書名： React Native Blueprints
作者名： Emilio Rodriguez Martinez
本章字?jǐn)?shù)： 147字
更新時(shí)間： 2021-07-02 15:19:58

Adding state to our screen

Let's add some initial state to our ShoppingList screen to populate the list with actual dynamic data. We will start by creating a constructor and setting the initial state there:

/*** ShoppingList.js ***/

...
constructor(props) {
  super(props);
  this.state = {
    products: [{ id: 1, name: 'bread' }, { id: 2, name: 'eggs' }]
  };
}
...

Now, we can render that state inside of <List> (inside the render method):

/*** ShoppingList.js ***/

...
<List>
 {
   this.state.products.map(p => {
     return (
       <ListItem
         key={p.id}
       >
         <Body>
           <Text style={{ color: p.gotten ? '#bbb' : '#000' }}>
             {p.name}
           </Text>
         </Body>
         <Right>
           <CheckBox
             checked={p.gotten}
            />
         </Right>
       </ListItem>
     );
   }
  )}
</List>
...

We now rely on a list of products inside our component's state, each product storing an id, a name, and gotten properties. When modifying this state, we will automatically be re-rendering the list.

Now, it's time to add some event handlers, so we can modify the state at the users' command or navigate to the AddProduct screen.

官术网_书友最值得收藏!

React Native Blueprints

Adding state to our screen