Detecting escape key in InputText

[notnullnotvoid]

Version: 1.70 release
Operating System: macOS 10.14.5
Back-ends: SDL + opengl3

My Issue/Question:

My specific situation is this: I have a few windows which I show when performing some action, like loading or saving a level. The window has a text input, and a "Confirm" and "Cancel" button, standard dialog box stuff. I have already made it so that hitting ENTER in the text input confirms the action and closes the window, and would like to make hitting ESC cancel the action and close the window.

Is there a way to be notified (bool return, callback, etc.) when the ESC key is pressed in an InputText field? Or, is there some way to achieve similar results by different means?

Standalone, minimal, complete and verifiable example:

static bool saveAs = true;
if (saveAs) {
    ImGui::Begin("Save level as...", nullptr, ImGuiWindowFlags_AlwaysAutoResize);
    static char buffer[1024] = {};
    bool enter = ImGui::InputText("Level name", buffer, sizeof(buffer), ImGuiInputTextFlags_EnterReturnsTrue);
    bool click = ImGui::Button("Save");
    ImGui::SameLine();
    if (ImGui::Button("Cancel")) { saveAs = false; buffer[0] = '\0'; }
    if (enter || click) {
        // ... [code that saves the level] ...
        saveAs = false;
        buffer[0] = '\0';
    }
    ImGui::End();
}

[notnullnotvoid]

I was able to work around this by adding a special case to ignore io.WantCaptureKeyboard for the escape key when the window is active, and holding the result of IsItemFocused() from the previous frame (because it will already be unfocused on the frame when ESC is pressed), like so:

bool escPressedThisFrame = ...; //set in SDL event loop when (event.type == SDL_KEYDOWN && event.key.keysym.scancode == SDL_SCANCODE_ESCAPE)

static bool saveAs = true;
if (saveAs) {
    static bool focusedLastFrame = false;
    ImGui::Begin("Save level as...", nullptr, ImGuiWindowFlags_AlwaysAutoResize);
    static char buffer[1024] = {};
    bool enter = ImGui::InputText("Level name", buffer, sizeof(buffer), ImGuiInputTextFlags_EnterReturnsTrue);
    if (focusedLastFrame && escPressedThisFrame) { saveAs = false; buffer[0] = '\0' };
    focusedLastFrame = ImGui::IsItemFocused();
    bool click = ImGui::Button("Save");
    ImGui::SameLine();
    if (ImGui::Button("Cancel")) { saveAs = false; buffer[0] = '\0'; }
    if (enter || click) {
        // ... [code that saves the level] ...
        saveAs = false;
        buffer[0] = '\0';
    }
    ImGui::End();
}

Maybe this solution is good enough.

[ocornut]

If you enable keyboard navigation Esc wlill already close popups.

You may also look at the ImGui::IsItemDeactivated functions. Maybe test for this and IsKeyPressedMap(ImGuiKey_Escape) as a workaround in the meanwhile.

So more like:

ImGui::InputText(...)
if (ImGui::IsItemDeactivated() && ImGui::IsKeyPressed(ImGui::GetKeyIndex(ImGuiKey_Escape))
    // do stuff

If you want Escape to close the popup while an InputText is active (in a single press, rather that the generic 2 presses, one to make inputtext inactive, one to close the popup, it is more of a Nav problem, I don't have a proper solution for it right now.

[codecat]

Would it make sense to have a special callback for cancelling input? Similar to how autocompletion or history navigation is set up. In my opinion this would be a better solution than explicitly checking for the key with ImGui::IsKeyPressed.

It looks like the code to do this cleanly is already set up for this, as it would only have to set EventKey in the callback data to ImGuiKey_Escape. This could be something like ImGuiInputTextFlags_CallbackCancel.

[ocornut]

Three things:

One: I recently added ImGuiInputTextFlags_EscapeClearsAll (#5688) since this was clearly a common case many wanted.

Two: In a regular active InputText within a popup, without ImGuiInputTextFlags_EscapeClearsAll:

• 1st press of Escape: cancel edit, deactivate input
• 2nd press of Escape: close popup

vs With ImGuiInputTextFlags_EscapeClearsAll:

• 1st press of Escape: clear text (if any)
• 2nd press of Escape: deactivate input
• 3rd press of Escape: close popup

Three: When not inside a Popup you need to program the window/modal closure yourself.
This is now possible thanks to the new input owner system I just committed.

e.g. for a modal:

#include "imgui_internal.h" // new input owner feature are internal until we expose in 1.90?
[...]
ImGui::InputText("buf", buf, 64, ImGuiInputTextFlags_EscapeClearsAll);
if (ImGui::IsKeyPressed(ImGuiKey_Escape, ImGuiKeyOwner_None))
    ImGui::CloseCurrentPopup();

Note the ImGuiKeyOwner_None parameter: it will check that the Escape key is not owned by the InputText().
The default value for that owner is 0 == ImGuiKeyOwner_Any which means "don't test for owner" (legacy behavior).