data } = await loading.onDidDismiss();
    console.log('Loading dismissed with role:', role);
  }
}

Style Placement

In Angular, the CSS of a specific page is scoped only to elements of that page. Even though the Loading can be presented from within a page, the ion-loading element is appended outside of the current page. This means that any custom styles need to go in a global stylesheet file. In an Ionic Angular starter this can be the src/global.scss file or you can register a new global style file by adding to the styles build option in angular.json.

Javascript

async function presentLoading() {
  const loading = document.createElement('ion-loading');

  loading.cssClass = 'my-custom-class';
  loading.message = 'Please wait...';
  loading.duration = 2000;

  document.body.appendChild(loading);
  await loading.present();

  const { role, data } = await loading.onDidDismiss();
  console.log('Loading dismissed!');
}

async function presentLoadingWithOptions() {
  const loading = document.createElement('ion-loading');

  loading.spinner = null;
  loading.duration = 5000;
  loading.message = 'Click the backdrop to dismiss early...';
  loading.translucent = true;
  loading.cssClass = 'custom-class custom-loading';
  loading.backdropDismiss = true;

  document.body.appendChild(loading);
  await loading.present();

  const { role, data } = await loading.onDidDismiss();
  console.log('Loading dismissed with role:', role);
}

React

/* Using with useIonLoading Hook */

import React from 'react';
import { IonButton, IonContent, IonPage, useIonLoading } from '@ionic/react';

interface LoadingProps {}

const LoadingExample: React.FC<LoadingProps> = () => {
  const [present] = useIonLoading();
  return (
    <IonPage>
      <IonContent>
        <IonButton
          expand="block"
          onClick={() =>
            present({
              duration: 3000,
            })
          }
        >
          Show Loading
        </IonButton>
        <IonButton
          expand="block"
          onClick={() => present('Loading', 2000, 'dots')}
        >
          Show Loading using params
        </IonButton>
      </IonContent>
    </IonPage>
  );
};

/* Using with IonLoading Component */

import React, { useState } from 'react';
import { IonLoading, IonButton, IonContent } from '@ionic/react';

export const LoadingExample: React.FC = () => {
  const [showLoading, setShowLoading] = useState(true);

  setTimeout(() => {
    setShowLoading(false);
  }, 2000);

  return (
    <IonContent>
      <IonButton onClick={() => setShowLoading(true)}>Show Loading</IonButton>
      <IonLoading
        cssClass='my-custom-class'
        isOpen={showLoading}
        onDidDismiss={() => setShowLoading(false)}
        message={'Please wait...'}
        duration={5000}
      />
    </IonContent>
  );
};

Stencil

import { Component, h } from '@stencil/core';

import { loadingController } from '@ionic/core';

@Component({
  tag: 'loading-example',
  styleUrl: 'loading-example.css'
})
export class LoadingExample {
  async presentLoading() {
    const loading = await loadingController.create({
      cssClass: 'my-custom-class',
      message: 'Please wait...',
      duration: 2000
    });
    await loading.present();

    const { role, data } = await loading.onDidDismiss();
    console.log('Loading dismissed!', role, data);
  }

  async presentLoadingWithOptions() {
    const loading = await loadingController.create({
      spinner: null,
      duration: 5000,
      message: 'Click the backdrop to dismiss early...',
      translucent: true,
      cssClass: 'custom-class custom-loading',
      backdropDismiss: true
    });
    await loading.present();

    const { role, data } = await loading.onDidDismiss();
    console.log('Loading dismissed with role:', role, data);
  }

  render() {
    return [
      <ion-content>
        <ion-button onClick={() => this.presentLoading()}>Present Loading</ion-button>
        <ion-button onClick={() => this.presentLoadingWithOptions()}>Present Loading: Options</ion-button>
      </ion-content>
    ];
  }
}

Vue

<template>
  <ion-button @click="presentLoading">Show Loading</ion-button>
  <br />
  <ion-button @click="presentLoadingWithOptions">Show Loading</ion-button>
</template>

<script>

<script>
import { IonButton, loadingController } from '@ionic/vue';
import { defineComponent } from 'vue';

export default defineComponent({
  props: {
    timeout: { type: Number, default: 1000 },
  },
  methods: {
    async presentLoading() {
      const loading = await loadingController
        .create({
          cssClass: 'my-custom-class',
          message: 'Please wait...',
          duration: this.timeout,
        });
        
      await loading.present();
      
      setTimeout(function() {
        loading.dismiss()
      }, this.timeout);
    },
    async presentLoadingWithOptions() {
      const loading = await loadingController
        .create({
          spinner: null,
          duration: this.timeout,
          message: 'Click the backdrop to dismiss early...',
          translucent: true,
          cssClass: 'custom-class custom-loading',
          backdropDismiss: true
        });
        
      await loading.present();
        
      setTimeout(function() {
        loading.dismiss()
      }, this.timeout);
    },
  },
  components: { IonButton }
});
</script>

