如何使用Flutter在iOS和Android上共享图像？

如何使用Flutter在iOS和Android上共享图像？

以下内容可让您

UIActivityViewController

在iOS上使用文件（在此示例中为图像）发送邮件，并在Android上作为共享意向文件。

FileProvider概述（Android）

更新

pubspec.yaml

以引用您的图像（如果是本地的话）（在此示例中为image.jpg），并使用该

path_provider

插件来访问文件系统。https://pub.dartlang.org/packages/path_provider

主镖

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 AppDelegatestatic 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（应用程序）

dependencies {    ...    implementation 'com.android.support:support-v4:27.1.1'}