[SOLVED][1.13.2]I wanted to create a GUI Button but it gave me the null pointer error

[yuckyh]

@Override
protected void initGui() {
    this.buttons.clear();
    this.buttons.add(this.buttonOk = new GuiButton(0, this.width / 2, this.height - buttonOk.height / 2,"Ok")
    {
        @Override
        public void onClick(double p_194829_1_, double p_194829_3_) {
            super.onClick(p_194829_1_, p_194829_3_);
        }
    });
    super.initGui();
}

This code is in my custom Gui which is a subclass of GuiScreen

 

This error happens when I entered my world

Spoiler

[20:28:40.340] [Server thread/INFO] [minecraft/MinecraftServer]: Test joined the game
[20:28:40.606] [Server thread/ERROR] [minecraft/MinecraftServer]: Encountered an unexpected exception
net.minecraft.crash.ReportedException: Ticking memory connection
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:140) ~[?:?]
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:769) ~[?:?]
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:669) ~[?:?]
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:115) ~[?:?]
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:565) [?:?]
    at java.lang.Thread.run(Thread.java:748) [?:1.8.0_202]
Caused by: java.lang.NullPointerException
    at com.yuckyh.equisora.client.gui.GuiClassSelect.initGui(GuiClassSelect.java:28) ~[classes/:?]
    at net.minecraft.client.gui.GuiScreen.setWorldAndResolution(GuiScreen.java:310) ~[forge-1.13.2-25.0.76_mapped_snapshot_20180921-1.13.jar:?]
    at net.minecraft.client.Minecraft.displayGuiScreen(Minecraft.java:707) ~[forge-1.13.2-25.0.76_mapped_snapshot_20180921-1.13.jar:?]
    at com.yuckyh.equisora.event.PlayerEventHandlers.onPlayerLoggedin(PlayerEventHandlers.java:18) ~[classes/:?]
    at net.minecraftforge.eventbus.ASMEventHandler_1_PlayerEventHandlers_onPlayerLoggedin_PlayerLoggedInEvent.invoke(.dynamic) ~[?:?]
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-0.8.0-service.jar:?]
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:257) ~[eventbus-0.8.0-service.jar:?]
    at net.minecraftforge.fml.hooks.BasicEventHooks.firePlayerLoggedIn(BasicEventHooks.java:54) ~[?:?]
    at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:190) ~[?:?]
    at net.minecraft.network.NetHandlerLoginServer.tryAcceptPlayer(NetHandlerLoginServer.java:113) ~[?:?]
    at net.minecraft.network.NetHandlerLoginServer.tick(NetHandlerLoginServer.java:64) ~[?:?]
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:233) ~[?:?]
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:134) ~[?:?]
    ... 5 more
[20:28:42.293] [Server thread/ERROR] [minecraft/MinecraftServer]: This crash report has been saved to: C:\Users\Admin\Desktop\Forge Mod\Equisora\run\.\crash-reports\crash-2019-03-12_20.28.40-server.txt
[20:28:42.299] [Server thread/INFO] [minecraft/MinecraftServer]: Stopping server
[20:28:42.300] [Server thread/INFO] [minecraft/MinecraftServer]: Saving players
[20:28:44.505] [Server thread/INFO] [minecraft/NetHandlerPlayServer]: Test lost connection: Internal Exception: java.lang.StackOverflowError
[20:28:44.506] [Server thread/INFO] [minecraft/MinecraftServer]: Test left the game
[20:28:44.533] [Server thread/INFO] [minecraft/NetHandlerPlayServer]: Stopping singleplayer server as player logged out
[20:28:44.570] [Server thread/INFO] [minecraft/MinecraftServer]: Saving worlds
[20:28:44.570] [Server thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'New World'/minecraft:overworld
[20:28:44.629] [Server thread/DEBUG] [ne.mi.fm.FMLWorldPersistenceHook/WP]: Gathering id map for writing to world save New World
---- Minecraft Crash Report ----
// I let you down. Sorry

