如何使用Flutter在iOS和Android上共享图像？

Question

我想使用iOS和Android中的标准共享对话框共享图像.下面的代码主要来自https://pub.dartlang.org/packages/share,我将其用作起点(下面只有Dart和Objective-C).它目前只共享文本.

而不是Image,我不确定是最好的方法,如何将图像转换为Dart中的字节流并在iOS和Android中处理.

镖

static const _kShareChannel = const MethodChannel('example.test.com/share');
Future<Null> shareImage(Image image) {
  assert(image != null);
  return _kShareChannel.invokeMethod('shareImage', image);
}

Objective-C的

static NSString *const PLATFORM_CHANNEL = @"example.test.com/share";

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [GeneratedPluginRegistrant registerWithRegistry:self];

    FlutterViewController* controller = (FlutterViewController*)self.window.rootViewController;

    FlutterMethodChannel *shareChannel = [FlutterMethodChannel methodChannelWithName:PLATFORM_CHANNEL
                            binaryMessenger:controller];

    [shareChannel setMethodCallHandler:^(FlutterMethodCall *call, FlutterResult result) {
        if ([@"shareImage" isEqualToString:call.method]) {
            [self share:call.arguments withController:[UIApplication sharedApplication].keyWindow.rootViewController];
            result(nil);
        } else {
            result([FlutterError errorWithCode:@"UNKNOWN_METHOD"
                                       message:@"Unknown share method called"
                                       details:nil]);
        }
    }];
    return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

- (void)share:(id)sharedItems withController:(UIViewController *)controller {
    UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:@[ sharedItems ]
                                  applicationActivities:nil];
    [controller presentViewController:activityViewController animated:YES completion:nil];
}

Answer 1

下面将允许您使用UIActivityViewControlleriOS上的文件(特别是此示例中的图像)和Android上的共享意图.

FileProvider概述(Android)

pubspec.yaml如果是本地(本例中为image.jpg),则更新以引用您的图像,并使用该path_provider插件访问文件系统.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中

<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'
}

Answer 2

我们将该功能放入一个插件中：https : //pub.dartlang.org/packages/esys_flutter_share。

镖：

final ByteData bytes = await rootBundle.load('assets/image1.png');
await Share.file('esys image', 'esys.png', bytes.buffer.asUint8List(), 'image/png');

Answer 3

尝试使用wc_flutter_share。

https://pub.dev/packages/wc_flutter_share

这个插件支持分享图片、文字和主题。这个插件的独特之处在于它还支持同时共享图像和文本，在我写这个答案时其他插件不支持。

Answer 4

感谢@albert-lardizabal 上面的代码，它工作得非常完美！！我不得不将它翻译成 Swift 和 Kotlin，所以这是代码，以防你们需要它：

迅速：

override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?
    ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)


    let shareChannelName = "channel:me.albie.share/share";
    let controller:FlutterViewController = self.window?.rootViewController as! FlutterViewController;
    let shareChannel:FlutterMethodChannel = FlutterMethodChannel.init(name: shareChannelName, binaryMessenger: controller);

    shareChannel.setMethodCallHandler({
        (call: FlutterMethodCall, result: FlutterResult) -> Void in
        if (call.method == "shareFile") {
            self.shareFile(sharedItems: call.arguments!,controller: controller);
        }
    });


    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
}

func shareFile(sharedItems:Any, controller:UIViewController) {
    let filePath:NSMutableString = NSMutableString.init(string: sharedItems as! String);
    let docsPath:NSString = (NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.cachesDirectory, FileManager.SearchPathDomainMask.userDomainMask, true)[0]) as NSString;
    let imagePath = docsPath.appendingPathComponent(filePath as String);
    let imageUrl = URL.init(fileURLWithPath: imagePath, relativeTo: nil);
    do {
        let imageData = try Data.init(contentsOf: imageUrl);
        let shareImage = UIImage.init(data: imageData);
        let activityViewController:UIActivityViewController = UIActivityViewController.init(activityItems: [shareImage!], applicationActivities: nil);
        controller.present(activityViewController, animated: true, completion: nil);
    } catch let error {
        print(error.localizedDescription);
    }
}

科特林：

    override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    GeneratedPluginRegistrant.registerWith(this)

    MethodChannel(flutterView,"channel:me.albie.share/share").setMethodCallHandler { methodCall, _ ->
        if (methodCall.method == "shareFile") {
            shareFile(methodCall.arguments as String)
        }
    }
}

private fun shareFile(path:String) {
    val imageFile = File(this.applicationContext.cacheDir,path)
    val contentUri = FileProvider.getUriForFile(this,"me.albie.share",imageFile)

    val shareIntent = Intent()
    shareIntent.action = Intent.ACTION_SEND
    shareIntent.type="image/jpg"
    shareIntent.putExtra(Intent.EXTRA_STREAM, contentUri)
    startActivity(Intent.createChooser(shareIntent,"Compartir usando"))
}