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MASA MAUI Plugin (八)Android相册多选照片(Intent 方式)

2023-02-22 14:00 https://my.oschina.net/u/5447363/blog/8106625 MASA技术团队 次阅读 条评论

背景

MAUI的出现,赋予了广大.Net开发者开发多平台应用的能力,MAUI 是Xamarin.Forms演变而来,但是相比Xamarin性能更好,可扩展性更强,结构更简单。但是MAUI对于平台相关的实现并不完整。所以MASA团队开展了一个实验性项目,意在对微软MAUI的补充和扩展

项目地址https://github.com/BlazorComponent/MASA.Blazor/tree/feature/Maui/src/Masa.Blazor.Maui.Plugin

每个功能都有单独的demo演示项目,考虑到app安装文件体积(虽然MAUI已经集成裁剪功能,但是该功能对于代码本身有影响),届时每一个功能都会以单独的nuget包的形式提供,方便测试,现在项目才刚刚开始,但是相信很快就会有可以交付的内容啦。

前言

本系列文章面向移动开发小白,从零开始进行平台相关功能开发,演示如何参考平台的官方文档使用MAUI技术来开发相应功能。

介绍

项目中有需要从相册多选图片的需求,MAUI提供的MediaPicker.PickPhotoAsync无多选功能,FilePicker.PickMultipleAsync虽然可以实现多选,但是多选文件需要长按,而且没有预览和返回按钮,用户交互效果不好。作为安卓开发小白,本人目前找到两种UI交互良好而且不需要定制选取界面的方法和大家分享。

一、MAUI实现方式演示效果

MediaPicker.Default.PickPhotoAsync 效果

在这里插入图片描述

FilePicker.Default.PickMultipleAsync 效果

在这里插入图片描述

二、实现方式

思路

https://developer.android.google.cn/about/versions/13/features/photopicker?hl=zh-cn

我们参考一下官方文档,下面为选择多张照片或者多个视频的示例

JAVA代码
// Launches photo picker in multi-select mode.
// This means that user can select multiple photos/videos, up to the limit
// specified by the app in the extra (10 in this example).
final int maxNumPhotosAndVideos = 10;
Intent intent = new Intent(MediaStore.ACTION_PICK_IMAGES);
intent.putExtra(MediaStore.EXTRA_PICK_IMAGES_MAX, maxNumPhotosAndVideos);
startActivityForResult(intent, PHOTO_PICKER_MULTI_SELECT_REQUEST_CODE);


处理照片选择器结果

JAVA代码
// onActivityResult() handles callbacks from the photo picker.
@Override
protected void onActivityResult(
    int requestCode, int resultCode, final Intent data) {

    if (resultCode != Activity.RESULT_OK) {
        // Handle error
        return;
    }

    switch(requestCode) {
        case REQUEST_PHOTO_PICKER_SINGLE_SELECT:
            // Get photo picker response for single select.
            Uri currentUri = data.getData();

            // Do stuff with the photo/video URI.
            return;
        case REQUEST_PHOTO_PICKER_MULTI_SELECT:
            // Get photo picker response for multi select
            for (int i = 0; i < data.getClipData().getItemCount(); i++) {
                Uri currentUri = data.getClipData().getItemAt(i).getUri();

                // Do stuff with each photo/video URI.
            }
            return;
    }
}


限定选择内容范围 默认情况下,照片选择器会既显示照片又显示视频。您还可以在 setType() 方法中设置 MIME 类型,以便按“仅显示照片”或“仅显示视频”进行过滤

JAVA代码
// Launches photo picker for videos only in single select mode.
Intent intent = new Intent(MediaStore.ACTION_PICK_IMAGES);
intent.setType("video/*");
startActivityForResult(intent, PHOTO_PICKER_VIDEO_SINGLE_SELECT_REQUEST_CODE);

// Apps can also change the mimeType to allow users to select
// images only - intent.setType("image/*");
// or a specific mimeType - intent.setType("image/gif");


