似乎无法使用 Expo 的 Font.loadAsync 加载自定义字体 [英] Can't seem to load custom fonts with Expo's Font.loadAsync

问题描述

我正在将 React Native 与 Expo 结合使用，除了自定义字体的这个问题外，一切都很顺利.我在 ./assets/fonts 中有我的字体 Lobster-Regular.ttf，我一直在尝试加载它，如官方文档中所示:

I'm using React Native with Expo, and it is all going well except for this one issue with custom fonts. I have my font Lobster-Regular.ttfin ./assets/fonts, and I have been trying to load it as seen in the official docs:

componentDidMount() {

    Font.loadAsync({

      'Lobster': require('./assets/fonts/Lobster-Regular.ttf'),
    });

  }

然后我将我的标题设置为:

I then style my header as such:

  headerText: {
    color: 'white',
    fontSize: 30,
    fontFamily: 'Lobster'
  }, 

我得到的只是

fontFamily 'Lobster' 不是系统字体，尚未加载通过 Font.loadAsync.

fontFamily 'Lobster' is not a system font and has not been loaded through Font.loadAsync.

• 如果您打算使用系统字体，请确保您输入的名称正确且受您的设备操作系统支持.

• If you intended to use a system font, make sure you typed the name correctly and that it is supported by your device operating system.

如果这是自定义字体，请务必使用 Font.loadAsync 加载它.

If this is a custom font, be sure to load it with Font.loadAsync.

我错过了什么吗?

推荐答案

是的.您错过了调用是 Font.loadAsync().这意味着它异步加载.如:这需要一段时间.在字体加载之前，您无法渲染 UI.您需要按照以下方式做一些事情:

Yes. You are missing that the call is Font.loadAsync(). This means that it loads asynchronously. As in: It takes a while. You can't render the UI until the font has loaded. You need to do something along these lines:

import { AppLoading, Font } from 'expo'

state = {
    fontsLoaded: false,
    ...
}

componentWillMount() {
    Font.loadAsync( {
            'Lobster': require('./assets/fonts/Lobster-Regular.ttf')
        }
    ).then( () => this.setState( { fontsLoaded: true } ) )
}

render() {
    if( !this.state.fontsLoaded ) {
        return <AppLoading/>
    }

    return (
        ...
    )
}

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