[API] Implement ImGuiFileDialog extension (#89)

* Initial setup for ImGuiFileDialog extension

* Need to resolve linker errors. Working on PaneFun callback.

* Remove jni callback code that is not compiling to expose linker error.

* Callbacks for paneFun not yet implemented. Linker error still present, seems that some header is being included multiple times.

* Fixed linker errors. Added example for demo.

* Add support for multiple callbacks

* Callbacks work

example/src/main/java/ExampleImGuiFileDialog.java

@@ -0,0 +1,61 @@
+import imgui.extension.imguifiledialog.ImGuiFileDialog;
+import imgui.extension.imguifiledialog.callback.ImGuiFileDialogPaneFun;
+import imgui.extension.imguifiledialog.flag.ImGuiFileDialogFlags;
+import imgui.flag.ImGuiCond;
+import imgui.internal.ImGui;
+import imgui.type.ImBoolean;
+
+import java.awt.*;
+import java.net.URI;
+import java.util.Map;
+
+public class ExampleImGuiFileDialog {
+    private static final String URL = "https://github.com/aiekick/ImGuiFileDialog";
+
+    private static Map<String, String> selection = null;
+    private static long userData = 0;
+    private static ImGuiFileDialogPaneFun callback = new ImGuiFileDialogPaneFun() {
+        @Override
+        public void paneFun(String filter, long userDatas, boolean canContinue) {
+            ImGui.text("Filter: " + filter);
+        }
+    };
+
+    public static void show(ImBoolean showImGuiFileDialogDemo) {
+        ImGui.setNextWindowSize(800, 200, ImGuiCond.Once);
+        ImGui.setNextWindowPos(ImGui.getMainViewport().getPosX() + 100, ImGui.getMainViewport().getPosY() + 100, ImGuiCond.Once);
+        if (ImGui.begin("ImGuiFileDialogDemo Demo", showImGuiFileDialogDemo)) {
+            ImGui.text("This a demo for ImGuiFileDialog");
+
+            ImGui.alignTextToFramePadding();
+            ImGui.text("Repo:");
+            ImGui.sameLine();
+            if (ImGui.button(URL)) {
+                try {
+                    Desktop.getDesktop().browse(new URI(URL));
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+
+            if (ImGui.button("Browse File")) {
+                ImGuiFileDialog.openModal("browse-key", "Choose File", ".java", ".", callback, 250, 1, 42, ImGuiFileDialogFlags.None);
+            }
+
+            if (ImGuiFileDialog.display("browse-key", ImGuiFileDialogFlags.None, 200, 400, 800, 600)) {
+                if (ImGuiFileDialog.isOk()) {
+                    selection = ImGuiFileDialog.getSelection();
+                    userData = ImGuiFileDialog.getUserDatas();
+                }
+                ImGuiFileDialog.close();
+            }
+        }
+
+        if (selection != null && !selection.isEmpty()) {
+            ImGui.text("Selected: " + selection.values().stream().findFirst().get());
+            ImGui.text("User Data: " + userData);
+        }
+
+        ImGui.end();
+    }
+}

example/src/main/java/Extra.java

@@ -10,6 +10,7 @@ public class Extra {
     private static final ImBoolean SHOW_IMPLOT_DEMO_WINDOW = new ImBoolean(false);
     private static final ImBoolean SHOW_IMGUIZMO_DEMO = new ImBoolean(false);
     private static final ImBoolean SHOW_IMGUI_COLOR_TEXT_EDIT_WINDOW = new ImBoolean(false);
+    private static final ImBoolean SHOW_IMGUI_FILE_DIALOG_WINDOW = new ImBoolean(false);
 
     private static final Graph GRAPH = new Graph();
 
@@ -22,6 +23,7 @@ public class Extra {
         ImGui.checkbox("Show ImPlot Demo Window", SHOW_IMPLOT_DEMO_WINDOW);
         ImGui.checkbox("Show ImGuizmo Demo Window", SHOW_IMGUIZMO_DEMO);
         ImGui.checkbox("Show ImGuiColorTextEdit Demo Window", SHOW_IMGUI_COLOR_TEXT_EDIT_WINDOW);
+        ImGui.checkbox("Show ImGuiFileDialog Demo Window", SHOW_IMGUI_FILE_DIALOG_WINDOW);
 
         if (SHOW_DEMO_WINDOW.get()) {
             ImGui.showDemoWindow(SHOW_DEMO_WINDOW);
@@ -50,5 +52,9 @@ public class Extra {
         if (SHOW_IMGUI_COLOR_TEXT_EDIT_WINDOW.get()) {
             ExampleImGuiColorTextEdit.show(SHOW_IMGUI_COLOR_TEXT_EDIT_WINDOW);
         }
+
+        if (SHOW_IMGUI_FILE_DIALOG_WINDOW.get()) {
+            ExampleImGuiFileDialog.show(SHOW_IMGUI_FILE_DIALOG_WINDOW);
+        }
     }
 }