总结流程如下: 1、通过Intent(MediaStore.ACTION_PICK_IMAGES) 初始化一个打开相册的Intent 2、intent.setType 设置过滤条件 3、通过startActivityForResult打开新的Activity(打开相册),并通过重写onActivityResult 获取选取照片的返回数据 4、从返回的Intent 中拿到文件的Uri从而获取文件内容 注意:在一个Activity中,可能会使用startActivityForResult() 方法打开多个不同的Activity处理不同的业务 ,这时可以在onActivityResult中通过requestCode区分不同业务。

编写实现代码

新建MAUI Blazor项目MediaPickSample,新建Service文件夹,添加IPhotoPickerService.cs接口,添加GetImageAsync1-3,前两种为使用MAUI的两种方式实现,用做对比,不过多介绍,本文重点关注Intent方式实现的GetImageAsync3。示例方法的返回值为文件名+文件base64的字典形式。

namespace MediaPickSample.Service
{
    public interface IPhotoPickerService
    {
        /// <summary>
        /// Maui-MediaPicker
        /// </summary>
        Task<Dictionary<string, string>> GetImageAsync1();

        /// <summary>
        /// MMaui-FilePicker
        /// </summary>
        Task<Dictionary<string, string>> GetImageAsync2();

        /// <summary>
        /// Intent
        /// </summary>
        Task<Dictionary<string, string>> GetImageAsync3();
    }
}


由于StartActivityForResult需要在MainActivity中调用,我们先定义一个MainActivity的静态示例Instance,方便在业务中使用。 编辑Platforms->Android->MainActivity.cs文件

    public class MainActivity : MauiAppCompatActivity
    {
        internal static MainActivity Instance { get; private set; }
        public static readonly int PickImageId = 1000;
        public TaskCompletionSource<Dictionary<string, string>> PickImageTaskCompletionSource { set; get; }
        
        protected override void OnCreate(Bundle savedInstanceState)
        {
            Instance = this;
            base.OnCreate(savedInstanceState);
        }

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

            if (requestCode == PickImageId)
            {
                if ((resultCode == Result.Ok) && (intent != null))
                {
                    var imageNames = intent.ClipData;

                    if (imageNames != null)
                    {
                        var uris = new List<Android.Net.Uri>();

                        for (int i = 0; i < imageNames.ItemCount; i++)
                        {
                            var imageUri = imageNames.GetItemAt(i).Uri;
                            uris.Add(imageUri);
                        }

                        var fileList = Instance.GetImageDicFromUris(uris);
                        PickImageTaskCompletionSource.SetResult(fileList);
                    }
                }
                else
                {
                    PickImageTaskCompletionSource.SetResult(new Dictionary<string, string>());
                }
            }
        }
    }


首先我们定义了MainActivity的静态实例Instance,并在OnCreate事件中赋值 然后添加重写方法OnActivityResult,通过requestCode == PickImageId判断是从相册选取多个文件的业务(我们关注的业务),通过intent.ClipData获取数据,然后遍历这些数据依次通过GetItemAt(i).Uri获取所有的文件Uri,然后再通过我们封装的GetImageDicFromUris方法获取所有文件的内容。GetImageDicFromUris方法如下

        protected Dictionary<string, string> GetImageDicFromUris(List<Android.Net.Uri> list)
        {
            Dictionary<string, string> fileList = new Dictionary<string, string>();
            for (int i = 0; i < list.Count; i++)
            {
                var imageUri = list[i];
                var documentFile = DocumentFile.FromSingleUri(Instance, imageUri);
                if (documentFile != null)
                {
                    using (var stream = Instance.ContentResolver.OpenInputStream(imageUri))
                    {
                        stream.Seek(0, SeekOrigin.Begin);
                        var bs = new byte[stream.Length];
                        var log = Convert.ToInt32(stream.Length);
                        stream.Read(bs, 0, log);
                        var base64Str = Convert.ToBase64String(bs);
                        fileList.Add($"{Guid.NewGuid()}.{Path.GetExtension(documentFile.Name)}", base64Str);
                    }
                }
            }
            return fileList;
        }


