I'm sure this is probably just an issue with not implementing the code correctly but I can't find any documentation that says exactly how I should do that.

 

GuiTextureButton.java:

public class GuiTextureButton extends GuiButton{

	private String location;
	
	public GuiTextureButton(int buttonId, int x, int y, int width, int height, String location) {
		super(buttonId, x, y, width, height, "");
        this.width = width;
        this.height = height;
        this.enabled = true;
        this.visible = true;
        this.id = buttonId;
        this.x = x;
        this.y = y;
        this.displayString = "";
        this.location = location;
	}

	public void drawScreen(Minecraft mc, int mouseX, int mouseY)
    {
        if (this.visible)
        {
            FontRenderer fontrenderer = mc.fontRenderer;
            mc.getTextureManager().bindTexture(new ResourceLocation(location));
            GlStateManager.color(1.0F, 1.0F, 1.0F, 1.0F);
            this.hovered = mouseX >= this.x && mouseY >= this.y && mouseX < this.x + this.width && mouseY < this.y + this.height;
            int k = this.getHoverState(this.hovered);
            GlStateManager.enableBlend();
            GlStateManager.tryBlendFuncSeparate(770, 771, 1, 0);
            GlStateManager.blendFunc(770, 771);
            this.drawTexturedModalRect(this.x, this.y, 0, 46 + k * 20, this.width / 2, this.height);
            this.drawTexturedModalRect(this.x + this.width / 2, this.y, 200 - this.width / 2, 46 + k * 20, this.width / 2, this.height);
            this.mouseDragged(mc, mouseX, mouseY);
            int l = 14737632;

            if (packedFGColour != 0)
            {
                l = packedFGColour;
            }
            else if (!this.enabled)
            {
                l = 10526880;
            }
            else if (this.hovered)
            {
                l = 16777120;
            }

            this.drawCenteredString(fontrenderer, this.displayString, this.x + this.width / 2, this.y + (this.height / 2), l);
            System.out.println("Drew button");
        }
    }
}

GuiStandMenuButton.java

public class GuiStandMenuButton {
	
	public GuiTextureButton standMenuButton;
	
	@SubscribeEvent
	public void addStandMenuButtonToInventory(GuiScreenEvent.KeyboardInputEvent.Pre event){
		if (Minecraft.getMinecraft().currentScreen instanceof GuiInventory){
			standMenuButton = new GuiTextureButton(0, 50, 50, 50, 50, "stevesbizarrecraft:textures/items/standarrow.png");
			standMenuButton.drawScreen(Minecraft.getMinecraft(), 100, 100);
		}
	}
}

 

That's not the way I would typically go about drawing a button. Normally you create an actual GUI class and add the button to that, then you open the GUI when you want it. 

 

Also, the draw screen executes every frame so by calling it in the keyboard input event I'm pretty sure it will simply flicker and go away.

I got it to show up by changing the event it fired on, but the texture won't display properly.

GuiTextureButton's drawButton method:

@Override
	public void drawButton(Minecraft mc, int mouseX, int mouseY, float partialTicks)
    {
        if (this.visible)
        {
            FontRenderer fontrenderer = mc.fontRenderer;
            mc.getTextureManager().bindTexture(new ResourceLocation(location));
            
            ScaledResolution res = new ScaledResolution(mc);
			int width = res.getScaledWidth();
			int height = res.getScaledHeight();
			
            GlStateManager.color(1.0F, 1.0F, 1.0F, 1.0F);
            this.hovered = mouseX >= this.x && mouseY >= this.y && mouseX < this.x + this.width && mouseY < this.y + this.height;
            int k = this.getHoverState(this.hovered);
            GlStateManager.enableBlend();
            GlStateManager.tryBlendFuncSeparate(770, 771, 1, 0);
            GlStateManager.blendFunc(770, 771);
    
            this.drawTexturedModalRect(this.x, this.y, 0, 46 + k * 20, 16, 16);
            this.drawTexturedModalRect(this.x + 16 / 2, this.y, width - 16 / 2, 46 + k * 20, 16, 16);
            this.mouseDragged(mc, mouseX, mouseY);
            int l = 14737632;

            if (packedFGColour != 0)
            {
                l = packedFGColour;
            }
            else if (!this.enabled)
            {
                l = 10526880;
            }
            else if (this.hovered)
            {
                l = 16777120;
            }

            this.drawCenteredString(fontrenderer, this.displayString, this.x + this.width / 2, this.y + (this.height / 2), l);
        }
    }

What it's supposed to show up as:

What it shows up as:

In addition, whenever I change it to fullscreen mode, the button seems to disappear entirely:

I feel as if some of these questions have been addressed before by others but I couldn't find anything specifically solving them.

What do the "u" and "v" parameters for that function do? I can't find any documentation that suggests what either of them are.