Question

我正在遵循这个blog 来从图库中选择多张图片。对于IOS，我正在使用GMImagePicker从图库中选择多张图片。（在博客中建议使用elcimagepicker，但现在在Nuget Store中不可用）

我经历了GMImagePicker usage 部分，但是没有找到如何将所选图像添加到List并在MessagingCenter中传递该值的方法（例如android实现）。在该用法部分中，仅讲述选择器设置。有人请给我任何使用此功能的示例代码吗？

Lucas Zhang - MSFT，您好，我尝试了您的代码，但有一个问题。在这里，您仅通过messagecenter传递一个文件路径，因此我应该使用列表发送多个文件路径吗？

我正在将图片路径作为string List从android传递。请查看下面添加的android部件代码。我应该在IOS中这样做吗？

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
    {
        base.OnActivityResult(requestCode, resultCode, data);

        if (resultCode == Result.Ok)
        {
            List<string> images = new List<string>();

            if (data != null)
            {
                ClipData clipData = data.ClipData;
                if (clipData != null)
                {
                    for (int i = 0; i < clipData.ItemCount; i++)
                    {
                        ClipData.Item item = clipData.GetItemAt(i);
                        Android.Net.Uri uri = item.Uri;
                        var path = GetRealPathFromURI(uri);

                        if (path != null)
                        {
                            //Rotate Image
                            var imageRotated = ImageHelpers.RotateImage(path);
                            var newPath = ImageHelpers.SaveFile("TmpPictures", imageRotated, System.DateTime.Now.ToString("yyyyMMddHHmmssfff"));
                            images.Add(newPath);
                        }
                    }
                }
                else
                {
                    Android.Net.Uri uri = data.Data;
                    var path = GetRealPathFromURI(uri);

                    if (path != null)
                    {
                        //Rotate Image
                        var imageRotated = ImageHelpers.RotateImage(path);
                        var newPath = ImageHelpers.SaveFile("TmpPictures", imageRotated, System.DateTime.Now.ToString("yyyyMMddHHmmssfff"));
                        images.Add(newPath);
                    }
                }

                MessagingCenter.Send<App, List<string>>((App)Xamarin.Forms.Application.Current, "ImagesSelected", images);
            }
        }
    }

我也遇到了错误，屏幕截图添加到下面：

Answer 1

GMImagePicker 将返回包含import urllib.parse def gen_uri_paths(baseURL, append_paths): res = urllib.parse.urlparse(baseURL) uri_paths = [] for p in append_paths: u = list(res) u[2] += p uri_paths.append(urllib.parse.ParseResult(*u).geturl()) return uri_paths # Returns ['https://example.com/p_1', 'https://example.com/p_2', 'https://example.com/p_3', 'https://example.com/a_1'] gen_uri_paths("https://example.com", ["p_1", "p_2", "p_3", "a_1"])的列表。因此，您可以首先获取图像的filePath，然后使用PHAsset和{{1}将它们传递到表单}。请参考以下代码。

在表单中，创建一个界面

MessagingCenter

在iOS项目中

DependencyService

在您的contentPages中

using System;

namespace app1
{
  public interface ISelectMultiImage
  {
    void SelectedImage();
  }
}

如果要选择图像，请调用方法

using System;
using Xamarin.Forms;
using UIKit;
using GMImagePicker;
using Photos;
using Foundation;

[assembly:Dependency(typeof(SelectMultiImageImplementation))]
namespace xxx.iOS
{
  public class SelectMultiImageImplementation:ISelectMultiImage
  {
    public SelectMultiImageImplementation()
    {
    }


    string Save(UIImage image, string name)
    {
        var documentsDirectory = Environment.GetFolderPath
                              (Environment.SpecialFolder.Personal);
        string jpgFilename = System.IO.Path.Combine(documentsDirectory, name); // hardcoded filename, overwritten each time
        NSData imgData = image.AsJPEG();
        if (imgData.Save(jpgFilename, false, out NSError err))
        {
            return jpgFilename;
        }
        else
        {
            Console.WriteLine("NOT saved as " + jpgFilename + " because" + err.LocalizedDescription);
            return null;
        }
    }

    public void SelectedImage()
    {

        var picker = new GMImagePickerController();
        picker.FinishedPickingAssets += (s, args) => {


            PHAsset[] assets = args.Assets;



            foreach (PHAsset asset in assets)
            {
                PHImageManager.DefaultManager.RequestImageData(asset, null, (NSData data, NSString dataUti, UIImageOrientation orientation, NSDictionary info) =>
                {
                    NSUrl url = NSUrl.FromString(info.ValueForKey(new NSString("PHImageFileURLKey")).ToString());

                    string[] strs = url.Split("/");


                    UIImage image = UIImage.LoadFromData(data);

                    string file = Save(UIImage.LoadFromData(data), strs[strs.Length - 1]);


                    MessagingCenter.Send<Object, string>(this, "ImagesSelected", file);

                }
                );

            }

        };
       UIApplication.SharedApplication.KeyWindow.RootViewController.PresentViewController(picker, true,null);

    }
  }
}

如何在Xamarin IOS中使用GMImagePicker从图库中选择多张图片？

1 个答案: