Convert Base64 String to an Image File

 function dataURLtoFile(dataurl, filename) {         var arr = dataurl.split(','),            mime = arr[0].match(/:(.*?);/)[1],            bstr = atob(arr[1]),             n = bstr.length,             u8arr = new Uint8Array(n);                    while(n--){            u8arr[n] = bstr.charCodeAt(n);        }                return new File([u8arr], filename, {type:mime});    }        //Usage example:    var file = dataURLtoFile('data:text/plain;base64,aGVsbG8gd29ybGQ=','hello.txt');    console.log(file);

How to convert BASE64 string into Image with Flutter?

You can convert a Uint8List to a Flutter Image widget using the Image.memory constructor. (Use the Uint8List.fromList constructor to convert a List to Uint8List if necessary.) You can use BASE64.encode to go the other way.

Here's some sample code.

import 'dart:async';
import 'dart:convert';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

void main() {
  runApp(new MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      theme: new ThemeData.dark(),
      home: new MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  State createState() => new MyHomePageState();
}

class MyHomePageState extends State<MyHomePage> {
  String _base64;

  @override
  void initState() {
    super.initState();
    (() async {
      http.Response response = await http.get(
        'https://flutter.io/images/flutter-mark-square-100.png',
      );
      if (mounted) {
        setState(() {
          _base64 = BASE64.encode(response.bodyBytes);
        });
      }
    })();
  }

  @override
  Widget build(BuildContext context) {
    if (_base64 == null)
      return new Container();
    Uint8List bytes = BASE64.decode(_base64);
    return new Scaffold(
      appBar: new AppBar(title: new Text('Example App')),
      body: new ListTile(
        leading: new Image.memory(bytes),
        title: new Text(_base64),
      ),
    );
  }
}

However, it's generally a bad idea to store large blobs of binary data in your database. It's not playing to the strengths of Firebase realtime database and you will end up wasting bandwidth transmitting data you don't need as well as unnecessary encoding and decoding. You should use the firebase_storage plugin instead, storing the path or download URL of the image in the database.

Convert base64 string to Image in Java

I'm worried about that you need to decode only the base64 string to get the image bytes, so in your

"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAVI..."

string, you must get the data after data:image\/png;base64,, so you get only the image bytes and then decode them:

String imageDataBytes = completeImageData.substring(completeImageData.indexOf(",")+1);

InputStream stream = new ByteArrayInputStream(Base64.decode(imageDataBytes.getBytes(), Base64.DEFAULT));

This is a code so you understand how it works, but if you receive a JSON object it should be done the correct way:

• Converting the JSON string to a JSON object.
• Extract the String under data key.
• Make sure that starts with image/png so you know is a png image.
• Make sure that contains base64 string, so you know that data must be decoded.
• Decode the data after base64 string to get the image.

Convert base64 string to PNG image in android

Use this

    byte[] decodedString = Base64.decode(imageString, Base64.DEFAULT);
    // Bitmap Image
    Bitmap bitmap = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);

    String filename = "MyImage.png";
    File file= Environment.getExternalStorageDirectory();
    File dest = new File(file, filename);

    try {
         FileOutputStream out = new FileOutputStream(dest);
         bitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
         out.flush();
         out.close();
    } catch (Exception e) {
         e.printStackTrace();
    }

Required Permission in AndroidManifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

converting a base 64 string to an image and saving it

Here is an example, you can modify the method to accept a string parameter. Then just save the image object with image.Save(...).

public Image LoadImage()
{
    //data:image/gif;base64,
    //this image is a single pixel (black)
    byte[] bytes = Convert.FromBase64String("R0lGODlhAQABAIAAAAAAAAAAACH5BAAAAAAALAAAAAABAAEAAAICTAEAOw==");

    Image image;
    using (MemoryStream ms = new MemoryStream(bytes))
    {
        image = Image.FromStream(ms);
    }

    return image;
}

It is possible to get an exception A generic error occurred in GDI+. when the bytes represent a bitmap. If this is happening save the image before disposing the memory stream (while still inside the using statement).

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