获取屏幕尺寸

//引用包var Dimensions = require('Dimensions');class DimensionsDemo extends Component {  render() {    return(      <View style = {dimentsionsStyle.dimensionStyle}>        {/*通过一个key*/}        <Text>当前屏幕宽度:{Dimensions.get('window').width}</Text>        <Text>当前屏幕高度:{Dimensions.get('window').height}</Text>        <Text>点钱屏幕分辨率:{Dimensions.get('window').scale}</Text>      </View>    );  }}const dimentsionsStyle = StyleSheet.create({  dimensionStyle: {    flex: 1,    justifyContent: 'center',    alignItems: 'center',  },});