Page & Tab change handler

InvUI/src/main/java/de/studiocode/invui/gui/impl/PagedGUI.java

@@ -19,7 +19,7 @@ public abstract class PagedGUI extends BaseGUI {
     
     private final boolean infinitePages;
     private final int[] itemListSlots;
-    protected int currentPage;
+    private int currentPage;
     
     public PagedGUI(int width, int height, boolean infinitePages, int... itemListSlots) {
         super(width, height);
@@ -33,17 +33,21 @@ public abstract class PagedGUI extends BaseGUI {
     }
     
     public void goForward() {
-        if (hasNextPage()) {
+        if (hasNextPage())
-            currentPage++;
+            setPage(currentPage + 1);
-            update();
-        }
     }
     
     public void goBack() {
-        if (hasPageBefore()) {
+        if (hasPageBefore())
-            currentPage--;
+            setPage(currentPage - 1);
-            update();
     }
+    
+    public void setPage(int page) {
+        int previous = currentPage;
+        currentPage = page;
+        update();
+        if (previous != currentPage)
+            handlePageChange(previous, currentPage);
     }
     
     public boolean hasNextPage() {
@@ -93,4 +97,6 @@ public abstract class PagedGUI extends BaseGUI {
     
     protected abstract List<SlotElement> getPageElements(int page);
     
+    protected abstract void handlePageChange(int previous, int now);
+    
 }

InvUI/src/main/java/de/studiocode/invui/gui/impl/ScrollGUI.java

@@ -106,8 +106,8 @@ public abstract class ScrollGUI extends BaseGUI {
         }
     }
     
-    abstract protected int getMaxLineIndex();
+    protected abstract int getMaxLineIndex();
     
-    abstract protected List<? extends SlotElement> getElements(int from, int to);
+    protected abstract List<? extends SlotElement> getElements(int from, int to);
     
 }

InvUI/src/main/java/de/studiocode/invui/gui/impl/SimplePagedItemsGUI.java

@@ -10,6 +10,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
 /**
@@ -21,6 +22,7 @@ import java.util.stream.Collectors;
 public class SimplePagedItemsGUI extends PagedGUI {
     
     private List<Item> items;
+    private List<BiConsumer<Integer, Integer>> pageChangeHandlers;
     
     public SimplePagedItemsGUI(int width, int height, @Nullable List<Item> items, int... itemListSlots) {
         super(width, height, false, itemListSlots);
@@ -37,6 +39,29 @@ public class SimplePagedItemsGUI extends PagedGUI {
         return (int) Math.ceil((double) items.size() / (double) getItemListSlots().length);
     }
     
+    public void setItems(@Nullable List<Item> items) {
+        this.items = items != null ? items : new ArrayList<>();
+        update();
+    }
+    
+    public void addPageChangeHandler(@NotNull BiConsumer<Integer, Integer> pageChangeHandler) {
+        if (pageChangeHandlers == null) pageChangeHandlers = new ArrayList<>();
+        pageChangeHandlers.add(pageChangeHandler);
+    }
+    
+    public void removePageChangeHandler(@NotNull BiConsumer<Integer, Integer> pageChangeHandler) {
+        if (pageChangeHandlers != null) pageChangeHandlers.remove(pageChangeHandler);
+    }
+    
+    @Nullable
+    public List<BiConsumer<Integer, Integer>> getPageChangeHandlers() {
+        return pageChangeHandlers;
+    }
+    
+    public void setPageChangeHandlers(@Nullable List<BiConsumer<Integer, Integer>> pageChangeHandlers) {
+        this.pageChangeHandlers = pageChangeHandlers;
+    }
+    
     @Override
     protected List<SlotElement> getPageElements(int page) {
         int length = getItemListSlots().length;
@@ -46,9 +71,9 @@ public class SimplePagedItemsGUI extends PagedGUI {
         return items.subList(from, to).stream().map(ItemSlotElement::new).collect(Collectors.toList());
     }
     
-    public void setItems(@Nullable List<Item> items) {
+    @Override
-        this.items = items != null ? items : new ArrayList<>();
+    protected void handlePageChange(int previous, int now) {
-        update();
+        if (pageChangeHandlers != null) pageChangeHandlers.forEach(handler -> handler.accept(previous, now));
     }
     
 }

InvUI/src/main/java/de/studiocode/invui/gui/impl/SimplePagedNestedGUI.java

@@ -9,6 +9,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
@@ -21,6 +22,7 @@ import java.util.stream.IntStream;
 public class SimplePagedNestedGUI extends PagedGUI {
     
     private List<GUI> guis;
+    private List<BiConsumer<Integer, Integer>> pageChangeHandlers;
     
     public SimplePagedNestedGUI(int width, int height, @Nullable List<GUI> guis, int... itemListSlots) {
         super(width, height, false, itemListSlots);
@@ -37,6 +39,34 @@ public class SimplePagedNestedGUI extends PagedGUI {
         return guis.size();
     }
     
+    public void setGuis(@Nullable List<GUI> guis) {
+        this.guis = guis == null ? new ArrayList<>() : guis;
+        update();
+    }
+    
+    public void addPageChangeHandler(@NotNull BiConsumer<Integer, Integer> pageChangeHandler) {
+        if (pageChangeHandlers == null) pageChangeHandlers = new ArrayList<>();
+        pageChangeHandlers.add(pageChangeHandler);
+    }
+    
+    public void removePageChangeHandler(@NotNull BiConsumer<Integer, Integer> pageChangeHandler) {
+        if (pageChangeHandlers != null) pageChangeHandlers.remove(pageChangeHandler);
+    }
+    
+    @Nullable
+    public List<BiConsumer<Integer, Integer>> getPageChangeHandlers() {
+        return pageChangeHandlers;
+    }
+    
+    public void setPageChangeHandlers(@Nullable List<BiConsumer<Integer, Integer>> pageChangeHandlers) {
+        this.pageChangeHandlers = pageChangeHandlers;
+    }
+    
+    @Override
+    protected void handlePageChange(int previous, int now) {
+        if (pageChangeHandlers != null) pageChangeHandlers.forEach(handler -> handler.accept(previous, now));
+    }
+    
     @Override
     protected List<SlotElement> getPageElements(int page) {
         if (guis.size() <= page) return new ArrayList<>();
@@ -49,9 +79,4 @@ public class SimplePagedNestedGUI extends PagedGUI {
             .collect(Collectors.toList());
     }
     
-    public void setGuis(@Nullable List<GUI> guis) {
-        this.guis = guis == null ? new ArrayList<>() : guis;
-        update();
-    }
-    
 }

InvUI/src/main/java/de/studiocode/invui/gui/impl/SimpleTabGUI.java

@@ -6,10 +6,12 @@ import de.studiocode.invui.gui.SlotElement.LinkedSlotElement;
 import de.studiocode.invui.gui.builder.GUIBuilder;
 import de.studiocode.invui.gui.structure.Structure;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.stream.Collectors;
 
 /**
@@ -21,6 +23,7 @@ public class SimpleTabGUI extends TabGUI {
     
     private final List<GUI> tabs;
     private final List<List<SlotElement>> linkingElements;
+    private List<BiConsumer<Integer, Integer>> tabChangeHandlers;
     
     public SimpleTabGUI(int width, int height, @NotNull List<GUI> tabs, int[] listSlots) {
         super(width, height, tabs.size(), listSlots);
@@ -54,14 +57,37 @@ public class SimpleTabGUI extends TabGUI {
         return Collections.unmodifiableList(tabs);
     }
     
-    @Override
-    public List<SlotElement> getSlotElements(int tab) {
-        return linkingElements.get(tab);
-    }
-    
     @Override
     public boolean isTabAvailable(int tab) {
         return tabs.get(tab) != null;
     }
     
+    public void addTabChangeHandler(@NotNull BiConsumer<Integer, Integer> tabChangeHandler) {
+        if (tabChangeHandlers == null) tabChangeHandlers = new ArrayList<>();
+        tabChangeHandlers.add(tabChangeHandler);
+    }
+    
+    public void removeTabChangeHandler(@NotNull BiConsumer<Integer, Integer> tabChangeHandler) {
+        if (tabChangeHandlers != null) tabChangeHandlers.remove(tabChangeHandler);
+    }
+    
+    @Nullable
+    public List<BiConsumer<Integer, Integer>> getTabChangeHandlers() {
+        return tabChangeHandlers;
+    }
+    
+    public void setTabChangeHandlers(@Nullable List<BiConsumer<Integer, Integer>> tabChangeHandlers) {
+        this.tabChangeHandlers = tabChangeHandlers;
+    }
+    
+    @Override
+    protected void handleTabChange(int previous, int now) {
+        if (tabChangeHandlers != null) tabChangeHandlers.forEach(handler -> handler.accept(previous, now));
+    }
+    
+    @Override
+    protected List<SlotElement> getSlotElements(int tab) {
+        return linkingElements.get(tab);
+    }
+    
 }

InvUI/src/main/java/de/studiocode/invui/gui/impl/TabGUI.java

@@ -31,8 +31,11 @@ public abstract class TabGUI extends BaseGUI implements Controllable {
         if (!isTabAvailable(tab))
             return;
         
+        int previous = currentTab;
         currentTab = tab;
         update();
+        
+        handleTabChange(previous, currentTab);
     }
     
     protected void update() {
@@ -63,8 +66,10 @@ public abstract class TabGUI extends BaseGUI implements Controllable {
         return currentTab;
     }
     
-    public abstract List<SlotElement> getSlotElements(int tab);
-    
     public abstract boolean isTabAvailable(int tab);
     
+    protected abstract List<SlotElement> getSlotElements(int tab);
+    
+    protected abstract void handleTabChange(int previous, int now);
+    
 }