安卓原生截屏开发flutter插件

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RepaintBoundary作为flutter截屏控件，截屏内容无法截取到带有播放器的播放内容页面，所以考虑调用安卓原生的截屏

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插件目录结构

最开始命令行创建
flutter create --org com.example --template=plugin --platforms=android,ios -a java my_screenshot

在工程 	的android/src/main/java/com/example/my_screenshot/MyScreenshotPlugin

package com.example.my_screenshot;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.util.Log;
import android.view.View;

import androidx.annotation.NonNull;

import java.io.File;
import java.io.FileOutputStream;
import java.util.Date;

import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.embedding.engine.plugins.activity.ActivityAware;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
import io.flutter.embedding.engine.renderer.FlutterRenderer;
import io.flutter.plugin.common.BinaryMessenger;
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;
import io.flutter.view.FlutterView;

/**
 * FlutterNativeScreenshotPlugin
 */
public class MyScreenshotPlugin
        implements FlutterPlugin, MethodCallHandler, ActivityAware {
    
    
  private static final String TAG = "FNSPlugin";
  //声明context对象
  private Context context;
  //声明channel
  private MethodChannel channel;
  //声明activity对象
  private Activity activity;
  //声明对象
  private Object renderer;
  //声明状态
  private boolean ssError = false;
  //声明图片的路径
  private String ssPath;

  // Default constructor for old registrar
  public MyScreenshotPlugin() {
    
    
  } // FlutterNativeScreenshotPlugin()

  // Condensed logic to initialize the plugin
  private void initPlugin(Context context, BinaryMessenger messenger, Activity activity,
                          Object renderer) {
    
    
    this.context = context;
    this.activity = activity;
    this.renderer = renderer;

    this.channel = new MethodChannel(messenger, "my_screenshot");
    this.channel.setMethodCallHandler(this);
  } // initPlugin()

  //**************************注册插件******************************************
  @Override
  public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
    
    
    Log.println(Log.INFO, TAG, "Using *NEW* registrar method!");

    initPlugin(
            flutterPluginBinding.getApplicationContext(),
            flutterPluginBinding.getBinaryMessenger(),
            null,
            flutterPluginBinding.getFlutterEngine().getRenderer()
    ); // initPlugin()
  } // onAttachedToEngine()

  // New v2 listener methods
  @Override
  public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
    
    
    this.channel.setMethodCallHandler(null);
    this.channel = null;
    this.context = null;
  } // onDetachedFromEngine()

  //旧的注册方法
  //插件仍应包含静态的 registerWith() 方法，
  //与不使用 v2 embedding 的应用程序保持兼容。
  public static void registerWith(Registrar registrar) {
    
    
    Log.println(Log.INFO, TAG, "Using *OLD* registrar method!");

    MyScreenshotPlugin instance = new MyScreenshotPlugin();

    instance.initPlugin(
            registrar.context(),
            registrar.messenger(),
            registrar.activity(),
            registrar.view()
    ); // initPlugin()
  } // registerWith()

  //***************************************在插件中引入activity对象***************
  // Activity condensed methods
  private void attachActivity(ActivityPluginBinding binding) {
    
    
    //获取当前flutter页面所处的Activity.
    this.activity = binding.getActivity();
  } // attachActivity()

  private void detachActivity() {
    
    
    this.activity = null;
  } // attachActivity()


  // Activity listener methods
  @Override
  public void onAttachedToActivity(ActivityPluginBinding binding) {
    
    
    attachActivity(binding);
  } // onAttachedToActivity()

  @Override
  public void onDetachedFromActivityForConfigChanges() {
    
    
    detachActivity();
  } // onDetachedFromActivityForConfigChanges()

  @Override
  public void onReattachedToActivityForConfigChanges(ActivityPluginBinding binding) {
    
    
    attachActivity(binding);
  } // onReattachedToActivityForConfigChanges()

  @Override
  public void onDetachedFromActivity() {
    
    
    detachActivity();
  } // onDetachedFromActivity()


  //************************方法回调，这里主要是回调管道调用的方法***************************
  @Override
  public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
    
    
    if (!call.method.equals("takeScreenshot")) {
    
    
      Log.println(Log.ERROR, TAG, "Method not implemented!");
      result.notImplemented();
      return;
    }
    takeScreenshotOld();
    result.success(ssPath);

  } // onMethodCall()

  //*************************封装自己的方法*************************************
  //用当前时间命名图片
  private String getScreenshotName() {
    
    
    java.text.SimpleDateFormat sf = new java.text.SimpleDateFormat("yyyyMMddHHmmss");
    String sDate = sf.format(new Date());

    return "flutter_native_screenshot-" + sDate + ".png";
  } // getScreenshotName()

  //获取
  private String getScreenshotPath() {
    
    
    String pathTemporary = context.getCacheDir().getPath();
    Log.println(Log.INFO, TAG, "path temporary: " + pathTemporary);

    String dirPath = pathTemporary + "/" + getScreenshotName();

    Log.println(Log.INFO, TAG, "Built ScreeshotPath: " + dirPath);

    return dirPath;
  } // getScreenshotPath()

  private String writeBitmap(Bitmap bitmap) {
    
    
    try {
    
    
      String path = getScreenshotPath();
      File imageFile = new File(path);
      FileOutputStream oStream = new FileOutputStream(imageFile);

      bitmap.compress(Bitmap.CompressFormat.PNG, 100, oStream);
      oStream.flush();
      oStream.close();

      return path;
    } catch (Exception ex) {
    
    
      Log.println(Log.INFO, TAG, "Error writing bitmap: " + ex.getMessage());
    }

    return null;
  } // writeBitmap()

  private void reloadMedia() {
    
    
    try {
    
    
      //扫描媒体文件
      Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
      File file = new File(this.ssPath);
      Uri uri = Uri.fromFile(file);

      intent.setData(uri);
      this.activity.sendBroadcast(intent);
    } catch (Exception ex) {
    
    
      Log.println(Log.INFO, TAG, "Error reloading media lib: " + ex.getMessage());
    }
  } // reloadMedia()

  private void takeScreenshotOld() {
    
    
    Log.println(Log.INFO, TAG, "Trying to take screenshot [old way]");

    try {
    
    
      //使用getWindow().getDecorView().getRootView()是获取当前屏幕的activity
      View view = this.activity.getWindow().getDecorView().getRootView();
      //从ImageView对象获取图像之前
      view.setDrawingCacheEnabled(true);

      Bitmap bitmap = null;
      if (this.renderer.getClass() == FlutterView.class) {
    
    
        bitmap = ((FlutterView) this.renderer).getBitmap();
      } else if (this.renderer.getClass() == FlutterRenderer.class) {
    
    
        bitmap = ((FlutterRenderer) this.renderer).getBitmap();
      }

      if (bitmap == null) {
    
    
        this.ssError = true;
        this.ssPath = null;

        Log.println(Log.INFO, TAG, "The bitmap cannot be created :(");

        return;
      } // if
      //从ImageView对象获取图像之后
      view.setDrawingCacheEnabled(false);
      //这样才能以清空画图缓冲区否则会导致下次还是上次的图
      String path = writeBitmap(bitmap);
      if (path == null || path.isEmpty()) {
    
    
        this.ssError = true;
        this.ssPath = null;

        Log.println(Log.INFO, TAG, "The bitmap cannot be written, invalid path.");

        return;
      } // if

      this.ssError = false;
      this.ssPath = path;

      reloadMedia();
    } catch (Exception ex) {
    
    
      Log.println(Log.INFO, TAG, "Error taking screenshot: " + ex.getMessage());
    }
  } // takeScreenshot()
}

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AndroidManifest.xml的配置

在你的flutter工程android下的AndroidManifest.xml添加权限

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.example.my_screenshot">

    <!-- 添加权限-->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

</manifest>

在插件lib封装

import 'dart:async';

import 'package:flutter/services.dart';

class MyScreenshot {
  //这里MethodChannel(‘通道名字’)
  //通道名字MyScreenshotPlugin里面的的通道名字要一致
  static const MethodChannel _channel = const MethodChannel('my_screenshot');

  static Future<String> takeScreenshot() async {
    final String path = await _channel.invokeMethod('takeScreenshot');
    print('调用成功');
    return path;
  }
}

总结

可用，简单
调用方法
import之后
String path = await MyScreenshot.takeScreenshot();

如果还需要做后续处理比如说将文件数据读取出来
可以作为image，或者盒子背景或者通过dio上传到网上

//提醒一下：这里的widget.picturePath实际上是上述的path
      File _dataFile = File(widget.picturePath);
      Uint8List _screenImgData = await _dataFile.readAsBytesSync();
      //在widget那里可以通过
      Image.memory(_screenImgData);
      //或者作为盒子的背景
      Container(
         // decoration: BoxDecoration(color: Colors.white),
         decoration: BoxDecoration(
             image: DecorationImage(
                 image: MemoryImage(
                   _screenImgData,
                 ),
                 fit: BoxFit.fill)),
       )
       //或者上传(这里的 NetUtils.postFormData实际上是对dio进行了一层封装）
       NetUtils.postFormData(
              Api.saveOrshareImg,
              {"file": await MultipartFile.fromFile(widget.picturePath, filename: 'save.png')},
              success: (response) {
                print(response);
                var jsonData = json.decode(response);
                var res = ResponseModel.fromJson(jsonData);
                if (res.status == 0) {;
                  print('success');
                  // }
                } else {
                  print("${res.info.detail}${res.info.message}");
                }
              },
              fail: (e) {
                print(e.toString());
              },
            );

下载
百度网盘
提取码：0001

注意事项：
环境是在

• sdk: “>=2.7.0 < 3.0.0”
• flutter: “>=1.20.0”

可先下载好后cd到example 然后flutter run一次看看能否运行
若能运行则可以在你的flutter工程的pubspec.yaml
注册插件

  my_screenshot:
  	path: 你的路径（绝对路径或者相对路径都可）