[1.12.2] "Stacking" GUIs on top of each other?

[Kinniken]

Hi all,

 

I have two GUIs, one that extends GuiContainer to handle trade in my mod, and one with some user help that extends GuiScreen directly. There's a help button on the trade one that opens the other one, using Minecraft.getMinecraft().displayGuiScreen().

 

It works fine, except that opening the help closes the other one. I'd prefer it if the player was taken back to the other one instead. Is this possible "natively", or do I need to do it manually by reopening the first GUI with whatever context it had?

 

Thanks

[diesieben07]

You have to manually pass in a "previous" GuiScreen into the stacked screen.

[Kinniken]

I can reuse the same GuiScreen object? Convenient, cool.

 

Is there any callback for when a GUI is closed? I can't seem to find any at least for when the GUI is closed by using the escape key. The only solution I can see would be to override keyTyped() and reopen the older gui if I detect that the key pressed was escape, but that feels very hacky...

[desht]

2 minutes ago, Kinniken said:

I can reuse the same GuiScreen object? Convenient, cool.

 

Is there any callback for when a GUI is closed? I can't seem to find any at least for when the GUI is closed by using the escape key. The only solution I can see would be to override keyTyped() and reopen the older gui if I detect that the key pressed was escape, but that feels very hacky...

GuiScreen#onGuiClosed() is probably what you want here.  It's actually called whenever the current GUI object (if already non-null) changes, which is generally by Minecraft#displayGuiScreen() - note that a change from non-null to null also counts here.

 

So when you create your sub-GUI, store a reference to Minecraft.currentScreen in your sub-GUI constructor, and in your sub-GUI's onGuiClosed() override, call Minecraft#displayGuiScreen(parentGuiReference) to redisplay the parent GUI.  Note that you're not actually reusing the GuiScreen object - the sub-GUI is a separate object which exists at the same time as the parent GUI.

 

If you need to pass data from the sub-GUI back to the parent GUI, store a reference to the sub-GUI in the parent when you create it (most likely in actionPerformed() when the player clicks a button).  The parent's initGui() method should check for a non-null sub-GUI field and use that to extract any data that was entered by the player.  The important point being that the parent GUI object still exists while the sub-GUI is being shown (because the sub-GUI holds a reference to it), so you're redisplaying an existing GUI object, not a new one.  And the sub-GUI object still exists after it's closed (at least until the parent closes), because the parent GUI holds a reference to it.

 

[Kinniken]

onGuiClosed() looked like what I wanted... except that it's called from within displayGuiScreen() before the new GUI is set, so if I call displayGuiScreen() from within it my resetting of currentScreen gets overiden by the parent call.

 

I don"t like the solution much but I went with putting my code in an overriden keyTyped(), that works fine.

 

Thanks for the help.

[Kinniken]

Oh and on this:

"Note that you're not actually reusing the GuiScreen object - the sub-GUI is a separate object which exists at the same time as the parent GUI." 

 

Sorry, I wasn't clear, I meant that I'm reusing the GuiScreen object from my original parent screen display to display it again once the second screen is closed. Between the parent screen and the child one it's not possible of course, they are not even instances of the same class in my case.

[desht]

5 minutes ago, Kinniken said:

onGuiClosed() looked like what I wanted... except that it's called from within displayGuiScreen() before the new GUI is set, so if I call displayGuiScreen() from within it my resetting of currentScreen gets overiden by the parent call.

 

I don"t like the solution much but I went with putting my code in an overriden keyTyped(), that works fine.

 

Thanks for the help.

Actually, looking at the GUI code from PneumaticCraft, that's what we're doing too   You're right that it's not very elegant, but it does work.

 

4 minutes ago, Kinniken said:

 

Sorry, I wasn't clear, I meant that I'm reusing the GuiScreen object from my original parent screen display to display it again once the second screen is closed. Between the parent screen and the child one it's not possible of course, they are not even instances of the same class in my case.

Right, yes - that's perfectly OK to do.  You can keep a GUI object around for a while by holding a reference to it even though it's not the current GUI.

Edited November 1, 2018 by desht

[Kinniken]

Indeed, and in my case at least it saves a lot of time, since I have multiple GUIs than can be the parent and they tend to have quite a bit of contextual data. Storing all that to recreate them once the child Gui is closed would have been a pain.