davidortinau/maui-skills/maui-file-handling

// ❌ Breaks on Android — FullPath may be a content:// URI
var result = await FilePicker.Default.PickAsync();
var bytes = File.ReadAllBytes(result.FullPath);
 
// ✅ Works on all platforms
var result = await FilePicker.Default.PickAsync();
if (result is not null)
{
    using var stream = await result.OpenReadAsync();
    // process stream
}

// ❌ Using file extensions for Android — picker shows nothing
{ DevicePlatform.Android, new[] { ".json", ".txt" } }
 
// ✅ Correct MIME types for Android
{ DevicePlatform.Android, new[] { "application/json", "text/plain" } }

// ❌ Trying to write to a bundled file
var path = "data.json"; // inside Resources/Raw
File.WriteAllText(path, newContent); // fails
 
// ✅ Copy to AppDataDirectory first, then modify
string targetPath = Path.Combine(FileSystem.Current.AppDataDirectory, "data.json");
if (!File.Exists(targetPath))
{
    using var source = await FileSystem.Current.OpenAppPackageFileAsync("data.json");
    using var dest = File.Create(targetPath);
    await source.CopyToAsync(dest);
}
// Now safe to read/write targetPath

// ❌ Hard-coded path — breaks after clean rebuild
var path = "/var/mobile/.../Documents/data.json";
 
// ✅ Always use the FileSystem helper
var path = Path.Combine(FileSystem.Current.AppDataDirectory, "data.json");

// ❌ Throws on Android
using var stream = await FileSystem.Current.OpenAppPackageFileAsync("data.json");
var size = stream.Length; // NotSupportedException
 
// ✅ Copy first if you need the length
using var stream = await FileSystem.Current.OpenAppPackageFileAsync("data.json");
using var ms = new MemoryStream();
await stream.CopyToAsync(ms);
var size = ms.Length;

// ❌ NullReferenceException when user cancels
var result = await FilePicker.Default.PickAsync();
using var stream = await result.OpenReadAsync();
 
// ✅ Always null-check
var result = await FilePicker.Default.PickAsync();
if (result is null) return;
using var stream = await result.OpenReadAsync();