报错：setState(...): Cannot update during an existing state transition

Question

代码如下：

var Video=require('react-native-video').default;

_onProgress(data){

   if(!this.state.videoLoaded){
       this.setState({
           videoLoaded:true
       })
   }
   console.log(data)

   console.log('progress')

}

render(){

return(

<View style={styles.container}>

<Video ref='videoPlayer' source={{uri:'http://video.iblack7.com/video_hcwijdwneqantgb4yqgx.mp4'}} onProgress={this._onProgress} />

</View>)

}

以上代码运行的时候报错：setState(...): Cannot update during an existing state transition (such as within `render` or another component's constructor). Render methods should be a pure function of props and state; constructor side-effects are an anti-pattern, but can be moved to `componentWillMount`

具体的意思我觉得应该是reader里面执行的this._onProgress方法里有一个setState不能够执行到。但我不知道怎么改，有哪位大神或老师帮忙看看吗？跪谢！！