React Native: Why is image stretching vertically to fill container and how to prevent it?

问题

In my React Native app, I have a red box of height 300 that I want to center vertically, and an image that I want to sit inside and at the top of this red box. Here is my code so far:

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

export default class Login extends Component {
  render() {
    return (
      <View style={{
          flex: 1,
          justifyContent: "center",
          alignItems: "center"
        }}>
          <View
            style={{
              borderWidth: 3,
              borderColor: 'red',
              width: "100%",
              height: 300
            }}
          >
            <Image
              source={require('../../images/swoord-top.png')}
              style={{
                width: "100%",
                height: "100%",
                resizeMode: "contain",
                borderWidth: 3
              }}
              >
            </Image>
          </View>
      </View>
    );
  }
}

Here's what this looks like:

The red box is the outer box I mentioned, and the black box is just the border of the Image. The problem is that this black box (ie the Image) expands to fill the red box vertically, and the image is vertically centered inside this black box, so it's vertically centered inside the red box, as opposed to at the flex-start position that I want it at. I've tried adding justifyContent: flex-start and flexShrink: 1 to the Image and neither has made a difference.

Does anyone know how I can approach this?

NOTE:

If I remove the height: 100% on the Image, I get this:

UPDATE:

To clarify, this is what I'd like it to look like. I've removed the black border here. I moved it up to where I want it by adding top: -95, but this won't work in general because the value would be different for different devices:

回答1:

try doing like this

 <Image
              source={require('../../images/swoord-top.png')}
              style={{
                width: "100%",
                borderWidth: 3
              }}
              resizeMode={"contain"}
              />

回答2:

There is a difference between Image (the view) and the content of that image. On your screenshot, the image view has the black border and its content is sitting inside of it. Because they have different aspect ratios, there is going to be either a blank space or cut-off on the content. You can't adjust position of the content as it's not laid out on flex basis. Image view is just a window that then renders image content. There is no property to tell Image where to align that content

Your problem comes from the fact that screen width differs, and aspect ratio of your container also differs (variable width but constant 300 height). What you need to do is

measure container width
determine proper aspect ratio for the image based on image resource width and height
set your image width to 100% and its height according to received aspect ratio

here, my image dimensions are 1005 * 219:

const Test = () => {
  const [width, setWidth] = useState(0);
  return (
    <View>
      <View
        onLayout={e => setWidth(e.nativeEvent.layout.width)}
        style={{ width: '100%', height: 300, borderWidth: 1 }}>
        <Image
          style={{
            width: '100%',
            height: (width / 1005) * 219,
            borderWidth: 1,
            borderColor: 'red',
          }}
          source={require('...')}
        />
      </View>
    </View>
  );
};

来源：https://stackoverflow.com/questions/60946102/react-native-why-is-image-stretching-vertically-to-fill-container-and-how-to-pr

标签

reactjs

react-native

react-native-image