Here is the code I've currently been working with:

 

package com.limforg.gui;

import java.io.IOException;

import net.minecraft.client.gui.GuiButton;
import net.minecraft.client.gui.GuiMainMenu;
import net.minecraft.client.gui.GuiScreen;
import net.minecraft.client.resources.I18n;
import net.minecraftforge.fml.client.config.GuiButtonExt;

public class MainMenu extends GuiMainMenu {
    
    
    public GuiButtonExt play;
    
    @Override
    public void initGui() {
        play = new GuiButtonExt(0, width / 2 - 75, height / 2 - 70, "play");
        buttonList.add(play);
    }
    
    @Override
    protected void mouseClicked(int mouseX, int mouseY, int mouseButton) throws IOException {
        super.mouseClicked(mouseX, mouseY, mouseButton);
    }
    
    @Override
    public void drawScreen(int mouseX, int mouseY, float partialTicks) {
        drawDefaultBackground();
        
        super.drawScreen(mouseX, mouseY, partialTicks);
    }
    
    @Override
    protected void actionPerformed(GuiButton button) throws IOException {
        if (button == play) {
            mc.displayGuiScreen(new GuiMainMenu());
        }
    }
}

 

 

But after launch, minecraft crashes with a stacktrace: com.limforg.gui.MainMenu.drawScreen(MainMenu.java:31)

Someone help me pls!

 

Version of minecraft 1.9

I solved this problem. I replaced "public class MainMenu extends GuiMainMenu {" to "public class MainMenu extends GuiScreen {"