基本上，如果你想设置大小并改变它，那么在布局上设置它为state，如下所示:

import React, { Component } from 'react';
import { AppRegistry, StyleSheet, View } from 'react-native';

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: 'yellow',
  },
  View1: {
    flex: 2,
    margin: 10,
    backgroundColor: 'red',
    elevation: 1,
  },
  View2: {
    position: 'absolute',
    backgroundColor: 'orange',
    zIndex: 3,
    elevation: 3,
  },
  View3: {
    flex: 3,
    backgroundColor: 'green',
    elevation: 2,
  },
  Text: {
    fontSize: 25,
    margin: 20,
    color: 'white',
  },
});

class Example extends Component {

  constructor(props) {
    super(props);

    this.state = {
      view2LayoutProps: {
        left: 0,
        top: 0,
        width: 50,
        height: 50,
      }
    };
  }

  onLayout(event) {
    const {x, y, height, width} = event.nativeEvent.layout;
    const newHeight = this.state.view2LayoutProps.height + 1;
    const newLayout = {
        height: newHeight ,
        width: width,
        left: x,
        top: y,
      };

    this.setState({ view2LayoutProps: newLayout });
  }

  render() {
    return (
      <View style={styles.container}>
        <View style={styles.View1}>
          <Text>{this.state.view2LayoutProps.height}</Text>
        </View>
        <View onLayout={(event) => this.onLayout(event)} 
              style={[styles.View2, this.state.view2LayoutProps]} />
        <View style={styles.View3} />
      </View>
    );
  }

}


AppRegistry.registerComponent(Example);

你可以创建更多的变化，它应该如何修改，通过使用这个在另一个组件有另一个视图包装和创建一个onResponderRelease回调，它可以传递触摸事件位置到状态，然后可以传递给子组件作为属性，这可以覆盖onLayout更新状态，通过放置{[样式。View2 this.state。view2LayoutProps this.props。}等等。

从React Native 0.4.2开始，视图组件就有了onLayout道具。传入一个接受事件对象的函数。事件的nativeEvent包含了视图的布局。

<View onLayout={(event) => {
  var {x, y, width, height} = event.nativeEvent.layout;
}} />

每当视图调整大小时，onLayout处理程序也将被调用。

主要的警告是onLayout处理程序是在组件挂载后的一帧首次调用的，因此您可能希望在计算布局之前隐藏UI。

也许你可以用measure:

measureProgressBar() {
    this.refs.welcome.measure(this.logProgressBarLayout);
},

logProgressBarLayout(ox, oy, width, height, px, py) {
  console.log("ox: " + ox);
  console.log("oy: " + oy);
  console.log("width: " + width);
  console.log("height: " + height);
  console.log("px: " + px);
  console.log("py: " + py);
}

基本上，如果你想设置大小并改变它，那么在布局上设置它为state，如下所示:

import React, { Component } from 'react';
import { AppRegistry, StyleSheet, View } from 'react-native';

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: 'yellow',
  },
  View1: {
    flex: 2,
    margin: 10,
    backgroundColor: 'red',
    elevation: 1,
  },
  View2: {
    position: 'absolute',
    backgroundColor: 'orange',
    zIndex: 3,
    elevation: 3,
  },
  View3: {
    flex: 3,
    backgroundColor: 'green',
    elevation: 2,
  },
  Text: {
    fontSize: 25,
    margin: 20,
    color: 'white',
  },
});

class Example extends Component {

  constructor(props) {
    super(props);

    this.state = {
      view2LayoutProps: {
        left: 0,
        top: 0,
        width: 50,
        height: 50,
      }
    };
  }

  onLayout(event) {
    const {x, y, height, width} = event.nativeEvent.layout;
    const newHeight = this.state.view2LayoutProps.height + 1;
    const newLayout = {
        height: newHeight ,
        width: width,
        left: x,
        top: y,
      };

    this.setState({ view2LayoutProps: newLayout });
  }

  render() {
    return (
      <View style={styles.container}>
        <View style={styles.View1}>
          <Text>{this.state.view2LayoutProps.height}</Text>
        </View>
        <View onLayout={(event) => this.onLayout(event)} 
              style={[styles.View2, this.state.view2LayoutProps]} />
        <View style={styles.View3} />
      </View>
    );
  }

}


AppRegistry.registerComponent(Example);

你可以创建更多的变化，它应该如何修改，通过使用这个在另一个组件有另一个视图包装和创建一个onResponderRelease回调，它可以传递触摸事件位置到状态，然后可以传递给子组件作为属性，这可以覆盖onLayout更新状态，通过放置{[样式。View2 this.state。view2LayoutProps this.props。}等等。

我创建了这个简单的组件

import React, {Dispatch, SetStateAction} from 'react';
import {View, ViewProps} from 'react-native';

interface GetDimensionsProps {
  children: React.ReactNode | React.ReactNode[];
  onDimensions: Dispatch<SetStateAction<{height: number; width: number}>>;
  viewProps?: ViewProps;
}

export const GetDimensions: React.FC<GetDimensionsProps> = ({
  children,
  onDimensions,
  ...viewProps
}: GetDimensionsProps) => {
  return (
    <View
      onLayout={event =>
        onDimensions({
          width: Math.round(event.nativeEvent.layout.width),
          height: Math.round(event.nativeEvent.layout.height),
        })
      }
      {...viewProps}>
      {children}
    </View>
  );
};

// ────────────────────────────────────────────────────────────────────────────────
// usage

// const [dimensions, setDimensions] = useState<{
//   height: number;
//   width: number;
// }>({width: 0, height: 0});
//
// <GetDimensions onDimensions={setDimensions}>
//  {children}
// </GetDimensions>

这是唯一对我有效的方法:

import React, { Component } from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  Image
} from 'react-native';

export default class Comp extends Component {

  find_dimesions(layout){
    const {x, y, width, height} = layout;
    console.warn(x);
    console.warn(y);
    console.warn(width);
    console.warn(height);
  }
  render() {
    return (
      <View onLayout={(event) => { this.find_dimesions(event.nativeEvent.layout) }} style={styles.container}>
        <Text style={styles.welcome}>
          Welcome to React Native!
        </Text>
        <Text style={styles.instructions}>
          To get started, edit index.android.js
        </Text>
        <Text style={styles.instructions}>
          Double tap R on your keyboard to reload,{'\n'}
          Shake or press menu button for dev menu
        </Text>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});

AppRegistry.registerComponent('Comp', () => Comp);