Page Components

Every Taro application includes at least one page component, which can jump through Taro routes and also access the lifecycle of the mini program page.

Example Code

Class Component

page.js

import React, { Component } from 'react'
import { View } from '@tarojs/components'

class Index extends Component {
  // All React component methods can be used
  componentDidMount () {}

  // onLoad
  onLoad () {}

  // onReady
  onReady () {}

  // onShow
  componentDidShow () {}

  // onHide
  componentDidHide () {}

  // onPullDownRefresh，except for componentDidShow/componentDidHide
  // All page lifecycle function names correspond to mini program
  onPullDownRefresh () {}

  render () {
    return (
      <View className='index' />
    )
  }
}

export default Index

Functional Component

page.js

import React, { useEffect } from 'react'
import { View } from '@tarojs/components'
import {
  useReady,
  useDidShow,
  useDidHide,
  usePullDownRefresh
} from '@tarojs/taro'

function Index () {
  // All React Hooks can be used
  useEffect(() => {})

  // onReady
  useReady(() => {})

  // onShow
  useDidShow(() => {})

  // onHide
  useDidHide(() => {})

  // Taro implements custom React Hooks for all mini program page lifecycles to support
  usePullDownRefresh(() => {})

  return (
    <View className='index' />
  )
}

export default Index

Page component configuration

Please refer to the page configuration

Lifecycle

In addition to supporting React's lifecycle methods, page components additionally support the following lifecycles, in accordance with mini program standards.

onLoad (options)

onLoad of the corresponding page in the mini program.

Page routing parameters can be accessed during this lifecycle by accessing the options parameter or by calling getCurrentInstance().router.

onReady ()

onReady of the corresponding page in the mini program.

This lifecycle begins with access to the DOM nodes of the mini program rendering layer using APIs such as createCanvasContext or createSelectorQuery.

The onReady of the child component

The onReady lifecycle is only triggered for page components. Child components can use Taro's built-in Message System to listen to the onReady() lifecycle of the page component.

A child component in a page

import React from 'react'
import { View } from '@tarojs/components'
import Taro, { eventCenter, getCurrentInstance } from '@tarojs/taro'

class Test extends React.Component {
  $instance = getCurrentInstance()

  componentWillMount () {
    const onReadyEventId = this.$instance.router.onReady
    eventCenter.once(onReadyEventId, () => {
      console.log('onReady')

      // onReady is triggered to get the node of the rendering layer of the mini program
      Taro.createSelectorQuery().select('#only')
        .boundingClientRect()
        .exec(res => console.log(res, 'res'))
    })
  }

  render () {
    return (
      <View id="only">
      </View>
    )
  }
}

But when the child component is load-on-demand, the page onReady has already been triggered. If this on-demand subcomponent needs to get the DOM node of the rendering layer of the mini program because it missed the page onReady, it can only try to simulate it using Taro.nextTick.

Load-on-demand subcomponents

import React from 'react'
import { View } from '@tarojs/components'
import Taro from '@tarojs/taro'

class Test extends React.Component {
  componentDidMount () {
    Taro.nextTick(() => {
        // Use Taro.nextTick to simulate that setData has ended and the node has finished rendering      Taro.createSelectorQuery().select('#only')
        .boundingClientRect()
        .exec(res => console.log(res, 'res'))
    })
  }

  render () {
    return (
      <View id="only" />
    )
  }
}

componentDidShow ()

onShow of the corresponding page in the mini program.

Triggered when the page is displayed/entered in the foreground.

The onShow of the Subcomponents

The onShow lifecycle is only triggered for page components. Subcomponents can use Taro's built-in message system to listen to the onShow() lifecycle of the page component.

A sub-component of the page

import React from 'react'
import { View } from '@tarojs/components'
import { eventCenter, getCurrentInstance } from '@tarojs/taro'

class Test extends React.Component {
  $instance = getCurrentInstance()

  componentWillMount () {
    const onShowEventId = this.$instance.router.onShow
    eventCenter.on(onShowEventId, this.onShow)
  }

  componentWillUnmount () {
    const onShowEventId = this.$instance.router.onShow
    eventCenter.off(onShowEventId, this.onShow)
  }

  onShow = () => {
    console.log('onShow')
  }

  render () {
    return (
      <View id="only" />
    )
  }
}

componentDidHide ()

onHide of the corresponding page in the mini program.

Triggered when the page is hidden/entered in the background.

The onHide of a subcomponent

The onHide lifecycle is only triggered for page components. Subcomponents can use Taro's built-in message system to listen to the onHide() lifecycle of the page component.

A sub-component of the page

import React from 'react'
import { View } from '@tarojs/components'
import { eventCenter, getCurrentInstance } from '@tarojs/taro'

class Test extends React.Component {
  $instance = getCurrentInstance()

  componentWillMount () {
    const onHideEventId = this.$instance.router.onHide
    eventCenter.on(onHideEventId, this.onHide)
  }

  componentWillUnmount () {
    const onHideEventId = this.$instance.router.onHide
    eventCenter.off(onHideEventId, this.onHide)
  }

  onHide = () => {
    console.log('onHide')
  }

  render () {
    return (
      <View id="only" />
    )
  }
}

onPullDownRefresh ()

Listen to the user drop-down action.

