why is this giving me Null exemptons??

King Nothing · Dec 23rd 2017

Java

public void PlayerInventoryToChestEvent(PlayerInventoryToChestEvent event){
            Player player = event.getPlayer();
    final int infoId = event.getChestID();
    String Pname = player.getName();       
    Chest chest = getWorld().getChest(infoId);
         //Item item = chest.getItem(1);
         Item item = event.getItem();
       if (item.getName().equals("bandage")){
                                     player.sendTextMessage("yes");


       }

             else if (item !=null){
                   player.sendTextMessage("no");
                  return;
              }

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java.lang.NullPointerException
at BootyBay.PlayerInventoryToChestEvent(BootyBay.java:10)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at pluginapi.PluginEventHandler.triggerEvent(SourceFile:201)
at aU.f.a(SourceFile:883)
at aU.f.messageReceived(SourceFile:119)
at k.e.a(SourceFile:109)
at k.c.run(SourceFile:65)

why does reurn a NULL exeption?

Minotorious · Dec 23rd 2017

Which one is line number 10 in your code?

King Nothing · Dec 23rd 2017

whoops thought i edieted it correctly....

(261)(10) if (item.getName().equals("bandage")){
player.sendTextMessage("yes");

}

noci · Dec 23rd 2017

maybe because of the return in a void in line 15.
try without.

Quote from Minotorious

Which one is line number 10 in your code?

need the whole code of "BootyBay.java"

King Nothing · Dec 23rd 2017

Java

public void PlayerInventoryToChestEvent(PlayerInventoryToChestEvent event){
            Player player = event.getPlayer();
    final int infoId = event.getChestID();
    String Pname = player.getName();       
    Chest chest = getWorld().getChest(infoId);
         Item item = chest.getItem(1);
         //Item item = event.getItem();
       if (item.getName().equals("bandage")){
                                     player.sendTextMessage("yes");


       }
              // player.sendTextMessage(""+Invent[i]);
             else if (item !=null){
                   player.sendTextMessage("no");
                  return;
              }
            player.sendTextMessage("[#ffff00] chest id: " + chest.getID());
            if (infoId == 0){


                 chest.clear();
   String query = "SELECT * FROM Money WHERE `User` = '" + Pname + "'";
    try (ResultSet result = db.executeQuery(query)){
                while(result.next())
			{
                String User= result.getString("User");
                int Amount = result.getInt("Amount");
               int addto = 100;  
               int  total = Amount+addto;             
                   db.executeUpdate("UPDATE `Money` SET `Amount` = '" + total + "' WHERE `User` = '" + Pname + "' ");
           chest.clear();
    player.sendTextMessage("[#ffff00] chest id: " + chest.getID());
                     }    
                        }  
                catch (SQLException e)
		{
			e.printStackTrace();
                }
    }

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the problem is with
line 8 on

this is the Whole Block, the cose itself is 300 lines long.

Minotorious · Dec 23rd 2017

ok the null pointer exception probably happens because this line: Item item = chest.getItem(1); returns a null item and then the item.getName().equals("bandage") compares the name of a null value i.e. a null again with the word bandage

LordFoobar · Dec 25th 2017

Quote from Minotorious

ok the null pointer exception probably happens because this line: Item item = chest.getItem(1); returns a null item and then the item.getName().equals("bandage") compares the name of a null value i.e. a null again with the word bandage

Yes. When comparing something in Java, you are better to compare a constant with a variable, or check if the variable has a value first. One of :

if (item.getName() != null && item.getName().equals("bandage")){

or better

if ("bandage".equals(item.getName()){

But in your case, since getName() may be the cause of your NPE, you must check for null, so

if (item != null && "bandage".equals(item.getName()){

King Nothing · Dec 26th 2017

Java

@EventMethod
    public void PlayerInventoryToChestEvent(PlayerInventoryToChestEvent event){
            Player player = event.getPlayer();
    final int infoId = event.getChestID();
    String Pname = player.getName();       
    Chest chest = getWorld().getChest(infoId);
     Item[] Items = chest.getItems();
     // player.sendTextMessage("yes"+NameofItem);
    if (items.getName() != null && item.getName().equals("bandage")){
    }

ive Tried all Three Methods and get "Cannot Find Symbol"

if i use getitem without (1) i get "Found no Arguments"

this CANNOT be done
Maybe Red can explain why we need an argument for getItem();

King Nothing · Dec 26th 2017

It Has to be the limitatons of the API, I know what you are getting at at and

Item item = chest.getItem(); cannot be done.
Item item = chest.getItem(1); this is the Correct Syntax.

King Nothing · Dec 26th 2017

Java

public void PlayerInventoryToChestEvent(PlayerInventoryToChestEvent event){
            Player player = event.getPlayer();
    final int infoId = event.getChestID();
    String Pname = player.getName();       
    Chest chest = getWorld().getChest(infoId);
     Item[] Items = chest.getItems();
     //Item item = event.getItem();
     // player.sendTextMessage("yes"+NameofItem);
    if (Items.getName() != null && Items.getName().equals("bandage")){
        player.sendTextMessage("[#FF0000]BootyBux: ");
    }

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What i Evetually want this to do is check Weather an item is "Sellable" and the Sell Price (the Prices will change and be Written to a databse )
right now this is just to get the man code working,
Im using a chest to "eat"the item and give the correct amout of money for it.

Minotorious · Dec 26th 2017

Quote from Captian_Cornball

Item item = chest.getItem(1); this is the Correct Syntax.

yes this is the correct syntax but that 1 is the slot number in the chest so to access all items in a chest one by one you should use a for loop around that item line.

like this:

Java

int SlotNum = chest.getSlotCount()
for (int i=0;i<SlotNum;i++){
    Item item = chest.getItem(i);
    //do whatever you want to the current item here
    }

King Nothing · Dec 26th 2017

Its STILL giving Null exemtiona

red51 · Dec 26th 2017

If you read an item from a specific chest slot, always make sure the "Item" object isn't null. For example, when reading the item from the first chest slot (Item item = chest.getItem(0);), it returns null if there is no item in this slot.

Quote from Captian_Cornball

Maybe Red can explain why we need an argument for getItem();

[...]

It Has to be the limitatons of the API, I know what you are getting at at and
Item item = chest.getItem(); cannot be done.

This is not a limitation of the API. There is no chest.getItem() function, since it would not make sense. What do you expect such a function to return? A chest has usually more than 1 slot, so it is necessary to specify which item you want to get (from which slot). That's why you have to use the chest.getItem(int slot) function.
If you want to get all Items from a chest instead, you can use the chest.getItems() function, although keep in mind that this returns an array of items.

Quote from Captian_Cornball

Code

Item[] Items = chest.getItems();
//Item item = event.getItem();
// player.sendTextMessage("yes"+NameofItem);
if (Items.getName() != null && Items.getName().equals("bandage")){
    player.sendTextMessage("[#FF0000]BootyBux: ");
}

This does not work: The chest.getItems() function returns an array of all items which are in the chest. You can't call getName() on an array. Arrays in Java do not have any methods. Instead, you need to get a certain item from the array (in this case Item item = Items[0];), or iterate through the array:

Java

Item[] items = chest.getItems();
for(Item item : items){
    if(item != null && item.getName().equals("bandage")){
        player.sendTextMessage("Found bandage!");
        break;
    }
}

King Nothing · Dec 26th 2017

thank you red, It works, this has beemn driving every one NUTS for two days.. just have to igure out how to make it update automatically,

red51 · Dec 26th 2017

I'm glad to hear that

King Nothing · Dec 26th 2017

sometimes i just want to make sweet love to you lol

Participate now!