DocumentFile位于AndroidX.DocumentFile.Provider命名空间,FromSingleUri方法通过Uri返回DocumentFile,然后通过ContentResolver.OpenInputStream读出文件流 ContentResolver的内容比较多,可以参考官方文档,这里我们简单理解它是一个内容提供程序即可

https://developer.android.google.cn/guide/topics/providers/content-provider-basics?hl=zh-cn

下面开始实现IPhotoPickerService接口 在Platforms->Android 新建AndroidPhotoPickerService.cs

namespace MediaPickSample.PlatformsAndroid
{
    public class AndroidPhotoPickerService : IPhotoPickerService
    {
        /// <summary>
        /// Maui-MediaPicker
        /// </summary>
        public async Task<Dictionary<string, string>> GetImageAsync1()
        {
            ...
        }
        
        /// <summary>
        /// MMaui-FilePicker
        /// </summary>
        public async Task<Dictionary<string, string>> GetImageAsync2()
        {
            ...
        }
        
        /// <summary>
        /// Intent
        /// </summary>
        public Task<Dictionary<string, string>> GetImageAsync3()
        {
            Intent intent = new Intent(Intent.ActionPick);
            intent.SetDataAndType(MediaStore.Images.Media.ExternalContentUri, "image/*");
            intent.PutExtra(Intent.ExtraAllowMultiple,true);
            MainActivity.Instance.StartActivityForResult(Intent.CreateChooser(intent, "Select Picture"),
                MainActivity.PickImageId);
            MainActivity.Instance.PickImageTaskCompletionSource = new TaskCompletionSource<Dictionary<string, string>>();
            return MainActivity.Instance.PickImageTaskCompletionSource.Task;
        }
    }
}


我们只关注Intent实现的GetImageAsync3方法

首先先初始化一个Intent.ActionPick类型的Intent,选择数据我们需要使用ACTION_PICK 类型。 常见的Intent类型参考官方文档

https://developer.android.google.cn/guide/components/intents-common?hl=zh-cn

intent.SetDataAndType方法设置Intent的数据和MIME数据类型

https://developer.android.com/reference/android/content/Intent#setDataAndType(android.net.Uri, java.lang.String)

intent.PutExtra 设置可以多选 然后就可以通过MainActivity的静态实例InstanceStartActivityForResult方法启动这个intent了,我们这里通过Intent.CreateChooserIntent设置了一个标题,并传递requestCode用以区分业务。

编写演示代码

修改Index.razor文件,界面使用的是MASA Blazor

@page "/"
@using Masa.BuildingBlocks.Storage.ObjectStorage;
@using MediaPickSample.Service;

