While our game may be running without any issues in the editor or even in…
Creating a File Picker
In this post we’re going to see how to create a basic File Picker inside Unreal Engine. We’re going to use the built-in tools that the engine provides and read a text file.
[button size=”big” color=”black” link=”https://github.com/orfeasel/UE4-Cpp-Tutorials/tree/master/FilePicker”]Download the entire source code from my GitHub repo[/button]Adding the required Dependencies
For this post I have created a C++ project using the 4.20 version of the engine. Then, I added the SlateCore dependency in the public module names in the <MyProject>.Build.cs file:
PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore", "HeadMountedDisplay","SlateCore" });Creating the file picker
Ideally, you will place the functionality of the file picker in a utility library so you can use it throughout your project. However I’ve added the code inside the character code just for demonstration purposes.
I have created two functions, one that is responsible for opening and displaying the file picker and one which is responsible for getting the contents of the selected file:
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/* * Opens a file dialog for the specified data. Leave FileTypes empty to be able to select any files. * Filetypes must be in the format of: <File type Description>|*.<actual extension> * You can combine multiple extensions by placing ";" between them * For example: Text Files|*.txt|Excel files|*.csv|Image Files|*.png;*.jpg;*.bmp will display 3 lines for 3 different type of files. */ UFUNCTION(BlueprintCallable, Category = "FilePicker") void OpenFileDialog(const FString& DialogTitle, const FString& DefaultPath, const FString& FileTypes, TArray<FString>& OutFileNames); /*Prints the data of the given file*/ UFUNCTION(BlueprintCallable, Category = "FilePicker") void PrintData(const FString& File); |
Before implementing the logic for each function, make sure to include the following header files in your class:
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//File picker includes #include "Developer/DesktopPlatform/Public/IDesktopPlatform.h" #include "Developer/DesktopPlatform/Public/DesktopPlatformModule.h" |
The reason we need to include them is so we can have access to the deskplatform code where the built-in file picker exists.
Here’s the implementation of each function:
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void AFilePickerCharacter::OpenFileDialog(const FString& DialogTitle, const FString& DefaultPath, const FString& FileTypes, TArray<FString>& OutFileNames) { if (GEngine) { if (GEngine->GameViewport) { void* ParentWindowHandle = GEngine->GameViewport->GetWindow()->GetNativeWindow()->GetOSWindowHandle(); IDesktopPlatform* DesktopPlatform = FDesktopPlatformModule::Get(); if (DesktopPlatform) { //Opening the file picker! uint32 SelectionFlag = 0; //A value of 0 represents single file selection while a value of 1 represents multiple file selection DesktopPlatform->OpenFileDialog(ParentWindowHandle, DialogTitle, DefaultPath, FString(""), FileTypes, SelectionFlag, OutFileNames); } } } } void AFilePickerCharacter::PrintData(const FString& File) { //Parse the data into a string array TArray<FString> LoadedText; FFileHelper::LoadFileToStringArray(LoadedText, *File); //Print the contents for (int32 i = 0; i < LoadedText.Num(); i++) { GLog->Log(LoadedText[i]); } } |
After compiling my code, I created the following BP code to read the contents of the single file I selected:
Here is how the file dialog looks from within the engine:
It’s worth noting that depending on the files that you want to read your print/parse data function may differ from this post. If you want to be able to select any data type you can leave the file types string empty.
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Do you know how to make sure that this works with a packaged product? For example, when packaging with UE4.19 for Windows 64 bit, your function gives me this error:
https://i.imgur.com/p3d2upy.png
But it works just fine in PIE!
Hey, I’ve not tested yet, but I think this is because of a missing module linkage. It’s weird that there is no compile time error actually.
I will try with
PublicDependencyModuleNames.AddRange(new string[] { “Core”, “CoreUObject”, “Engine”, “InputCore”, “DesktopPlatform” });
(SlateCore and HeadMountedDisplay are other modules, maybe useful for the author, but unnecessary for this tutorial)
I will let you know if this works
Hi, I’m having the same issue also with UE 19. Should I try a different version of ue?
Is there any chance you could compile this as a plugin? I’m not familiar with C++, so this would be a huge help. Thanks!
Hey, thank you for this it is really helpful! Right now I only have it working in PIE, do you know how I could modify this to work in the editor? Trying to build out some fool proof UI for getting different URI’s
hey, package shipping filed error,
UATHelper: Packaging (Windows（64位）): ERROR: Missing precompiled manifest for ‘DesktopPlatform’. This module was most likely not flagged for being included in a precompiled build – set ‘PrecompileForTargets = PrecompileTargetsType.Any;’ in DesktopPlatform.build.cs to override.
Can You know how to setting ? Thanks for you
Is it possible to select folder paths?, not a file.
For anyone else who reads this: look into PromptUserForDirectory. Not sure if it supports multiple filepath selection, though.
The DesktopPlatform module is a Developer module, the EULA version of the engine does not include Developer modules for Shipping builds. An Epic employee recommends building a custom UMG/Slate file picker that relies on IPlatformFile system instead.
Very useful. Just a note, rather than declaring a specific windows handle, which didn’t seem to work for me in 4.24, let Slate handle that by using this code as the first argument in the OpenFileDialogue:
FSlateApplication::Get().FindBestParentWindowHandleForDialogs(nullptr)
Daniel, thank you a million times,
I’ve been trying to get a viewport window handle in the editor for a couple hours now and your SlateApplication WindowHandle get worked like a charm. Cheers!
Thanks for the example! Successfully works on UE5!