Facebook插件（facebook开发者平台）

请看原文更详细：http://tryenough.com/flutter-plugin-share

这个活生生的例子会教你开发flutter插件，功能是封装Android和iOS端的分享到facebook和twitter的flutter接口。使用的分别是两端的系统分享功能，不需要集成facebook和twitter 的 sdk。

例子插件网址：https://pub.dartlang.org/packages/flutter_share_go#-readme-tab-

展示一下样式：

ios 中分享到facebook：

android中分享到facebook

请看原文更详细：http://tryenough.com/flutter-plugin-share

开始开发插件

步骤一：创建插件项目

这里用的Android studio创建的项目，可以直接创建flutter plugin项目，你也可以用命令创建：

flutter create –org com.example –template=plugin \\\”plugin_name\\\”

将上面的“plugin_name”换成你的插件名字就行了，我这个插件名字叫flutter_share_go,所以命令就是：

flutter create –org com.example –template=plugin flutter_share_go

这里没有支持swift和kotlin，原因是使用插件的很多项目可能并不支持，以免造成不必要的麻烦，但是你仍然可以选择支持，命令如下：

flutter create –template=plugin -i swift -a kotlin flutter_share_go

查看创建好的项目结构：

Android文件夹中：Android端原生的代码

iOS文件夹中：iOS端原生的代码

example文件：是方便测试你的插件的例子代码

lib文件：插件对原生接口的封装，也就是直接在dart代码中调用的接口

分别在Android studio和xcode中编辑Android和iOS代码

先在Android studio中编写Android部分代码

用Android studio打开项目中的android文件夹，因为此时缺少flutter库依赖，需要配置一下：

在项目根目录建立一个libs文件夹，用来存放flutter库，flutter库可以到你电脑的flutter sdk路径中寻找：

/bin/cache/artifacts/engine

在engine路径下有很多的android支持库，随便拷贝一个Android平台的库到libs文件夹下，右键flutter.jar，弹出菜单选择Add As Library…。这里不用担心，我们等下设置一下让它只是编译时使用，不会打包进来。

然后点击菜单File/Project Structure…，找到flutter_text_plugin的Dependencies中，将flutter库的Scope从Implementation改成Compile Only。

开始添加Android代码

添加如下两个文件：

PackageUtils.java 工具类

package com.doglobal.flutter_share_go;

import android.content.Context;

import android.content.Intent;

import android.content.pm.PackageManager;

import android.net.Uri;

public class PackageUtils {

public static boolean isPkgInstalled {

if )

return false;

android.content.pm.ApplicationInfo info = null;

try {

info = context.getPackageManager.getApplicationInfo;

return info != null;

} catch {

return false;

}

}

public static void goDownloadPage {

Context app = context.getApplicationContext;

try {

Intent intent = new Intent);

intent.addFlags;

app.startActivity;

} catch {

Intent intent = new Intent);

intent.addFlags;

app.startActivity;

}

}

}

ShareHelper.java 工具类

package com.doglobal.flutter_share_go;

import android.app.Activity;

import android.content.Intent;

import android.text.TextUtils;

public class ShareHelper {

public static final String CHANNEL_FACEBOOK_PKG_NAME = \\\”com.facebook.katana\\\”;

public static final String CHANNEL_TWITTER_PKG_NAME = \\\”com.twitter.android\\\”;

public static void shareMain {

shareText;

}

public static void shareTextToChannel {

if ) {

shareText;

} else {

PackageUtils.goDownloadPage;

}

}

/**

* @param dlgTitle 选择弹框标题

* @param subject 分享主题

* @param shareText 分享内容

*/

public static void shareText {

if ) {

return;

}

String content = shareText + \\\”: \\\” + shareUrl + \\\” .\\\”;

Intent intent = new Intent;

intent.addFlags;

intent.setType;

if ) {

intent.putExtra;

}

intent.putExtra;

if ) {

intent.setPackage;

}

// 设置弹出框标题

if ) { // 自定义标题

Intent chooser = Intent.createChooser;

chooser.addFlags;

activity.startActivity;

} else { // 系统默认标题

activity.startActivity;

