以编程方式触发新闻

时间:2018-10-31 08:44:36

标签: javascript react-native react-component

我有以下内容

class LanguageScreen extends Component {

    _onPressButton() {

    }

    render() {
        var enButton = <RoundButton 
            buttonStyle={'black-bordered'}
            text={'EN'}
            locale={'en'}
            selected={true}
            style={styles.roundButtonStyle}
            onPress={this._onPressButton}
        />
        var arButton = <RoundButton
            buttonStyle={'golden-gradient'}
            text={'ع'}
            locale={'ar'}
            selected={false}
            style={styles.roundButtonStyle}
            onPress={this._onPressButton}
        />
        return(
            <View style={styles.rootViewStyle}>
                <View style={styles.buttonContainerRootViewStyle}>
                    <View style={styles.buttonContainerViewStyle}>
                        {enButton}
                        {arButton}
                    </View>
                </View>
                <View style={styles.submitButtonContainerViewStyle}>
                    <Button style={styles.submitButtonStyle}/>
                </View>
            </View>
        );
    }
}

当用户按下enButton时,我想更改arButton的样式,反之亦然,为您提供图片,屏幕截图下方的PFA。

enter image description here

基本上,我想一次突出显示一个按钮,可以说用户单击EN,我想突出显示所选元素并从其他元素中删除突出显示。

这是我的RoundButton组件类

class RoundButton extends Component {

    constructor(props) {
        super(props);
        this.state = { isSelected: true === props.selected };
    }

    onClickListen = () => {
        this.setState({
            isSelected: !this.state.isSelected 
        });
        this.forceUpdate();
    }

    render() {
        if (this.state.isSelected) {
            return this.goldenGradient(this.props);
        } else {
            return this.blackBordered(this.props)
        }   
    }

    goldenGradient(props) {
        return(
            <TouchableOpacity
                style={styles.buttonStyle}
                onPress={this.props.onPress}
                onPressOut={this.onClickListen}
            >
                <LinearGradient
                    colors={['#E9E2B0', '#977743']}
                    start={{x: 1.0, y: 0.0}}
                    end={{x: 0.0, y: 1.0}}
                    style={styles.linearGradient}
                >
                    <Text style={this.props.locale == 'ar' ? styles.goldenGradientTextStyleAr : styles.goldenGradientTextStyle}>
                        {props.text}
                    </Text>
                </LinearGradient>
            </TouchableOpacity>
        );
    }

    blackBordered(props) {
        return(
            <TouchableOpacity
                style={
                    styles.buttonStyle,
                    styles.blackBorderedStyle
                }
                onPress={this.props.onPress}
                onPressOut={this.onClickListen}
            >
                <Text style={this.props.locale == 'ar' ? styles.blackBorderedTextStyleAr : styles.blackBorderedTextStyle}>
                    {props.text}
                </Text>
            </TouchableOpacity>
        );
    }
}

我正在寻找的解决方案是,如果用户单击EN按钮,那么我希望其他按钮也触发按下,这将导致状态更改并切换突出显示状态。似乎没有解决方案。我该怎么办?

2 个答案:

答案 0 :(得分:1)

对此的最佳解决方案是让父组件管理按钮高亮显示。因此,您必须将当前选定的按钮置于父组件的状态,然后将布尔属性传递给该按钮,以指示该按钮是否被选中。如我所见,您已经通过了一个“选定的”道具,该道具应该在父组件中处理,而不是在按钮的组件中处理。

如果按照您说的做,您将中断自上而下的数据流,其反应基于

更新

父亲组成部分

添加构造函数:

constructor(props) {
  super(props);

  this.state = {
    selectedButton: 'en'
  };

  this._onPressButton = this._onPressButton.bind(this); 
}

按下按钮:

_onPressButton(button) {
  this.setState({
    selectedButton: button
  });
}

按钮初始化:

const arButton = <RoundButton
        buttonStyle={'golden-gradient'}
        text={'ع'}
        locale={'ar'}
        selected={this.checkButtonSelect('ar')}
        style={styles.roundButtonStyle}
        onPress={this._onPressButton}/>

const enButton = <RoundButton 
        buttonStyle={'black-bordered'}
        text={'EN'}
        locale={'en'}
        selected={this.checkButtonSelect('en')}
        style={styles.roundButtonStyle}
        onPress={this._onPressButton}

检查是否选择了按钮

checkButtonSelect(button) {
  return this.state.selectedButton === button;
}

按钮组件

很自我解释

class RoundButton extends Component {

constructor(props) {
    super(props);
    this.state = { isSelected: true === props.selected };
}

onClickListen = () => {
    this.props.onPress(this.props.locale);

    /*
    * You dont need this, the component is already updated on setState()
    * call
    */
    //this.forceUpdate();
}

render() {
    if (this.state.isSelected) {
        return this.goldenGradient(this.props);
    } else {
        return this.blackBordered(this.props)
    }   
}

goldenGradient(props) {
    return(
        <TouchableOpacity
            style={styles.buttonStyle}
            onPress={this.onClickListen}
        >
            <LinearGradient
                colors={['#E9E2B0', '#977743']}
                start={{x: 1.0, y: 0.0}}
                end={{x: 0.0, y: 1.0}}
                style={styles.linearGradient}
            >
                <Text style={this.props.locale == 'ar' ? styles.goldenGradientTextStyleAr : styles.goldenGradientTextStyle}>
                    {props.text}
                </Text>
            </LinearGradient>
        </TouchableOpacity>
    );
}

blackBordered(props) {
    return(
        <TouchableOpacity
            style={
                styles.buttonStyle,
                styles.blackBorderedStyle
            }
            onPress={this.props.onPress}
            onPressOut={this.onClickListen}
        >
            <Text style={this.props.locale == 'ar' ? styles.blackBorderedTextStyleAr : styles.blackBorderedTextStyle}>
                {props.text}
            </Text>
        </TouchableOpacity>
    );
}
}

答案 1 :(得分:1)

您是否考虑过更改呈现按钮的父组件中的状态?为什么不跟踪LanguageScreen中按下了哪个按钮,然后将此信息传递给按钮。

    _onPressButton (selectedLocale) {
      this.setState({ selectedLocale })
    }

    var enButton = <RoundButton 
        onPress={this._onPressButton}
        isSelected={this.state.selectedLocale === 'en'}
        ...youStaff
    />
    var arButton = <RoundButton
        onPress={this._onPressButton}
        isSelected={this.state.selectedLocale === 'ar'}
        ...yourStaff
    />

在您的RoundButton中:

onClickListen = () => {
    this.props.onPress(this.props.locale)
}

render() {
    if (this.props.isSelected) {
        return this.goldenGradient(this.props);
    } else {
        return this.blackBordered(this.props)
    }   
}