• You need to set it in the window option of the global configuration or in the page configuration enablePullDownRefresh: true.
• The pull-down refresh can be triggered by Taro.startPullDownRefresh, which triggers the pull-down refresh animation after the call, and the effect is the same as the user's manual pull-down refresh.
• When the data has been processed and refreshed, Taro.stopPullDownRefresh You can stop the drop-down refresh of the current page.

onReachBottom ()

Listen to the user pull-up bottoming event.

• The trigger distance can be set in the window option of the global configuration or in the page configuration onReachBottomDistance。
• This event will only be triggered once during the slide within the trigger distance

H5 does not have synchronization for now, you can simulate it by binding scroll events to window

onPageScroll (Object)

Listening to user swipe page events

H5 does not have synchronization for now, you can simulate it by binding scroll events to window

Parameters

Object

Parameters	Type	Description
scrollTop	Number	The distance the page has scrolled in the vertical direction (unit: px)

onAddToFavorites (Object)

Listen to the user's click on the "Favorites" button in the upper-right corner of the menu and customize the contents of the favorites.

Supported by Taro 3.0.3 and above. Only supported by WeChat mini program , this interface is Beta version, supported from Android version 7.0.15, only supported in Android platform for now.

Parameters

Object

Parameters	Type	Description
webviewUrl	String	If the page contains a web-view component, the url of the current web-view is returned

This event handler requires the return of an Object, which is used to customize the contents of the collection.

Fields	Description	Default
title	Customized Title	Page title or account name
imageUrl	Customize the image, displaying it with an aspect ratio of 1:1	Page Screenshot
query	Custom query fields	Current page query

Example Code

page.js

onAddToFavorites (res) {
  // webview  page return webviewUrl
  console.log('WebviewUrl: ', res?.webviewUrl)
  return {
    title: 'custom title',
    imageUrl: 'https://demo.png',
    query: 'name=xxx&age=xxx',
  }
}

onShareAppMessage (Object)

Listen to the user's behavior when they click on the forward button (Button component openType='share') or the "Forward" button in the top-right menu, and customize the forwarding content.

Attention:

1. When onShareAppMessage is not triggered, please set enableShareAppMessage: true in the page config
2. Only if this event handler is defined, the "Forward" button will be displayed in the upper right menu

Parameters

Object

Parameters	Type	Description
from	String	Forwarding event sources button: In-page forwarding buttons. menu: Top right corner forwarding menu
target	Object	If the from value is button, then target is the button that triggered the forwarding event, otherwise it is undefined
webViewUrl	String	Returns the url of the current WebView if the page contains a WebView component

This event requires the return of an Object, which is used to customize the forwarding content, and returns the following:

Custom forwarding content

Fields	Type	Description
title	Forwarding Title	Current mini program name
path	Forwarding Title	Current page path, must be a full path starting with /
imageUrl	Custom image path, either local file path, package file path or network image path. Support PNG and JPG. Display image aspect ratio is 5:4	Use default screenshot

Example Code

page.js

export default class Index extends Component {
  onShareAppMessage (res) {
    if (res.from === 'button') {
      // From the on-page forward button
      console.log(res.target)
    }
    return {
      title: 'Custom forwarding title',
      path: '/page/user?id=123'
    }
  }
}

page.config.js

export default {
  // When `onShareAppMessage` is not triggered, you can try to configure this option
  enableShareAppMessage: true
}

onShareTimeline ()

Listen to the behavior of the "Share to moments" button in the top-right menu and customize the sharing content.

Taro version 3.0.3 and above support Only WeChat mini program are supported, the base library 2.11.3 starts to support, this interface is a Beta version, only supported in Android platform for now

Attention:

1. When onShareAppMessage is not triggered, please set enableShareAppMessage: true in the page config
2. Only if this event handler is defined, the "Forward" button will be displayed in the upper right menu

Return Values

The event handler function can return an Object for customizing the shared content, does not support custom page paths, and returns the following content.

Fields	Description	Defalut
title	Custom title	Current mini program name
query	The parameters carried in the custom page path	The parameters carried in the current page path
imageUrl	Custom image path, can be local file or network image. Support PNG and JPG, display image aspect ratio is 1:1.	default use mini program Logo

Example Code

page.js

class Index extends Component {
  onShareAppMessage () {}
  onShareTimeline () {
    console.log('onShareTimeline')
    return {}
  }
}

page.config.js

export default {
  // When `onShareAppMessage` is not triggered, you can try to configure this option
  enableShareAppMessage: true,
  // When `onShareTimeline` is not triggered, you can try to configure this option
  enableShareTimeline: true
}

onResize (Object)

Triggered when the mini program screen is rotated. For details, see Response to display area changes。

onTabItemTap (Object)

Triggered when the tab is clicked.

Parameters

Object

Parameters	Type	Description
index	String	The serial number of the clicked tabItem, starting from 0
pagePath	String	The path to the page where the tabItem was clicked
text	String	The text of the clicked tabItem's button

onTitleClick ()

Only Alipay mini program support

Click on the title to trigger

onOptionMenuClick ()

Only Alipay mini program support

Triggered by clicking on additional icons in the navigation bar

onPopMenuClick ()

Only Alipay mini program support

No description yet

onPullIntercept ()

Only Alipay mini program support

Triggered on dropdown truncation