<MCard Color="#FFFFFF" Class="mx-auto rounded-3 mt-3" Elevation="0">
    <MCardText>
        <div class="d-flex" style="flex-wrap: wrap">
            @if (_phoneDictionary.Any())
            {
                @foreach (var phone in _phoneDictionary)
                {
                    <div style="position: relative; height: 90px; width: 90px;" class="mr-2 mb-2">
                        <MImage Src="@phone.Value" AspectRatio="1" Class="grey lighten-2">
                            <PlaceholderContent>
                                <MRow Class="fill-height" Align="@AlignTypes.Center" Justify="@JustifyTypes.Center">
                                    <MProgressCircular Indeterminate></MProgressCircular>
                                </MRow>
                            </PlaceholderContent>
                        </MImage>
                        <MButton Small Icon Tile Style="position: absolute; top: 0; right: 0; background: #000000; opacity: 0.5;" Dark OnClick="() => RemoveItem(phone.Key)">
                            <MIcon>
                                mdi-close
                            </MIcon>
                        </MButton>
                    </div>
                }
            }
            <MBottomSheet>
                <ActivatorContent>
                    <MButton XLarge Icon Style="background: #F7F8FA;border-radius: 2px; height:80px;width:80px; " @attributes="@context.Attrs">
                        <MIcon XLarge Color="#D8D8D8">mdi-camera</MIcon>
                    </MButton>
                </ActivatorContent>
                <ChildContent>
                    <MCard>
                        <MList>
                            <MListItem OnClick="GetImageAsync1"><MListItemContent><MListItemTitle>Maui-MediaPicker</MListItemTitle></MListItemContent></MListItem>
                            <MListItem OnClick="GetImageAsync2"><MListItemContent><MListItemTitle>Maui-FilePicker</MListItemTitle></MListItemContent></MListItem>
                            <MListItem OnClick="GetImageAsync3"><MListItemContent><MListItemTitle>Intent</MListItemTitle></MListItemContent></MListItem>
                        </MList>
                    </MCard>
                </ChildContent>
            </MBottomSheet>
        </div>
    </MCardText>
</MCard>
@code {
    [Inject]
    private IPhotoPickerService _photoPickerService { get; set; }
    [Inject]
    private IClient _client { get; set; }
    private Dictionary<string, string> _phoneDictionary { get; set; } = new Dictionary<string, string>();

    private async Task GetImageAsync1()
    {
       ...
    }
    private async Task GetImageAsync2()
    {
       ...
    }
    private async Task GetImageAsync3()
    {
        var photoDic = await _photoPickerService.GetImageAsync3();
        foreach (var photo in photoDic)
        {
            var fileUrl = await UploadImageAsync(photo.Value, Path.GetExtension(photo.Key));
            _phoneDictionary.Add(photo.Key, fileUrl);
        }
    }
    private void RemoveItem(string key)
    {
        _phoneDictionary.Remove(key);
    }

    private async Task<string> UploadImageAsync(string fileBase64, string fileExtension)
    {
        byte[] fileBytes = Convert.FromBase64String(fileBase64);
        var newFileName = $"{Guid.NewGuid() + fileExtension}";
        var newFileFullPath = $"images/xxx/xxx/{newFileName}";
        using (var fileStream = new MemoryStream(fileBytes))
        {
            try
            {
                await InvokeAsync(StateHasChanged);

                await _client.PutObjectAsync("xxx", newFileFullPath, fileStream);

                return $"https://img-cdn.xxx.cn/{newFileFullPath}";
            }
            catch (Exception ex)
            {
                if (ex.Message.Contains("x-oss-hash-crc64ecma"))
                {
                    return $"https://img-cdn.xxx.cn/{newFileFullPath}";
                }
                else
                {
                    return string.Empty;
                }
            }
        }
    }
}


代码比较简单,不过多介绍,这里的UploadImageAsync方法使用的是Masa.BuildingBlocks.Storage提供的SDK实现上传到阿里云存储。 不要忘记在MauiProgram.cs添加依赖注入

#if ANDROID
            builder.Services.AddSingleton<IPhotoPickerService, AndroidPhotoPickerService>();
#endif


AndroidManifest.xml添加必要的权限-android.permission.READ_EXTERNAL_STORAG,并添加android:usesCleartextTraffic="true"(上传阿里云使用)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
	<application android:allowBackup="true" android:icon="@mipmap/appicon" android:usesCleartextTraffic="true"  android:roundIcon="@mipmap/appicon_round" android:supportsRtl="true"></application>

	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
	<uses-permission android:name="android.permission.INTERNET" />
	<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

</manifest>


三、演示效果

在这里插入图片描述

下一篇我们介绍另外一种实现方式。


如果你对我们的 MASA Framework 感兴趣,无论是代码贡献、使用、提 Issue,欢迎联系我们

WeChat:MasaStackTechOps QQ:7424099

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