CameraRoll模块提供了访问本地相册的功能。在iOS上使用这个模块之前，你需要先链接RCTCameraRoll库，具体做法请参考链接原生库文档。

译注：本模块只提供了基本的访问图片的功能，并没有提供相册界面。对于多数开发者来说，可能react-native-image-picker的功能更为完整易用。

iOS 10的权限要求

从iOS10开始，访问相册需要用户授权。你需要在Info.plist中添加一条名为NSCameraUsageDescription的键，然后在其值中填写向用户请求权限的具体描述。编辑完成后这个键在Xcode中实际会显示为Privacy - Camera Usage Description。

故此，图片的读取使用react-native-image-picker 是后面常用的方法。

https://github.com/react-community/react-native-image-picker 这个是对应git 库。

里面包含了具体使用和安装方法。

Usage

var ImagePicker = require('react-native-image-picker');

// More info on all the options is below in the README...just some common use cases shown here

var options = {

  title: 'Select Avatar',

  customButtons: [

    {name: 'fb', title: 'Choose Photo from Facebook'},

  ],

  storageOptions: {

    skipBackup: true,

    path: 'images'

  }

};

ImagePicker.showImagePicker(options, (response) => {

  console.log('Response = ', response);

  if (response.didCancel) {

    console.log('User cancelled image picker');

  }

  else if (response.error) {

    console.log('ImagePicker Error: ', response.error);

  }

  else if (response.customButton) {

    console.log('User tapped custom button: ', response.customButton);

  }

  else {

    let source = { uri: response.uri };

    // You can also display the image using data:

    // let source = { uri: 'data:image/jpeg;base64,' + response.data };

    this.setState({

      avatarSource: source

    });

  }

});

Then later, if you want to display this image in your render() method:

Directly Launching the Camera or Image Library

To Launch the Camera or Image Library directly (skipping the alert dialog) you can do the following:

// Launch Camera:

ImagePicker.launchCamera(options, (response)  => {

  // Same code as in above section!

});

// Open Image Library:

ImagePicker.launchImageLibrary(options, (response)  => {

  // Same code as in above section!

});