TypeError: undefined is not an object (evaluating 'routes[index].params.theme')

Question

老师这个怎么解决

Answer 1

CrazyCodeBoy 2018-07-09 09:57:49

确认下react-navigation的版本如果是2.0以上版本参考如下代码：

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

import {createDrawerNavigator, createStackNavigator,SafeAreaView,DrawerItems} from 'react-navigation'; import {createBottomTabNavigator, BottomTabBar} from 'react-navigation-tabs';   class TabBarComponent extends React.Component {     constructor(props) {         super(props);         this.theme = {             tintColor: props.activeTintColor,             updateTime: new Date().getTime()         }     }       render() {         const {routes, index} = this.props.navigation.state;         const {theme} = routes[index].params;         if (theme && theme.updateTime > this.theme.updateTime) {             this.theme = theme;         }         /**          * custom tabBarComponent          * https://github.com/react-navigation/react-navigation/issues/4297          */         return (             <BottomTabBar                 {...this.props}                 activeTintColor={this.theme.tintColor || this.props.activeTintColor}             />         );     }   }   export const AppTabNavigator = createBottomTabNavigator({     Page1: {     ...

Answer 2

r4ggjlx 2018-07-07 23:59:03

routes[index].params ===undefined?

• 提问者 liuxiaozhu #1

  想知道根本原因，routes[index] 跟 theme 到底是哪里来的？课程里根本没有提到。

• CrazyCodeBoy 回复 提问者 liuxiaozhu #2

  theme 在Page1中有介绍：
  
  <Button
                  title="改变主题色"
                  onPress={() => {
                      navigation.setParams({theme:{
                          tintColor:'orange',
                          updateTime:new Date().getTime()
                      }})
                  }}
              />

• 提问者 liuxiaozhu 回复 CrazyCodeBoy #3

  第一次加载的时候，确实是 undefined。我想知道第一次加载时，在哪里配置传入这个 params ？