React Native CameraRoll.getPhotos API doesn't render the results

Question

Hi I have the following class where I am trying to get the photos from camera roll and display it.

class CameraRollProject extends Component {
  constructor(props) {
    super(props);
    this.state = {
     images: []
    };
  }

  componentWillMount() {
    const fetchParams = {
      first: 25,
    };
    CameraRoll.getPhotos(fetchParams, this.storeImages, this.logImageError);
  }

  storeImages(data) {
    const assets = data.edges;
    const images = assets.map((asset) => asset.node.image);
    this.state.images =  images;
  }

  logImageError(err) {
    console.log(err);
  }

  render() {
      return (
        <ScrollView style={styles.container}>
          <View style={styles.imageGrid}>
            { this.state.images.map((image) => <Image style={styles.image} source={{ uri: image.uri }} />) }
          </View>          
        </ScrollView>
      );
  }
};

export default CameraRollProject;

The issue is my render function is getting called before my CameraRoll.getPhotos promise get resolved. So I don't get any photos.

To solve this issue I changed my program into following

render() {
      return CameraRoll.getPhotos(fetchParams, this.storeImages, this.logImageError)
        .then(() => {
          return (
            <ScrollView style={styles.container}>
              <View style={styles.imageGrid}>
                { this.state.images.map((image) => <Image style={styles.image} source={{ uri: image.uri }} />) }
              </View>          
            </ScrollView>
          );
        });
  }

However this give me the following error

What can I do in above situation? How can I make sure the render only works after the CameraRoll.getPhotos get resolved.

Answer 1

So I resolved this issue. The main reason for my problem was I was not using CameraRoll.getPhotos properly as a Promise. I was passing incorrect parameter inside the function. To solve this I got rid of the following functions

 storeImages(data) {
    const assets = data.edges;
    const images = assets.map((asset) => asset.node.image);
    this.state.images =  images;
  }

  logImageError(err) {
    console.log(err);
  }

And make my CameraRoll.getPhotos like the following

CameraRoll.getPhotos({first: 5}).then(
  (data) =>{
    const assets = data.edges
    const images = assets.map((asset) => asset.node.image);
        this.setState({
          isCameraLoaded: true,
          images: images
        })
  },
  (error) => {
     console.warn(error);
  }
);

Here is my complete code to get pictures from CameraRoll in react-native just in case anyone interested

class CameraRollProject extends Component {
  constructor(props) {
    super(props);
    this.state = {
     images: [],
     isCameraLoaded: false
    };
  }

  componentWillMount() {
    CameraRoll.getPhotos({first: 5}).then(
      (data) =>{
        const assets = data.edges;
        const images = assets.map((asset) => asset.node.image);
        this.setState({
          isCameraLoaded: true,
          images: images
        })
      },
      (error) => {
        console.warn(error);
      }
    );
  }

  render() {
      if (!this.state.isCameraLoaded) {
        return (
          <View>
            <Text>Loading ...</Text>
          </View>
          );
      }
      return (
        <ScrollView style={styles.container}>
          <View style={styles.imageGrid}>
            { this.state.images.map((image) => <Image style={styles.image} source={{ uri: image.uri }} />) }
          </View>          
        </ScrollView>
      );
  }
};

export default CameraRollProject;

Answer 2

I think you should use react-native-image-picker

You have many parameters to retrieve a picture as you wish

  selectPhotoTapped() {
    const options = {
      title: 'Choose a picture',
      cancelButtonTitle: 'Back',
      takePhotoButtonTitle: 'Take a picture...',
      chooseFromLibraryButtonTitle: 'Choose from my pictures..',
      quality: 1,
      maxWidth: 300,
      maxHeight: 300,
      allowsEditing: true,
      mediaType: 'photo',
      storageOptions: {
        skipBackup: true
      }
    }

it is much easier to handle than CameraRollProject, and the documentation is very well explained. for what you would do it suits perfectly. (It works on iOS and Android)

Answer 3

One way to do this would be to use a ListView rather than a Scrollview because you can utilize a datasource . Here is a sample of how you could do this:

constructor(props) {
  super(props);

  const ds = new ListView.DataSource({ rowHasChanged: (r1, r2) => r1 !== r2 });
  this.state = { dataSource: ds.cloneWithRows([]) };

  this.loadPhotos();
}

loadPhotos() {
  const fetchParams = {
    first: 25,
  };

  CameraRoll.getPhotos(fetchParams).then((data) => {
    this.state.dataSource.cloneWithRows(data.edges);
  }).catch((e) => {
    console.log(e);
  });
}

This way, you render an empty list (and a loading state for good UX) and then once the fetch has completed you set the data in the ListView .

If you want to stick with the ScrollView and the mapped images, you would also need some sort of loading state until the photos load. Hope this helps.