Xamarin 表单无法获取文件位置

Xamarin forms Unable to unable to to get file location

我必须打开相机拍照,但无法正常工作。我搜索了类似的帖子,但我无法弄清楚。有什么建议吗?

清单

<provider android:name="android.support.v4.content.FileProvider" 
              android:authorities="${applicationId}.fileprovider" 
              android:exported="false" 
              android:grantUriPermissions="true">

      <meta-data android:name="android.support.FILE_PROVIDER_PATHS" 
                 android:resource="@xml/file_paths"></meta-data>
    </provider>

file_paths

<external-files-path name="my_images" path="Pictures" />
<external-files-path name="my_movies" path="Movies" />
<external-path name="my_images" path="Android/data/com.plugin.mediatest/files/Pictures" />

代码

await CrossMedia.Current.Initialize();
            if (!CrossMedia.Current.IsTakePhotoSupported && !CrossMedia.Current.IsPickPhotoSupported)
            {
                await DisplayAlert("Message", "Unavailable", "OK");
                return;
            }
            else
            {
                var file = await CrossMedia.Current.TakePhotoAsync(new StoreCameraMediaOptions
                {
                    Directory = "Images",
                    Name = DateTime.Now +".jpg",
                    SaveToAlbum = false
                });
                await DisplayAlert("FilePath", file.Path, "OK");
                PhotoImage.Source = ImageSource.FromStream(() =>
                {
                    var stream = file.GetStream();
                    return stream;
                });

你可以在GitHub上参考这篇Usage , and there is a sample

takePhoto.Clicked += async (sender, args) =>
{
    await CrossMedia.Current.Initialize();

    if (!CrossMedia.Current.IsCameraAvailable || !CrossMedia.Current.IsTakePhotoSupported)
    {
        DisplayAlert("No Camera", ":( No camera available.", "OK");
        return;
    }

    var file = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions
    {
        Directory = "Sample",
        Name = "test.jpg"
    });

    if (file == null)
        return;

    await DisplayAlert("File Location", file.Path, "OK");

    image.Source = ImageSource.FromStream(() =>
    {
        var stream = file.GetStream();
        return stream;
    }); 
};

关于 Android Misc Setup ,

默认情况下,该库将 android.hardware.cameraandroid.hardware.camera.autofocus 作为可选功能添加到您的应用清单中。您有责任在使用前检查您的设备是否支持该硬件。相反,如果您希望 Google Play 过滤掉没有所需硬件的设备,请将以下内容添加到 Android 项目的 AssemblyInfo.cs 文件中:

[assembly: UsesFeature("android.hardware.camera", Required = true)]
[assembly: UsesFeature("android.hardware.camera.autofocus", Required = true)]

您还必须添加一些额外的配置文件以遵守新的严格模式:

1.) 将以下内容添加到您的 AndroidManifest.xml 标签内:

<provider android:name="android.support.v4.content.FileProvider" 
          android:authorities="${applicationId}.fileprovider" 
          android:exported="false" 
          android:grantUriPermissions="true">

      <meta-data android:name="android.support.FILE_PROVIDER_PATHS" 
                     android:resource="@xml/file_paths"></meta-data>
</provider>

2.) 添加一个名为 xml 的新文件夹到您的 Resources 文件夹中,并添加一个名为 file_paths.xml 的新 XML 文件。确保此 XML 文件的构建操作为:AndroidResource.

添加以下代码:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-files-path name="my_images" path="Pictures" />
    <external-files-path name="my_movies" path="Movies" />
</paths>

最终效果:

==================================更新======== ===========================

检查共享示例后,有两个问题。

首先,你最好把Solution的Nuget Package(Xamarin Forms 3.1)更新到最新版本(Xamarin Forms 4.3).

其次 , 你忘记添加 Provider 到 AndroidManifest.xml :

<provider android:name="android.support.v4.content.FileProvider" android:authorities="com.companyname.fileprovider.fileprovider" android:exported="false" android:grantUriPermissions="true">
        <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/files_paths"></meta-data>
 </provider>

注意:provider里面的部分参数(android:resource)需要修改成你在项目中自定义的名字(@xml/files_paths)。你命名它不是 @xml/file_paths ,那么它找不到提供者 .

示例效果: