Applets: lifecycle

1. What is life cycle

Life cycle refers to the creation of an object from --》 function --》--》 The whole stage of destruction , The emphasis is on a time period

We can Startup of wechat applet , Express The beginning of the life cycle

Close the applet , Indicates the end of the life cycle

The process of running an intermediate applet , Is the life cycle of the applet

2. Classification of life cycle

In the applet , The life cycle is divided into two categories , Namely ：

1. Application life cycle
2. Page lifecycle   

The life cycle range of the page is relatively small , The application life cycle is relatively large

2. What is a life cycle function

  Life cycle function ： It refers to the built-in functions provided by the applet framework , With the life cycle , Automatically execute in order

The function of life cycle function ： Allow programmers to at a specific point in time , Perform certain operations . for example ： When the page is just loaded , Can be in onLoad Initialize the data of the page in the life cycle function

Be careful ： Life cycle emphasizes time period , The life cycle function emphasizes the point in time

2.1 Classification of life cycle functions

1. Apply lifecycle functions

•   It refers to that the applet is starting --》 function --》 Those functions called in turn during destruction
• stay app.js In a statement

• //app.js file 
  App({
      // When the applet is initialized , Execute this function , The trigger of the overall situation is in turn , Can do some initialization work 
      onLaunch:function(options){},
      // Applet startup , Or trigger when you cut into the foreground display from the background 
      onShow:function(options){},
      // Applet startup , Or trigger when you switch from the foreground to the background display 
      onHide:function(){},
  })

1. Page lifecycle function

• On page .js The document states

• Page({
      // Monitor page loading , A page is called only once 
      onLaunch:function(options){},
      // Monitor page display 
      onShow:function(){},
      // Listen for the first rendering of the page , A page is called only once 
      onReady:function(){},
      // Small monitoring page hidden 
      onHide:function(){},
      // Monitor page uninstall , A page is called only once 
      onUnload:function(){},
  })