Developers can also use this component directly in their template:

<template>
  <ion-button @click="setOpen(true)">Show Loading</ion-button>
  <ion-loading
    :is-open="isOpenRef"
    cssClass="my-custom-class"
    message="Please wait..."
    :duration="timeout"
    @onDidDismiss="setOpen(false)"
  >
  </ion-loading>
</template>

<script>
import { IonLoading, IonButton } from '@ionic/vue';
import { defineComponent, ref } from 'vue';

export default defineComponent({
  props: {
    timeout: { type: Number, default: 1000 },
  },
  components: { IonLoading, IonButton },
  setup() {
    const isOpenRef = ref(false);
    const setOpen = (state: boolean) => isOpenRef.value = state;
    
    return { isOpenRef, setOpen }
  }
});
</script>

Properties

Property	Attribute	Description	Type	Default
animated	animated	If true, the loading indicator will animate.	boolean	true
backdropDismiss	backdrop-dismiss	If true, the loading indicator will be dismissed when the backdrop is clicked.	boolean	false
cssClass	css-class	Additional classes to apply for custom CSS. If multiple classes are provided they should be separated by spaces.	string | string[] | undefined	undefined
duration	duration	Number of milliseconds to wait before dismissing the loading indicator.	number	0
enterAnimation	--	Animation to use when the loading indicator is presented.	((baseEl: any, opts?: any) => Animation) | undefined	undefined
keyboardClose	keyboard-close	If true, the keyboard will be automatically dismissed when the overlay is presented.	boolean	true
leaveAnimation	--	Animation to use when the loading indicator is dismissed.	((baseEl: any, opts?: any) => Animation) | undefined	undefined
message	message	Optional text content to display in the loading indicator.	IonicSafeString | string | undefined	undefined
mode	mode	The mode determines which platform styles to use.	"ios" | "md"	undefined
showBackdrop	show-backdrop	If true, a backdrop will be displayed behind the loading indicator.	boolean	true
spinner	spinner	The name of the spinner to display.	"bubbles" | "circles" | "circular" | "crescent" | "dots" | "lines" | "lines-small" | null | undefined	undefined
translucent	translucent	If true, the loading indicator will be translucent. Only applies when the mode is "ios" and the device supports backdrop-filter.	boolean	false

Events

Event	Description	Type
ionLoadingDidDismiss	Emitted after the loading has dismissed.	CustomEvent<OverlayEventDetail<any>>
ionLoadingDidPresent	Emitted after the loading has presented.	CustomEvent<void>
ionLoadingWillDismiss	Emitted before the loading has dismissed.	CustomEvent<OverlayEventDetail<any>>
ionLoadingWillPresent	Emitted before the loading has presented.	CustomEvent<void>

Methods

dismiss(data?: any, role?: string | undefined) => Promise<boolean>

Dismiss the loading overlay after it has been presented.

Returns

Type: Promise<boolean>

onDidDismiss<T = any>() => Promise<OverlayEventDetail<T>>

Returns a promise that resolves when the loading did dismiss.

Returns

Type: Promise<OverlayEventDetail<T>>

onWillDismiss<T = any>() => Promise<OverlayEventDetail<T>>

Returns a promise that resolves when the loading will dismiss.

Returns

Type: Promise<OverlayEventDetail<T>>

present() => Promise<void>

Present the loading overlay after it has been created.

Returns

Type: Promise<void>

CSS Custom Properties

Name	Description
--backdrop-opacity	Opacity of the backdrop
--background	Background of the loading dialog
--height	Height of the loading dialog
--max-height	Maximum height of the loading dialog
--max-width	Maximum width of the loading dialog
--min-height	Minimum height of the loading dialog
--min-width	Minimum width of the loading dialog
--spinner-color	Color of the loading spinner
--width	Width of the loading dialog

Dependencies

Depends on

• ion-backdrop
• ion-spinner

Graph

graph TD;
  ion-loading --> ion-backdrop
  ion-loading --> ion-spinner
  style ion-loading fill:#f9f,stroke:#333,stroke-width:4px

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