React-Native ViewPager goToPage 不工作

Question

import ViewPager from 'react-native-viewpager';
constructor(props){
        super(props);

        this._renderPage = this._renderPage.bind(this);
        this._renderRowSablon = this._renderRowSablon.bind(this);
        this.PageChange = this.PageChange.bind(this);
        this.count = 0;
        this.state = {
              count: 0,
              info : this.props.values,
              page: 0,
              pages:pages,
        }
 }
 PageChange(x){
        switch(x){
              case 'next':
                    if( this.state.count< (this.state.info.sayfa - 1) ){
                          this.viewpager.goToPage(this.state.count + 1);
                          this.setState({count: this.state.count+ 1});
                    }
              break;
        }
  }
render(){
            <View style={{flex:1}}>
               <ViewPager
                   ref={(viewpager) => {this.viewpager = viewpager}}
                   dataSource={this.state.dataSource}
                   renderPage={this._renderPage}
                   onChangePage={this._pageChange}
                    isLoop={false}
                   renderPageIndicator={false}
                   locked={true}
                   autoPlay={false}/>
             </View>
             <View style={{flex:1}}>
                 <TouchableHighlight onPress={() => { this.PageChange('next'); }}>
                 <Text>Next</Text>
                  </TouchableHighlight>
             </View>
}

当 setState 函数被清除时，页面改变正在发生。添加 setState 函数时（如上），setState 有效，但页面更改 (gotoPage) 无效。不显示错误/警告到底是什么问题？

Answer 1

您似乎超出了范围。当使用箭头函数时，'this' 的范围变成了词法。

尝试更改<TouchableHighlight onPress={() => { this.PageChange('next'); }}>

到<TouchableHighlight onPress={this.PageChange('next')}>

看到这个问题： React-Native: Cannot access state values or any methods declared from renderRow