react native Scrollview在某些時候滾動無效

今天在使用Scrollview的時候滾動沒有效果，直接上程式碼：

   return(
<View style={{flex:1}}>
        <NavigatorHeader nav={this.props.nav} title="首頁"></NavigatorHeader>
        <HomeCategory nav={this.props
 
.nav} ClickCallback={this.props.ClickCallback}></HomeCategory>
     <ScrollView showsVerticalScrollIndicator={false}>
       <HomeSwiper nav={this.props.nav}/>
       <HomePictureTitleText textTittle1={'衛視熱播'} navigatior={this.props.nav} parentCode={'0909112305914'}/>
       <HomePictureTitleText textTittle1
 
={'熱門精選'} navigatior={this.props.nav} parentCode={'0909112423500'}/>
       <HomePictureTitleText textTittle1={'猜你喜歡'} navigatior={this.props.nav} parentCode={'0909112654380'}/>
       <HomePictureTitleText textTittle1={'為我推薦'} navigatior={this.props.nav} parentCode={'0909112712867'}/>
       
   </ScrollView
 
>
</View>
   );

後在scrollview中最後加入一個空的佈局就能滾動了：

在此做個記錄：

   return(
<View style={{flex:1}}>
        <NavigatorHeader nav={this.props.nav} title="首頁"></NavigatorHeader>
        <HomeCategory nav={this.props.nav} ClickCallback={this.props.ClickCallback}></HomeCategory>
     <ScrollView showsVerticalScrollIndicator={false}>
       <HomeSwiper nav={this.props.nav}/>
       <HomePictureTitleText textTittle1={'衛視熱播'} navigatior={this.props.nav} parentCode={'0909112305914'}/>
       <HomePictureTitleText textTittle1={'熱門精選'} navigatior={this.props.nav} parentCode={'0909112423500'}/>
       <HomePictureTitleText textTittle1={'猜你喜歡'} navigatior={this.props.nav} parentCode={'0909112654380'}/>
       <HomePictureTitleText textTittle1={'為我推薦'} navigatior={this.props.nav} parentCode={'0909112712867'}/>
         <View style={{height:Platform.OS == 'ios' ? 0:30,}}></View>
   </ScrollView>
</View>
   );

做個問題具體的原因我現在也不清楚，有知道的麻煩告知一下。謝謝