我一直在尝试在线找到多种解决方案，但尚未找到一种有效的解决方案。
我正在尝试从图库中选择图片，然后上传它。现在，我只想弄清楚如何获得图像的路径。
我首先尝试了找到here的配方，然而，总是返回null作为答案。
我现在正试图使用这个代码，我从另一个SO问题中找到了这个代码。
public static readonly int ImageId = 1000;
protected override void OnCreate (Bundle bundle)
{
base.OnCreate (bundle);
GetImage(((b, p) => {
Toast.MakeText(this, "Found path: " + p, ToastLength.Long).Show();
}));
}
public delegate void OnImageResultHandler(bool success, string imagePath);
protected OnImageResultHandler _imagePickerCallback;
public void GetImage(OnImageResultHandler callback)
{
if (callback == null) {
throw new ArgumentException ("OnImageResultHandler callback cannot be null.");
}
_imagePickerCallback = callback;
InitializeMediaPicker();
}
public void InitializeMediaPicker()
{
Intent = new Intent();
Intent.SetType("image/*");
Intent.SetAction(Intent.ActionGetContent);
StartActivityForResult(Intent.CreateChooser(Intent, "Select Picture"), 1000);
}
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
if ((requestCode != 1000) || (resultCode != Result.Ok) || (data == null)) {
return;
}
string imagePath = null;
var uri = data.Data;
try {
imagePath = GetPathToImage(uri);
} catch (Exception ex) {
// Failed for some reason.
}
_imagePickerCallback (imagePath != null, imagePath);
}
private string GetPathToImage(Android.Net.Uri uri)
{
string doc_id = "";
using (var c1 = ContentResolver.Query (uri, null, null, null, null)) {
c1.MoveToFirst ();
String document_id = c1.GetString (0);
doc_id = document_id.Substring (document_id.LastIndexOf (":") + 1);
}
string path = null;
// The projection contains the columns we want to return in our query.
string selection = Android.Provider.MediaStore.Images.Media.InterfaceConsts.Id + " =? ";
using (var cursor = ManagedQuery(Android.Provider.MediaStore.Images.Media.ExternalContentUri, null, selection, new string[] {doc_id}, null))
{
if (cursor == null) return path;
var columnIndex = cursor.GetColumnIndexOrThrow(Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data);
cursor.MoveToFirst();
path = cursor.GetString(columnIndex);
}
return path;
}
但是，路径仍为空。
如何获取所选图像的路径？
答案 0 :(得分：1)
从以下位置更改imagePath：
imagePath = GetPathToImage(uri);
要
imagePath = UriHelper.GetPathFromUri(this, data.Data);
然后将以下类添加到您的项目中：
using Android.Content;
using Android.Database;
using Android.OS;
using Android.Provider;
using DroidEnv = Android.OS.Environment;
using DroidUri = Android.Net.Uri;
namespace MyApp.Helpers
{
public static class UriHelper
{
/// <summary>
/// Method to return File path of a Gallery Image from URI.
