需要用MonoDroid和MVVMCross拍摄照片的一个例子

Question

任何人都可以指点我的示例拍摄照片并使用MVVMCross存储？

我一直在寻找，但只找到了这个：

• Monodroid Take a picture with Camera（没有实现MVVMCross）

• Video Recording（这是视频，我不能让它工作：S ）

• The Oficialy Recipe Example（它的作品，但没有实现MVVMCross）

谢谢！

已解决！谢谢！
引用未来：（采用主科）
积分斯图尔特，我只是改变了代码与我的现实工作

using Cirrious.MvvmCross.ExtensionMethods; 
using Cirrious.MvvmCross.Interfaces.Platform.Tasks; 
using Cirrious.MvvmCross.Interfaces.ServiceProvider; 
using SIGEP.DummyService; 
using SIGEP.Mobile.Core.Interfaces; 


namespace SIGEP.Mobile.Core.Models 
{ 
public class PhotoService : IMvxServiceConsumer<IMvxPictureChooserTask> 
{ 
    private const int MaxPixelDimension = 1024; 
    private const int DefaultJpegQuality = 92; 

    public void GetNewPhoto() 
    { 
     this.GetService<IMvxPictureChooserTask>().TakePicture(
      MaxPixelDimension, 
      DefaultJpegQuality, 
      HandlePhotoAvailable, 
      () => { /* cancel is ignored */ }); 

    } 

    public event EventHandler<PhotoStreamEventArgs> PhotoStreamAvailable; 

    private void HandlePhotoAvailable(Stream pictureStream) 
    { 
     var handler = PhotoStreamAvailable; 
     if (handler != null) 
     { 
      handler(this, new PhotoStreamEventArgs() { PictureStream = pictureStream, OnSucessGettingPhotoFileName = OnSucessGettingPhotoFileName }); 
     } 
    } 



    public static void TakePhoto(Action<string> successFileName, Action<Exception> error) 
    { 
     var service = new PhotoService(); 
     service.OnSucessGettingPhotoFileName = successFileName; 
     service.OnError = error; 
     service.GetNewPhoto(); 
     service.PhotoStreamAvailable += new EventHandler<PhotoStreamEventArgs>(service_PhotoStreamAvailable); 
    } 

    static void service_PhotoStreamAvailable(object sender, PhotoStreamEventArgs e) 
    { 
     //grava pra ficheiro!!! 
     var directory = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments); 
     var filename = Path.Combine(directory, "photo.jpeg"); 
     string saveTo = filename; 
     FileStream writeStream = new FileStream(saveTo, FileMode.Create, FileAccess.Write); 
     ReadWriteStream(e.PictureStream, writeStream); 

     e.OnSucessGettingPhotoFileName(filename); 

    } 
    private static void ReadWriteStream(Stream readStream, Stream writeStream) 
    { 
     int Length = 256; 
     Byte[] buffer = new Byte[Length]; 
     int bytesRead = readStream.Read(buffer, 0, Length); 
     // write the required bytes 
     while (bytesRead > 0) 
     { 
      writeStream.Write(buffer, 0, bytesRead); 
      bytesRead = readStream.Read(buffer, 0, Length); 
     } 
     readStream.Close(); 
     writeStream.Close(); 
    } 

    public Action<string> OnSucessGettingPhotoFileName { get; set; } 
    public Action<Exception> OnError { get; set; } 
} 

[Serializable] 
[ComVisible(true)] 
public class PhotoStreamEventArgs : EventArgs 
{ 
    public Stream PictureStream { get; set; } 

    public Action<string> OnSucessGettingPhotoFileName { get; set; } 
} 
} 

Answer 1

我通常使用实现服务内置IMvxPictureChooserTask（这是一个插件，如果使用vNext）：

using Cirrious.MvvmCross.ExtensionMethods; 
using Cirrious.MvvmCross.Interfaces.Platform.Tasks; 
using Cirrious.MvvmCross.Interfaces.ServiceProvider; 

public class PhotoService 
    : IMvxServiceConsumer<IMvxPictureChooserTask> 
    , IPhotoService 
{ 
    private const int MaxPixelDimension = 1024; 
    private const int DefaultJpegQuality = 92; 

    public void GetNewPhoto() 
    { 
     Trace.Info("Get a new photo started."); 

     this.GetService<IMvxPictureChooserTask>().TakePicture(
      MaxPixelDimension, 
      DefaultJpegQuality, 
      HandlePhotoAvailable, 
      () => { /* cancel is ignored */ }); 
    } 

    public event EventHandler<PhotoStreamEventArgs> PhotoStreamAvailable; 

    private void HandlePhotoAvailable(Stream pictureStream) 
    { 
     Trace.Info("Picture available"); 
     var handler = PhotoStreamAvailable; 
     if (handler != null) 
     { 
      handler(this, new PhotoStreamEventArgs() { PictureStream = pictureStream }); 
     } 
    } 
} 

我一般注册这个服务在启动期间一个单，然后从一个ViewModel IComman调用它d处理程序。使用这种服务

---

一个应用程序是Blooor样本 - 见BaseEditProductViewModel.cs - 这是不是一个样我有什么做的，但我相信它带来了两个拍照和斑马线 - 无论是使用外部服务。

---

一个警告：在MonoDroid的，你可以看到一些奇怪的/出乎意料的活动/视图模型的生命周期行为 - 基本上你可以看到，活动你从被卸载照片/拍摄照片的过程中，从记忆中抹去了。如果这发生在您的应用程序中，那么您可能需要开始查看如下问题：Saving Android Activity state using Save Instance State - 这不会在MvvmCross（尚未）中自动处理。

我相信布洛尔样本可能会遭遇这个问题 - 但用户是否会看到它在正常的应用程序使用是值得商榷的。

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至于IMvxPictureChooserTask服务替代方案，你也可以看看使用一些从Xamarin.Mobile跨平台的API - 见MvvmCross vnext : monodroid use a VideoView inside a plugin一个可能的起点 - 或为Android只有你可以轻松实现你的拥有。