CODEWITHSUNDEEP
dartflutterassets
Isaac
Isaac

Reputation: 1536

Check if a file exists before loading it

What I want to do is load an image in a Material Widget to use it in a ListTile, but this asset might not exist.

class MyImage extends StatelessWidget {
  final imagePath;

  MyIcon(String iconName) {
    try { // check if imagePath exists. Here is the problem
      imagePath = check('assets/$iconName.png/');
    } catch (e, s) { // if not
      imagePath = 'assets/$iconName.png/';
    }
  }

 @override
  Widget build(BuildContext context) {
    return Material(...here I will load the imagePath...);
 }
}

So, since I'm using a Stateless widget, I have to know beforehand if the image exists, otherwise I'll load a null right?

Upvotes: 78

Views: 89661

Answers (4)

Nae
Nae

Reputation: 15335

In order to see whether or not a file exists in internal local storage of the app use:

import 'dart:io' as io;
var syncPath = await path;

// for a file
await io.File(syncPath).exists();
io.File(syncPath).existsSync();

// for a directory
await io.Directory(syncPath).exists();
io.Directory(syncPath).existsSync();

Upvotes: 113

MaB
MaB

Reputation: 25

In order to see whether or not a file exists in local storage (as with image.network) now you can use :

Image.file(File("path/to/file"),
errorBuilder: (BuildContext context, Object exception, StackTrace? stackTrace) {return Text('file access error');

Upvotes: -3

Giuse Petroso
Giuse Petroso

Reputation: 647

For me simply worked this:

import 'dart:io';
File("path/to/file").exists()

or, for checking it synchronously

import 'dart:io';
File("path/to/file").existsSync()

Upvotes: 44

Richard Heap
Richard Heap

Reputation: 51702

Looks like you want to try to load an ImageProvider from a folder where the image may or may not exist and then, if it does not, load a fallback asset image (which you can be sure will exist as you'll put it in your root bundle).

Try this:

ImageProvider getImageProvider(File f) {
  return f.existsSync()
      ? FileImage(f)
      : const AssetImage('images/fallback.png');
}

Upvotes: 17

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