[Android] Implement native file picker support

[syntaxerror247]

1. First commit, creates a new DisplayServer Flag FEATURE_NATIVE_DIALOG_FILE_EXTRA, for access to USERDATA and RESOURCES directory and OPTIONS feature. Native File Dialog will fallback to custom one if not supported.

2. Second commit, implements native file picker support for android

This Partially addresses

• Allow use of native system file picker dialog on iOS and web godot-proposals#1123

• Add support for Android native file dialogs godot-proposals#10983

Test App (arm64): Test.zip

Demo Video

VID_20241021_215329.mp4

Task List

• Every FileMode is supported (except OPEN_ANY).
• Filters are supported (MIME types).
• Current directory(initial directory) supported.
• Filename for SAVE mode supported.
• callback supported.
• Options support Not possible with system file picker.
• show hidden It can be set manually with system file picker.
• selected filter index callback Not possible with multi select, that's why omited this feature entirely.
• access mode RESOURCES and USERDATA support Not possible with native picker, will fallback to custom one.

[syntaxerror247]

Now, Current_directory (initial directory) is also supported. It should be an external storage directory, users can use OS.get_system_dir(OS.SYSTEM_DIR_DESKTOP) to get root path.
example:

func _show_native_file_picker() -> void:
	var filters = PackedStringArray(["image/*","text/plain","application/pdf"])
	var current_directory = OS.get_system_dir(OS.SYSTEM_DIR_DOCUMENTS)
	DisplayServer.file_dialog_show("title", current_directory, "filename", false, DisplayServer.FILE_DIALOG_MODE_OPEN_FILE, filters, _picker_callback)

func _picker_callback(status: bool, selected_paths: PackedStringArray, selected_filter_index: int):
	$Label.text += str("Status: ",status,"\n")
	$Label.text += str("Selected Paths: ",selected_paths,"\n\n")

[syntaxerror247]

This is now ready for review, and all features are functioning as expected in my tests.

Regarding the two unchecked tasks:

• I considered implementing the selected_filter_index callback for single file selection, but it won't be feasible for multi-select scenarios. Therefore, I decided to omit this feature entirely.
• As for supporting RESOURCES and USERDATA access modes, this is not possible with the android native file picker.

Please let me know if any additional adjustments are needed!

[bruvzg]

Since implementation is limited (which is expected for Android), limitations (no options, no usr:// and res:// access) should be mentioned in the class reference documentation for FileDialog and DisplayServer:

DisplayServer:

godot/doc/classes/DisplayServer.xml

Line 130 in 44fa552

<method name="file_dialog_show">

godot/doc/classes/DisplayServer.xml

Line 150 in 44fa552

<method name="file_dialog_with_options_show">

FileDialog:

godot/doc/classes/FileDialog.xml

Line 166 in 44fa552

<member name="use_native_dialog" type="bool" setter="set_use_native_dialog" getter="get_use_native_dialog" default="false">

godot/doc/classes/FileDialog.xml

Line 22 in 44fa552

<method name="add_option">

Also, it might be worth adding new DisplayServer feature flags for options and res/usr access, and check these flags in the FileDialog to automatically switch to embedded dialog when incompatible options are used.

[syntaxerror247]

@bruvzg how about only one new feature tag FEATURE_NATIVE_DIALOG_FILE_EXTRA ?

[bruvzg]

how about only one new feature tag FEATURE_NATIVE_DIALOG_FILE_EXTRA ?

One flag should be OK (iOS will have the same limitations).

[llama-nl]

@syntaxerror247 can I have the APK to test?

[syntaxerror247]

@UnderGamer05 I have uploaded the apk, check in PR description.

[syntaxerror247]

Hi @m4gr3d , just checking in to see if the updates I made in the PR align with what you had in mind. Let me know if there's anything else you'd like me to tweak.

[m4gr3d]

Looks good!

Added some minor comments to address.

[syntaxerror247]

Rebased and resolved conflicts.

[Repiteo]

Thanks!

[ThatSimpleDev]

@syntaxerror247 Just tested the test apk provided here and when opening the resources it doesn't open the native file picker is that intentional?
Also it says you don't have enough permissions as you can see in the screenshot below 👇

I also tested this on v4.4 Dev 5 and when I try to use the native file dialog (not through code) and setting the access as ACCESS_FILESYSTEM the app immediately closes when I press the button. I believe I have checked the needed read user directory permissions (It asked to enable the same permission as the test apk you provided). Did you do this through code?

[syntaxerror247]

Just tested the test apk provided here and when opening the resources it doesn't open the native file picker is that intentional?

@ThatSimpleDev Yes, that intentional. Android doesn't allow access to user:// and res:// directory, that's why it fallbacks to custom Filedialog.

I also tested this on v4.4 Dev 5 and when I try to use the native file dialog (not through code) and setting the access as ACCESS_FILESYSTEM the app immediately closes when I press the button.

Yes, This is a regression due an update to FileDialog. This issue wasn't present in dev4. This will be solved after these two PRs #99350 and #99385 are merged.

For now, you can use it via code.