WeChat program Registration program App() function

App

App()

App() function is used to register a small program. Accepts an object parameter that specifies the life cycle function of a small program, and so on.

Object parameter description:

Fore desk, background definition: When the user clicks on the upper left corner to close, or press the device Home key to leave WeChat, the small program is not directly destroyed, but into the background; It is important to note that only when a small program enters the background for a certain amount of time, or if the system resources are too high, will it be truly destroyed.

Close the applet (the base library version 1.1.0 start support): When the user is scanned, forwarding the entrance ( Scene It is 1007, 1008, 1011, 1025) to enter the applet, and if you don't have a small procedure, the applet will be destroyed. The small program running mechanism changes in the base library version 1.4.0 : The last closing logic is not applicable in the new version, Detail

Sample code:

App({
  onLaunch: function(options) { 
    // Do something initial when launch.
  },
  onShow: function(options) {
      // Do something when show.
  },
  onHide: function() {
      // Do something when hide.
  },
  onError: function(msg) {
    console.log(msg)
  },
  globalData: 'I am global data'
})

onLaunch, onShow parameter

Scene values See in detail.

The following scenarios support returning to the referrerInfo.appId:

onPageNotFound

Base library 1.9.90 starts to support, and low versions need to be compatible

When the page you want to open does not exist, the listener is recalled with the following information:

Developers can redirect processing in the onPageNotFound callback, but must synchronize processing in the callback, and asynchronous processing, such as setTimeout asynchronous execution, is not valid.

Example code:

App({
  onPageNotFound(res) {
    wx.redirectTo({
      url: 'pages/...'
    })
  }
})

Attention:

1. WeChat developer tools do not support onPageNotFound debugging at this time, please use real-world debugging
2. If the developer does not add onPageNotFound listening, when the jump page does not exist, the page that is pushed into the WeChat client's native page does not have a prompt page
3. If the onPageNotFound callback is redirected to another page that does not exist, the page that is pushed into the WeChat client's native does not have a prompt page, and there is no callback onPageNotFound

getApp()

We provide a global getApp() that can get instances of small programs.

// other.js
var appInstance = getApp()
console.log(appInstance.globalData) // I am global data

Attention:

App() be registered .js the app's website and cannot be registered more than one.

Instead of calling App() in functions getApp() use this get the app instance.

Do not call getCurrentPage() generated.

getApp() functions privately after getting an instance through getApp().