/// </summary>
/// <param name="context">The Context.</param>
/// <param name="uri">URI to Convert from.</param>
/// <returns>The Full File Path.</returns>
public static string GetPathFromUri(Context context, DroidUri uri)
{
//check here to KITKAT or new version
// bool isKitKat = Build.VERSION.SdkInt >= Build.VERSION_CODES.Kitkat;
bool isKitKat = Build.VERSION.SdkInt >= BuildVersionCodes.Kitkat;
// DocumentProvider
if (isKitKat && DocumentsContract.IsDocumentUri(context, uri))
{
// ExternalStorageProvider
if (isExternalStorageDocument(uri))
{
string docId = DocumentsContract.GetDocumentId(uri);
string[] split = docId.Split(':');
string type = split[0];
if (type.Equals("primary", System.StringComparison.InvariantCultureIgnoreCase))
{
return DroidEnv.ExternalStorageDirectory + "/" + split[1];
}
}
// DownloadsProvider
else if (isDownloadsDocument(uri))
{
string id = DocumentsContract.GetDocumentId(uri);
DroidUri ContentUri = ContentUris.WithAppendedId(
DroidUri.Parse("content://downloads/public_downloads"), long.Parse(id));
return GetDataColumn(context, ContentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri))
{
string docId = DocumentsContract.GetDocumentId(uri);
string[] split = docId.Split(':');
string type = split[0];
DroidUri contentUri = null;
if ("image".Equals(type))
{
contentUri = MediaStore.Images.Media.ExternalContentUri;
}
else if ("video".Equals(type))
{
contentUri = MediaStore.Video.Media.ExternalContentUri;
}
else if ("audio".Equals(type))
{
contentUri = MediaStore.Audio.Media.ExternalContentUri;
}
string selection = "_id=?";
string[] selectionArgs = new string[] { split[1] };
return GetDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if (uri.Scheme.Equals("content", System.StringComparison.InvariantCultureIgnoreCase))
{
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.LastPathSegment;
return GetDataColumn(context, uri, null, null);
}
// File
else if (uri.Scheme.Equals("file", System.StringComparison.InvariantCultureIgnoreCase))
{
return uri.Path;
}
return null;
}
/// <summary>
/// Get the value of the data column for this URI. This is useful for
/// MediaStore URIs, and other file-based ContentProviders.
/// </summary>
/// <param name="context">The Context.</param>
/// <param name="uri">URI to Query</param>
/// <param name="selection">(Optional) Filter used in the Query.</param>
/// <param name="selectionArgs">(Optional) Selection Arguments used in the Query.</param>
/// <returns>The value of the _data column, which is typically a File Path.</returns>
private static string GetDataColumn(Context context, DroidUri uri, string selection, string[] selectionArgs)
{
ICursor cursor = null;
string column = "_data";
string[] projection = {
column
};
try
{
cursor = context.ContentResolver.Query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.MoveToFirst())
{
int index = cursor.GetColumnIndexOrThrow(column);
return cursor.GetString(index);
}
}
finally
{
if (cursor != null)
cursor.Close();
}
return null;
}
/// <param name="uri">The URI to Check.</param>
/// <returns>Whether the URI Authority is ExternalStorageProvider.</returns>
private static bool isExternalStorageDocument(DroidUri uri)
{
return "com.android.externalstorage.documents".Equals(uri.Authority);
}
/// <param name="uri">The URI to Check.</param>
/// <returns>Whether the URI Authority is DownloadsProvider.</returns>
private static bool isDownloadsDocument(DroidUri uri)
{
return "com.android.providers.downloads.documents".Equals(uri.Authority);
}
/// <param name="uri">The URI to Check.</param>
/// <returns>Whether the URI Authority is MediaProvider.</returns>
private static bool isMediaDocument(DroidUri uri)
{
return "com.android.providers.media.documents".Equals(uri.Authority);
}
/// <param name="uri">The URI to check.</param>
/// <returns>Whether the URI Authority is Google Photos.</returns>
private static bool isGooglePhotosUri(DroidUri uri)
{
return "com.google.android.apps.photos.content".Equals(uri.Authority);
}
}
}
这个类应该能够处理你抛出的任何Uri并返回FilePath。不要忘记将命名空间导入您的Activity！希望有所帮助。改编自here
答案 1 :(得分：-1)
像这样实现此方法'GetPathToImage'，以提取设备上图像的路径并显示。
使用以下内容将辅助方法GetPathToImage添加到您的Activity：
private string GetPathToImage(Uri uri)
{
string path = null;
// The projection contains the columns we want to return in our query.
string[] projection = new[] {Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data };
using (ICursor cursor = ManagedQuery(uri, projection, null, null, null))
{
if (cursor != null)
{
int columnIndex = cursor.GetColumnIndexOrThrow(Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data);
cursor.MoveToFirst();
path = cursor.GetString(columnIndex);
}
}
return path;
}
希望这会对你有所帮助。