}

}

}

然后在FlutterShareGoPlugin.java文件中添加调用逻辑。

这个文件就是java端对dart端的调用接口。我们先来看下代码，再进行解析：

package com.doglobal.flutter_share_go;import android.app.Activity;import io.flutter.plugin.common.MethodCall;import io.flutter.plugin.common.MethodChannel;import io.flutter.plugin.common.MethodChannel.MethodCallHandler;import io.flutter.plugin.common.MethodChannel.Result;import io.flutter.plugin.common.PluginRegistry.Registrar;/** FlutterShareGoPlugin */public class FlutterShareGoPlugin implements MethodCallHandler { private Activity mActivity; //分析一 private FlutterShareGoPlugin { mActivity = context; } /** Plugin registration. */ public static void registerWith { final MethodChannel channel = new MethodChannel, \\\”flutter_share_go\\\”); channel.setMethodCallHandler)); } @Override public void onMethodCall { if ) { result.success; } else if ) { //分析二 String content = call.argument; String shareUrl = call.argument; ShareHelper.shareTextToChannel; } else if ) { String content = call.argument; String shareUrl = call.argument; ShareHelper.shareTextToChannel; } else { result.notImplemented; } }}

请看原文更详细：http://tryenough.com/flutter-plugin-share分析一我们添加一个构造方法，用来存储activity分析二在方法onMethodCall中根据dart传递过来的方法名调用java端不同的代码逻辑

至此，Android端代码就告一段落了。

iOS端开发，在xcode中开发

如图，我们在Android studio中打开一个iOS文件，在右上角会有用xcode打开的按钮，我们点击打开就可以用xcode编辑了。

打开项目添加上图中的文件：

FlutterShareGoPlugin.m文件

#import \\\”FlutterShareGoPlugin.h\\\”

#import \\\”ShareHelper.h\\\”

#import <Social/Social.h>

@interface FlutterShareGoPlugin

@property UIViewController * rootViewController;

@end

@implementation FlutterShareGoPlugin

+ registerWithRegistrar:registrar {

FlutterMethodChannel* channel = [FlutterMethodChannel

methodChannelWithName:@\\\”flutter_share_go\\\”

binaryMessenger:[registrar messenger]];

FlutterShareGoPlugin* instance = [[FlutterShareGoPlugin alloc] init];

[registrar addMethodCallDelegate:instance channel:channel];

}

– handleMethodCall:call result:result {

if {

result;

}

else if {

NSDictionary *arguments = [call arguments];

NSString * shareContent = arguments[@\\\”shareContent\\\”];

NSString * shareUrl = arguments[@\\\”shareUrl\\\”];

[ShareHelper shareToPlatformType:SLServiceTypeFacebook withContent:shareContent withShareUrl:shareUrl];

result;

}

else if {

NSDictionary *arguments = [call arguments];

NSString * shareContent = arguments[@\\\”shareContent\\\”];

NSString * shareUrl = arguments[@\\\”shareUrl\\\”];

[ShareHelper shareToPlatformType:SLServiceTypeTwitter withContent:shareContent withShareUrl:shareUrl];

result;

}

else {

result;

}

}

@end

PackageUtil.h

#import <Foundation/Foundation.h>NS_ASSUME_NONNULL_BEGIN@interface PackageUtil : NSObject// Is intalled specific app or not+ isInstalledWithUrlScheme:urlScheme;@endNS_ASSUME_NONNULL_END

PackageUtil.m

#import \\\”PackageUtil.h\\\”

@implementation PackageUtil

+ isInstalledWithUrlScheme:urlScheme {

if {

return false;

}

return [[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:urlScheme]];

}

@end

ShareHelper.h

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface ShareHelper : NSObject

+shareToPlatformType:platformType withContent:content withShareUrl:url;

@end

NS_ASSUME_NONNULL_END

ShareHelper.m

#import \\\”ShareHelper.h\\\”#import <Social/Social.h>#import \\\”PackageUtil.h\\\”@implementation ShareHelper/* SOCIAL_EXTERN NSString *const SLServiceTypeTwitter NS_AVAILABLE;//Twitter SOCIAL_EXTERN NSString *const SLServiceTypeFacebook NS_AVAILABLE;//Facebook SOCIAL_EXTERN NSString *const SLServiceTypeSinaWeibo NS_AVAILABLE; SOCIAL_EXTERN NSString *const SLServiceTypeTencentWeibo NS_AVAILABLE; SOCIAL_EXTERN NSString *const SLServiceTypeLinkedIn NS_AVAILABLE; */+shareToPlatformType:platformType withContent:content withShareUrl:url{ if { NSLog; return; } if { [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@\\\”itms-apps://itunes.apple.com/app/id284882215\\\”]]; NSLog; return; } if { [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@\\\”itms-apps://itunes.apple.com/app/id333903271\\\”]]; NSLog; return; } // create controller for ServiceType SLComposeViewController *composeVC = [SLComposeViewController composeViewControllerForServiceType:platformType]; // image // [composeVC addImage:[UIImage imageNamed:@\\\”Nameless\\\”]]; // content [composeVC setInitialText:content]; // share url [composeVC addURL:[NSURL URLWithString:url]]; // share controller if { UINavigationController *vc = [[UIApplication sharedApplication] keyWindow].rootViewController; [vc pushViewController:composeVC animated:YES]; } else { UINavigationController *vc = [[UIApplication sharedApplication] keyWindow].rootViewController; [vc presentViewController:composeVC animated:YES completion:nil]; } // callback user hanlder composeVC.completionHandler = ^{ if { } else if { } };}@end

请看原文更详细：http://tryenough.com/flutter-plugin-share

蕞后需要我们在plist文件中添加白名单，用于iOS9适配，查看是否安装了facebook和twitter：

iOS 部分代码到此也告一段落了。

添加flutter接口，供dart代码调用

打开项目中lib文件夹下的flutter_share_go文件

FlutterShareGo.dart

import \’dart:async\’;

import \’package:flutter/services.dart\’;

class FlutterShareGo {

static const MethodChannel _channel =

const MethodChannel;

static Future<String> get platformVersion async {

final String version = await _channel.invokeMethod;

return version;

}

static Future<void> shareToFBPlatform async {

assert;

assert;

final Map<String, dynamic> params = <String, dynamic> {

\’shareContent\’: shareContent,

\’shareUrl\’:shareUrl,

};

await _channel.invokeMethod;

}

static Future<void> shareToTwitterPlatform async {

assert;

assert;

final Map<String, dynamic> params = <String, dynamic> {

\’shareContent\’: shareContent,

\’shareUrl\’:shareUrl,

};

await _channel.invokeMethod;

}

}

flutter端代码就告一段落了。

测试插件：

打开项目中example文件下的main.dart：

main.dart

import \’package:flutter/material.dart\’;import \’dart:async\’;import \’package:flutter/services.dart\’;import \’package:flutter_share_go/flutter_share_go.dart\’;void main => runApp);class MyApp extends StatefulWidget { @override _MyAppState createState => _MyAppState;}class _MyAppState extends State<MyApp> { String _platformVersion = \’Unknown\’; @override void initState { super.initState; initPlatformState; } // Platform messages are asynchronous, so we initialize in an async method. Future<void> initPlatformState async { String platformVersion; // Platform messages may fail, so we use a try/catch PlatformException. try { platformVersion = await FlutterShareGo.platformVersion; } on PlatformException { platformVersion = \’Failed to get platform version.\’; } // If the widget was removed from the tree while the asynchronous platform // message was in flight, we want to discard the reply rather than calling // setState to update our non-existent appearance. if return; setState { _platformVersion = platformVersion; }); } @override Widget build { return MaterialApp, ), body: Column, RaisedButton, color: Colors.red, onPressed: { FlutterShareGo.shareToFBPlatform; }, ) ], ), ), ); }}

运行就会出现文章蕞上面的效果了。祝你顺利。

蕞后发布可以参照如下步骤：

运行命令，并解决所有出现的问题：

flutter packages pub publish –dry-run

问题解决完就可以发布了，命令：

flutter packages pub publish

请看原文更详细：http://tryenough.com/flutter-plugin-share