Time: 3/12/19 8:28 PM
Description: Ticking memory connection

java.lang.NullPointerException: Ticking memory connection
    at com.yuckyh.equisora.client.gui.GuiClassSelect.initGui(GuiClassSelect.java:28)
    at net.minecraft.client.gui.GuiScreen.setWorldAndResolution(GuiScreen.java:310)
    at net.minecraft.client.Minecraft.displayGuiScreen(Minecraft.java:707)
    at com.yuckyh.equisora.event.PlayerEventHandlers.onPlayerLoggedin(PlayerEventHandlers.java:18)
    at net.minecraftforge.eventbus.ASMEventHandler_1_PlayerEventHandlers_onPlayerLoggedin_PlayerLoggedInEvent.invoke(.dynamic)
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80)
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:257)
    at net.minecraftforge.fml.hooks.BasicEventHooks.firePlayerLoggedIn(BasicEventHooks.java:54)
    at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:190)
    at net.minecraft.network.NetHandlerLoginServer.tryAcceptPlayer(NetHandlerLoginServer.java:113)
    at net.minecraft.network.NetHandlerLoginServer.tick(NetHandlerLoginServer.java:64)
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:233)
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:134)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:769)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:669)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:115)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:565)
    at java.lang.Thread.run(Thread.java:748)

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Client thread
Stacktrace:
    at com.yuckyh.equisora.client.gui.GuiClassSelect.initGui(GuiClassSelect.java:28)
    at net.minecraft.client.gui.GuiScreen.setWorldAndResolution(GuiScreen.java:310)
    at net.minecraft.client.Minecraft.displayGuiScreen(Minecraft.java:707)
    at com.yuckyh.equisora.event.PlayerEventHandlers.onPlayerLoggedin(PlayerEventHandlers.java:18)
    at net.minecraftforge.eventbus.ASMEventHandler_1_PlayerEventHandlers_onPlayerLoggedin_PlayerLoggedInEvent.invoke(.dynamic)
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80)
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:257)
    at net.minecraftforge.fml.hooks.BasicEventHooks.firePlayerLoggedIn(BasicEventHooks.java:54)
    at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:190)
    at net.minecraft.network.NetHandlerLoginServer.tryAcceptPlayer(NetHandlerLoginServer.java:113)
    at net.minecraft.network.NetHandlerLoginServer.tick(NetHandlerLoginServer.java:64)
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:233)

-- Ticking connection --
Details:
    Connection: net.minecraft.network.NetworkManager@25f1315b
Stacktrace:
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:134)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:769)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:669)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:115)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:565)
    at java.lang.Thread.run(Thread.java:748)

-- System Details --
Details:
    Minecraft Version: 1.13.2
    Operating System: Windows 10 (amd64) version 10.0
    Java Version: 1.8.0_202, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 234799752 bytes (223 MB) / 600309760 bytes (572 MB) up to 934281216 bytes (891 MB)
    JVM Flags: 1 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump
    FML: New FML!
    Loaded coremods (and transformers): Nothing
    Profiler Position: N/A (disabled)
    Player Count: 1 / 8; [EntityPlayerMP['Test'/82, l='New World', x=-136.50, y=74.00, z=-119.50]]
    Data Packs: vanilla, mod:forge, mod:equisora
    Type: Integrated Server (map_client.txt)
    Is Modded: Definitely; Client brand changed to 'forge'
#@!@# Game crashed! Crash report saved to: #@!@# .\crash-reports\crash-2019-03-12_20.28.40-server.txt
[20:28:45.377] [Client Shutdown Thread/INFO] [minecraft/MinecraftServer]: Stopping server
[20:28:45.379] [Client Shutdown Thread/INFO] [minecraft/MinecraftServer]: Saving players
[20:28:45.379] [Client Shutdown Thread/INFO] [minecraft/MinecraftServer]: Saving worlds
[20:28:45.380] [Client Shutdown Thread/INFO] [minecraft/MinecraftServer]: Saving chunks for level 'New World'/minecraft:overworld
[20:28:45.380] [Thread-4/FATAL] [ne.mi.fm.pa.ModFileResourcePack/]: Failed to clean up tempdir C:\Users\Admin\AppData\Local\Temp\modpacktmp8290204505741227786
[20:28:45.381] [Client Shutdown Thread/DEBUG] [ne.mi.fm.FMLWorldPersistenceHook/WP]: Gathering id map for writing to world save New World
AL lib: (EE) alc_cleanup: 1 device not closed

