//  在android/app/src/mian/AndroidManifest.xml
android:windowSoftInputMode="stateAlwaysHidden|adjustPan"`將這個替換成`android:windowSoftInputMode="adjustResize"

<View style={{height: this.state.scrollViewHeight}}>

<ScrollView 
    ref={(r)=>this.scrollRef = r}                
    style={{backgroundColor:"#fff",flex:1}}
 >
       <RichEditor
        ref={(r) => this.richtext = r}                     
        placeholder="寫下來，思考才會越來越清晰"                     
        editorInitializedCallback={() => this.onEditorInitialized()}
        onChange = {e=>this.state.htmlText=e}                    
        initialHeight={this.state.scrollViewHeight} 
        onCursorPosition={(currentHeight)=>this.handleScroll(currentHeight)}
        onFocus={(a)=>this._getFoucs(a)}  //這里我暫時，沒法獲得“焦點位置的當前高度”                    
    />
< /ScrollView> 
</view>

handleScroll(currentHeight){
   this.scrollRef.scrollTo({y: currentHeight - 30, animated: true});
}

Manifest merger failed : uses-sdk:minSdkVersion 16 cannot be smaller than version 21 declared in library [:react-native-image-picker]