The below will allow you to send a file (specifically an image in this example) using UIActivityViewController on iOS and as a share intent on Android.
FileProvider overview (Android)
Update pubspec.yaml to reference your image if local (image.jpg in this example) and to use the path_provider plugin in order to access the file system. https://pub.dartlang.org/packages/path_provider
main.dart
import 'dart:io';
import 'dart:typed_data';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:path_provider/path_provider.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Share Demo',
theme: new ThemeData(
primarySwatch: Colors.blue,
),
home: new MyHomePage(title: 'Share Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => new _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
@override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text(widget.title),
),
body: new Center(
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
],
),
),
floatingActionButton: new FloatingActionButton(
onPressed: _shareImage,
tooltip: 'Share',
child: new Icon(Icons.share),
),
);
}
_shareImage() async {
try {
final ByteData bytes = await rootBundle.load('assets/image.jpg');
final Uint8List list = bytes.buffer.asUint8List();
final tempDir = await getTemporaryDirectory();
final file = await new File('${tempDir.path}/image.jpg').create();
file.writeAsBytesSync(list);
final channel = const MethodChannel('channel:me.albie.share/share');
channel.invokeMethod('shareFile', 'image.jpg');
} catch (e) {
print('Share error: $e');
}
}
}
AppDelegate.m
#include "AppDelegate.h"
#include "GeneratedPluginRegistrant.h"
@implementation AppDelegate
static NSString *const SHARE_CHANNEL = @"channel:me.albie.share/share";
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[GeneratedPluginRegistrant registerWithRegistry:self];
FlutterViewController* controller = (FlutterViewController*)self.window.rootViewController;
FlutterMethodChannel *shareChannel =
[FlutterMethodChannel methodChannelWithName:SHARE_CHANNEL
binaryMessenger:controller];
[shareChannel setMethodCallHandler:^(FlutterMethodCall *call, FlutterResult result) {
if ([@"shareFile" isEqualToString:call.method]) {
[self shareFile:call.arguments
withController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
}];
return [super application:application didFinishLaunchingWithOptions:launchOptions];
}
- (void)shareFile:(id)sharedItems withController:(UIViewController *)controller {
NSMutableString *filePath = [NSMutableString stringWithString:sharedItems];
NSString *docsPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *imagePath = [docsPath stringByAppendingPathComponent:filePath];
NSURL *imageUrl = [NSURL fileURLWithPath:imagePath];
NSData *imageData = [NSData dataWithContentsOfURL:imageUrl];
UIImage *shareImage = [UIImage imageWithData:imageData];
UIActivityViewController *activityViewController =
[[UIActivityViewController alloc] initWithActivityItems:@[ shareImage ]
applicationActivities:nil];
[controller presentViewController:activityViewController animated:YES completion:nil];
}
@end
MainActivity.java
package com.example.share;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import java.io.File;
import io.flutter.app.FlutterActivity;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugins.GeneratedPluginRegistrant;
import android.support.v4.content.FileProvider;
public class MainActivity extends FlutterActivity {
private static final String SHARE_CHANNEL = "channel:me.albie.share/share";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GeneratedPluginRegistrant.registerWith(this);
new MethodChannel(this.getFlutterView(), SHARE_CHANNEL).setMethodCallHandler(new MethodChannel.MethodCallHandler() {
public final void onMethodCall(MethodCall methodCall, MethodChannel.Result result) {
if (methodCall.method.equals("shareFile")) {
shareFile((String) methodCall.arguments);
}
}
});
}
private void shareFile(String path) {
File imageFile = new File(this.getApplicationContext().getCacheDir(), path);
Uri contentUri = FileProvider.getUriForFile(this, "me.albie.share", imageFile);
Intent shareIntent = new Intent(Intent.ACTION_SEND);
shareIntent.setType("image/jpg");
shareIntent.putExtra(Intent.EXTRA_STREAM, contentUri);
this.startActivity(Intent.createChooser(shareIntent, "Share image using"));
}
}
AndroidManifest.xml
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="me.albie.share"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
</provider>
xml/file_paths.xml
<?xml version="1.0" encoding="utf-8"?>
<paths>
<cache-path name="images" path="/"/>
</paths>
build.gradle (app)
dependencies {
...
implementation 'com.android.support:support-v4:27.1.1'
}
