How to remove a item/index from a FlatList in reac

问题:

I have a data which is rendered as view and came across a issue on how to remove that particular index which is swiped

I have used FlatList as follows

render() {
this.leftOpenValue =  Dimensions.get('window').width;
this.rightOpenValue = -Dimensions.get('window').width;

return (   

     <FlatList 
            data = {data}  
            keyExtractor = {data => data.id}                
            renderItem={ ({item}) => (

                <View style={styles.container}>
                    <SwipeView            
                        disableSwipeToRight = {false}
                        renderVisibleContent={() => 
                            <View>
                                <Text style={styles.text}> {item.title} </Text>     // This repeats 9 times (9 Index)              
                            </View>          
                        }
                        renderRightView={() => (
                            <View style={{flex:1, justifyContent: 'flex-end', alignItems: 'center', backgroundColor: 'red'}}>

                            </View>
                        )}

                        leftOpenValue = {this.leftOpenValue}
                        rightOpenValue = {this.rightOpenValue}
                        onSwipedLeft={() => alert("deleted")}
                        swipeDuration = {300}
                        swipeToOpenPercent = {40}
                        disableSwipeToRight = {true}
                    />
                </View>  

            )}
    />
);

I have used Swipeview to swipe (react-native-swipeview) and delete the index in flatlist

I have an issue on how to remove an item from flatList

回答1:

General pattern is to pass a uniquely identifiable id (key, index, etc...) to your delete handler and filter your data on values that don't equal that key. This returns a new array without that entry to store in state.

deleteItemById = id => {
  const filteredData = this.state.data.filter(item => item.id !== id);
  this.setState({ data: filteredData });
}

render() {
  ...

  return (   
    <FlatList 
      data={data} // Assuming this is `this.state.data`
      keyExtractor={({item}) => item.id}                
      renderItem={({item}) => (
        <View style={styles.container}>
          <SwipeView
            ...
            onSwipedLeft={() => this.deleteItemById(item.id)}
            ...
          />
        </View>  
      )}
    />
  );
}

Using a curried handler. This saves using an anonymous callback by setting the callback to be an event handler with the id enclosed in the function scope.

deleteItemById = id => () => {
  const filteredData = this.state.data.filter(item => item.id !== id);
  this.setState({ data: filteredData });
}

render() {
  ...

  return (   
    <FlatList 
      data={data} // Assuming this is `this.state.data`
      keyExtractor={({item}) => item.id}                
      renderItem={({item}) => (
        <View style={styles.container}>
          <SwipeView
            ...
            onSwipedLeft={this.deleteItemById(item.id)}
            ...
          />
        </View>  
      )}
    />
  );
}

回答2:

Pass an Id of the item to onSwipeLeft={this.deleteItem(item.id)} and update the data using setState.

state = {
    data: [{
      title: 'Hello world',
      id: 'hello'
    },{
      title: 'World says hello',
      id: 'say'
    }]
}

deleteItem = (id) => {

   this.setState({
    data: this.state.data.filter(item => item.id !== id)
   })

}