我希望能够将文件保存在用户选择的文件夹中,因此我想向用户提供一个目录列表,让用户能够选择他想要导出数据的目录。不幸的是,我没有找到任何目录/文件夹选择器的示例,我只找到了一个对我没有用处的文件选择器。
https://github.com/jfversluis/FilePicker-Plugin-for-Xamarin-and-Windows
是否有适用于Xamarin.Forms的选取文件夹组件?实际上我只是在做Android,但我们使用Xamarin.forms。
https://github.com/jfversluis/FilePicker-Plugin-for-Xamarin-and-Windows
是否有适用于Xamarin.Forms的选取文件夹组件?实际上我只是在做Android,但我们使用Xamarin.forms。
我想不到任何一个。
有了netstandard,一切都更加简单,因为您可以使用经典的c#文件API来获取文件夹。
您只需要知道特殊文件夹与Android文件夹之间的映射关系(例如):
System.Environment.SpecialFolder Path
ApplicationData INTERNAL_STORAGE/.config
Desktop INTERNAL_STORAGE/Desktop
LocalApplicationData INTERNAL_STORAGE/.local/share
MyDocuments INTERNAL_STORAGE
MyMusic INTERNAL_STORAGE/Music
MyPictures INTERNAL_STORAGE/Pictures
MyVideos INTERNAL_STORAGE/Videos
Personal INTERNAL_STORAGE
来源: https://learn.microsoft.com/zh-cn/xamarin/android/platform/files/
iOS的内容相同:
https://learn.microsoft.com/zh-cn/xamarin/ios/app-fundamentals/file-system
但它真的很容易实现,只需枚举所有文件夹并在ListView中显示他们即可。
编辑:实现更多细节。
事实上,你要编写一个 "目录浏览器" 十分简单,以下是概念。
Page
中有一个 ListView
Page
中有一个 Cancel
按钮和一个 Select
按钮ViewModel
中有一个 CurrentPath
CurrentPath
绑定到你的页面的 Title
ViewModel
中有一个 List<DirectoryViewModel> Directories
每当用户点击列表中的项目时:
RaisePropertyChange(nameof(Directories))
)ListView
将相应地更新每次返回时:
如果到达根路径 " / ",则在点击返回时不执行任何操作。
哦,你可以使用这个 Grid
组件来代替 ListView
,看起来更漂亮 ;)。
https://github.com/roubachof/Sharpnado.Presentation.Forms#grid-Layout
您可以编辑此内容以使其正常工作。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Java.IO;
using Java.Util;
namespace Android.Basic.IO
{
public class DirectoryPicker : ListActivity
{
public const String START_DIR = "startDir";
public const String ONLY_DIRS = "onlyDirs";
public const String SHOW_HIDDEN = "showHidden";
public const String CHOSEN_DIRECTORY = "chosenDir";
public const int PICK_DIRECTORY = 43522;
private File dir;
private Boolean showHidden = false;
private bool onlyDirs = true;
public override void OnCreate(Bundle savedInstanceState, PersistableBundle persistentState)
{
base.OnCreate(savedInstanceState, persistentState);
Bundle extras = Intent.Extras;
dir = OS.Environment.ExternalStorageDirectory;
if (extras != null)
{
String preferredStartDir = extras.GetString(START_DIR);
showHidden = extras.GetBoolean(SHOW_HIDDEN, false);
onlyDirs = extras.GetBoolean(ONLY_DIRS, true);
if (preferredStartDir != null)
{
File startDir = new File(preferredStartDir);
if (startDir.IsDirectory)
{
dir = startDir;
}
}
}
SetContentView(Resource.Layout.folder_chooser_activity);
var title = dir.AbsolutePath.ToString();
Title = (title);
Button btnChoose = (Button)FindViewById(Resource.Id.btnChoose);
String name = dir.Name;
if (name.Length == 0)
name = "/";
btnChoose.Text = ("Choose " + "'" + name + "'");
btnChoose.Click += delegate
{
returnDir(dir.AbsolutePath);
};
ListView lv = this.ListView;
lv.TextFilterEnabled = (true);
if (!dir.CanRead())
{
Context context = ApplicationContext;
String msg = "Could not read folder contents.";
Toast.MakeText(context, msg, ToastLength.Long).Show();
return;
}
var files = filter(dir.ListFiles(), onlyDirs, showHidden);
String[] names = Names(files);
ListAdapter = (new ArrayAdapter<String>(this, Resource.Layout.folder_chooser_item, names));
lv.ItemClick += (ff, gg) =>
{
var position = gg.Position;
if (!files[gg.Position].IsDirectory)
return;
String path = files[position].AbsolutePath;
var intent = new Intent(this, typeof(DirectoryPicker));
intent.PutExtra(DirectoryPicker.START_DIR, path);
intent.PutExtra(DirectoryPicker.SHOW_HIDDEN, showHidden);
intent.PutExtra(DirectoryPicker.ONLY_DIRS, onlyDirs);
StartActivityForResult(intent, PICK_DIRECTORY);
};
}
protected void OnActivityResult(int requestCode, int resultCode, Intent data)
{
if (requestCode == PICK_DIRECTORY && resultCode == (int)Result.Ok)
{
Bundle extras = data.Extras;
String path = (String)extras.Get(DirectoryPicker.CHOSEN_DIRECTORY);
returnDir(path);
}
}
private void returnDir(String path)
{
Intent result = new Intent();
result.PutExtra(CHOSEN_DIRECTORY, path);
SetResult(Result.Ok, result);
Finish();
}
public List<File> filter(File[] file_list, bool onlyDirs, bool showHidden)
{
var files = new List<File>();
foreach (var file in file_list)
{
if (onlyDirs && !file.IsDirectory)
continue;
if (!showHidden && file.IsHidden)
continue;
files.Add(file);
}
Collections.Sort(files);
return files;
}
public String[] Names(List<File> files)
{
String[] names = new String[files.Count];
int i = 0;
foreach (var file in files)
{
names[i] = file.Name;
i++;
}
return names;
}
}
}
以结果的形式启动活动,然后在OnActivityResult中捕获
if (requestCode == DirectoryPicker.PICK_DIRECTORY && resultCode == Result.Ok)
{
Bundle extras = data.Extras;
String path = (String)extras.Get(DirectoryPicker.CHOSEN_DIRECTORY);
// do stuff with path
}