Process finished with exit code -1

I was wondering why declaring a new GuiButton instance give me a null pointer error

Edited March 17, 2019 by yuckyh
Putting bunch of code/log to a spoiler to improve readibility

[DavidM]

1. Use the spoiler to post big bunch of code/log.

2. 

5 minutes ago, yuckyh said:

at com.yuckyh.equisora.client.gui.GuiClassSelect.initGui(GuiClassSelect.java:28) ~[classes/:?]

Something at line 28 is null. Figure it out.

 

Hint:

Spoiler

You’ve never instantiated the button.

 

Edited March 12, 2019 by DavidM

[yuckyh]

Spoiler

package com.yuckyh.equisora.client.gui;

import net.minecraft.client.gui.GuiButton;
import net.minecraft.client.gui.GuiScreen;

public class GuiClassSelect extends GuiScreen
{
    private int guiWidth = 800;
    private int guiHeight = 450;
    private int guiCenterX = (this.width/2) - guiWidth/2;
    private int guiCenterY = (this.height/2) - guiHeight/2;

    @Override
    public void render(int mouseX, int mouseY, float partialTicks)
    {
        drawDefaultBackground();
        super.render(mouseX, mouseY, partialTicks);
    }

    @Override
    protected void initGui() {
        GuiButton buttonOk = new GuiButton(0, this.width / 2 - width, this.height*5/6,"Ok")
        {
            @Override
            public void onClick(double p_194829_1_, double p_194829_3_) {
                super.onClick(p_194829_1_, p_194829_3_);
            }
        };
        this.buttons.add(buttonOk);
        super.initGui();
    }

    @Override
    public boolean doesGuiPauseGame() {
        return true;
    }
}

My Gui class

 

The null pointer exception is gone, but my button never appeared in the gui screen

[yuckyh]

On 3/12/2019 at 10:12 PM, diesieben07 said:

You must first call super.initGui before adding your buttons.

package com.yuckyh.equisora.client.gui;

import net.minecraft.client.gui.GuiButton;
import net.minecraft.client.gui.GuiScreen;

public class GuiClassSelect extends GuiScreen
{
    private int guiWidth = 800;
    private int guiHeight = 450;
    private int guiCenterX = (this.width/2) - guiWidth/2;
    private int guiCenterY = (this.height/2) - guiHeight/2;

    @Override
    public void render(int mouseX, int mouseY, float partialTicks)
    {
        super.render(mouseX, mouseY, partialTicks);
    }

    @Override
    protected void initGui() {
        super.initGui();
        GuiButton buttonOk = new GuiButton(0, this.width / 2 - width, this.height * 5 / 6, "Ok") {
            @Override
            public void onClick(double p_194829_1_, double p_194829_3_) {
                super.onClick(p_194829_1_, p_194829_3_);
            }
        };
        this.buttons.add(buttonOk);
    }

    @Override
    public boolean doesGuiPauseGame() {
        return true;
    }
}

Is it like that? if it is, it didn't work

[yuckyh]

The GuiButton didn't appear as well

[yuckyh]

On 3/14/2019 at 4:36 PM, diesieben07 said:

This is always a negative number, so the button is off-screen.

Thank you very much! @diesieben07