Detect when Combo() opened about imgui HOT 8 CLOSED

How can I detect when a Combo() is opened?

It's also worth explaining why you need this, as this might be a XY Problem question.

I need this since im using the Combo to choose a file in a folder and I want to update the list when the Combo is opened.

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If you can rework your call to Combo() to a BeginCombo() / EndCombo() pair, the combo is open if BeginCombo() returns true. You would then have to submit your items yourself, but you can look at the Combo() implementation for how to do that.

If you want to keep using the more compact Combo() function, you can calculate the popup id with ImHashStr("##ComboPopup", 0, GetItemID()) and check if that popup is currently open.

from imgui.

How can I detect when a Combo() is opened?

It's also worth explaining why you need this, as this might be a XY Problem question.

from imgui.

If you can rework your call to Combo() to a BeginCombo() / EndCombo() pair, the combo is open if BeginCombo() returns true. You would then have to submit your items yourself, but you can look at the Combo() implementation for how to do that.

If you want to keep using the more compact Combo() function, you can calculate the popup id with ImHashStr("##ComboPopup", 0, GetItemID()) and check if that popup is currently open.

Can you give me an example?

from imgui.

I need this since im using the Combo to choose a file in a folder and I want to update the list when the Combo is opened.

Then you should use if (ImGui::IsWindowAppearing())

from imgui.

Can you give me an example?

As I said, you can look at the implementation of Combo() for an example of how to use those functions. After all, that is just a wrapper for the step by step approach. Here is the exact place:
https://github.com/ocornut/imgui/blob/master/imgui_widgets.cpp#L1951-L1978

As Omar hinted at, you can use IsWindowAppearing() to test if a window has just been opened. Right after BeginCombo() returns true is the best place for that, then you are testing if the opened popup is just appearing.

from imgui.

I need this since im using the Combo to choose a file in a folder and I want to update the list when the Combo is opened.

Then you should use if (ImGui::IsWindowAppearing())

Doesnt it need a parameter? Or where should I put it? Before or after the Combo is created

from imgui.

Can you give me an example?

As I said, you can look at the implementation of Combo() for an example of how to use those functions. After all, that is just a wrapper for the step by step approach. Here is the exact place: https://github.com/ocornut/imgui/blob/master/imgui_widgets.cpp#L1951-L1978

As Omar hinted at, you can use IsWindowAppearing() to test if a window has just been opened. Right after BeginCombo() returns true is the best place for that, then you are testing if the opened popup is just appearing.

Alr thanks, I will try this

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