获取图库图像 Xamarin 的路径?

Question

我正在尝试获取图库图像的路径。我正在获取存储在内部存储中的图像的路径，而不是外部存储中的路径。我还启用了已授予的读写存储和相机访问权限。 这是我的代码

void ChoosePhoto()
{
try
{
var imageIntent = new Intent();
imageIntent.SetType("image/*");
imageIntent.SetAction(Intent.ActionGetContent);
StartActivityForResult(Intent.CreateChooser(imageIntent, "Select photo"), 0);
}
catch (Exception ex)
{
throw ex;
}
} 
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
if (requestCode == CAMERA_CAPTURE)
{
// camera operation
}
else
{
Console.WriteLine("choose pic from Gallery");
var uri = data.Data;
var path = getRealPathFromURI(uri); //path returns null when i select image from external storage;
}
}
private String getRealPathFromURI(Uri contentURI)
{
string[] proj = { MediaStore.Images.ImageColumns.Data };
String result;
var cursor = ContentResolver.Query(contentURI, proj, null, null, null);
if (cursor == null)
result = contentURI.Path;
else
{
int idx= cursor.GetColumnIndex(MediaStore.Images.ImageColumns.Data);
cursor.MoveToFirst();
result = cursor.GetString(idx);
cursor.Close();
}
return result;
}

Answer 1

我想获取我从图库中选择的选定图像路径

问题是将Android.Net.Uri更改为path，这是一个解决方案：

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 = ContentResolver.Query(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;
}

当您从图库中选择图片时：

ChoosePhoto();
...
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
if (requestCode == 0)
{
var uri = data.Data;
var path = GetPathToImage(uri);
System.Diagnostics.Debug.WriteLine("Image path == " + path );
//My result is this ==> [0:] Image path == /storage/emulated/0/DCIM/Camera/IMG_20170813_223324.jpg
}
}

最重要的是，当你使用这种方法时，也许你会遇到这个问题：

Java.Lang.SecurityException： Permission Denial： 读取 com.android.providers.media.MediaProvider uri content://media/external/images/media from pid=21975， uid=10417 需要 android.permission.READ_EXTERNAL_STORAGE， 或 grantUriPermission((

当 API>= 23，运行时请求权限时，用户在应用运行时(而不是在安装应用时(向应用授予权限。您应该检查您是否具有android.permission.READ_EXTERNAL_STORAGE权限，如果没有，则需要请求权限。