React-native：将场景绑定到 NavigationBar

Question

我正在制作这个 Ask/Answer App，但遇到了这个障碍：

我想从导航栏触发场景中的一个功能。与登录应用类似，我在 NavigationBar 中有一个按钮来提交答案：

RightButton(route, navigator, index, navState) {
    if (route.name=='TextInputView'){
     return <TouchableHighlight
             underlayColor="transparent"
             style={{ marginRight:13,  marginTop:0}}
             onPress={() => this.refs.TextInputView.submitSolution()}>
        <Text style={ styles.leftNavButtonText }>Done</Text>
      </TouchableHighlight>
    }

renderscene(route,navigator) 看起来像这样：

if (route.name == 'TextInputView'){
  return <TextInputView ref="TextInputView" navigator={navigator} {...route.passProps}/>
}

当然在“TextInputView”组件中我有一个“submitSolution”功能...

问题是如果我在场景中并按“完成” - 我总是得到： "未定义不是对象（评估'_this2.refs.TextInputView'）

一如既往：感谢您的帮助

Answer 1

好吧，您可以通过将与提交相关的所有内容保留在场景本身中来做到这一点。

怎么做？

您可以通过在导航栏中按需注入一个按钮来实现。

这是我为我正在从事的项目创建的解决方案： https://rnplay.org/apps/dS31zw

这个想法是为导航栏路线提供一个具有标签和功能的对象（以及任何你喜欢的东西......例如图标。）

作为奖励，您也可以注入标题！

注意：这个技巧依赖于在 NavigationBarRouteMapper 工作之前调用 componentWillMount()。如果以后这种变化，肯定会打破它。但它现在完美无缺！

'use strict';

import React, {Component} from 'react';
import ReactNative from 'react-native';

const {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  Navigator,
  Alert,
  TouchableHighlight
} = ReactNative;

class Home extends Component {

  //This trick depends on that componentWillMount fires before the navbar is created
  componentWillMount() {
        this.props.route.navbarTitle = "Home";

        this.props.route.rightNavButton = {
            text: "Button",
            onPress: this._doSomething.bind(this)
        };
    }

  _doSomething() {
    Alert.alert(
      'Awesome, eh?',
      null,
      [
        {text: 'Indeed'},
      ]
    )
  }

  render() {
    return (
      <View style={styles.container}>
            <Text>You are home</Text>
        </View>
    );
  }
}

class AppContainer extends Component {

    renderScene(route, navigator) {
        switch(route.name) {
            case "Home":
      //You must pass route as a prop for this trick to work properly
            return <Home route={route} navigator={navigator} {...route.passProps}  />
            default:
            return (
        <Text route={route}
        style={styles.container}>
            Your route name is probably incorrect {JSON.stringify(route)}
            </Text>
      );
        }
    }

  render() {
    return (
      <Navigator
        navigationBar={
          <Navigator.NavigationBar
            style={ styles.navbar }
            routeMapper={ NavigationBarRouteMapper } />
        }

        initialRoute={{ name: 'Home' }}
        renderScene={ this.renderScene }

      />
    );
  }
}

//Nothing fancy here, except for checking for injected buttons.
var NavigationBarRouteMapper = {
  LeftButton(route, navigator, index, navState) {
    if(route.leftNavButton) {
      return (
        <TouchableHighlight
        style={styles.leftNavButton}
        underlayColor="transparent"
        onPress={route.leftNavButton.onPress}>
          <Text style={styles.navbarButtonText}>{route.leftNavButton.text}</Text>
        </TouchableHighlight>
      );
    }
    else if(route.enableBackButton) {
      return (
        <TouchableHighlight
        style={styles.leftNavButton}
        underlayColor="transparent"
        onPress={() => navigator.pop() }>
          <Text style={styles.navbarButtonText}>Back</Text>
        </TouchableHighlight>
      );
    }
  },
  RightButton(route, navigator, index, navState) {
    if(route.rightNavButton) {
      return (
        <TouchableHighlight
        style={styles.rightNavButton}
        underlayColor="transparent"
        onPress={route.rightNavButton.onPress}>
          <Text style={styles.navbarButtonText}>{route.rightNavButton.text}</Text>
        </TouchableHighlight>
      );
    }
  },
  Title(route, navigator, index, navState) {
    return (<Text style={styles.navbarTitle}>{route.navbarTitle || route.name}</Text>);
  }
};

var styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
    marginTop: 66
  },
  navbar: {
    backgroundColor: '#ffffff',
  },
  navbarTitle: {
    marginVertical: 10,
    fontSize: 17
  },
  leftNavButton: {
    marginVertical: 10,
    paddingLeft: 8,
 },
  rightNavButton: {
    marginVertical: 10,
    paddingRight: 8,
  },
  navbarButtonText: {
    fontSize: 17,
    color: "#007AFF"
  }
});

AppRegistry.registerComponent('AppContainer', () => AppContainer);