Created GuiEntryListEntry interface for GuiEntryList contained classes to avoid toString() methods from having to be abused

Created GuiFileChooser and according Listeners
Added (non-functional) GuiAssetAdder for CustomImageObjects

src/main/java/eu/crushedpixel/replaymod/gui/GuiAssetAdder.java

@@ -0,0 +1,101 @@
+package eu.crushedpixel.replaymod.gui;
+
+import eu.crushedpixel.replaymod.ReplayMod;
+import eu.crushedpixel.replaymod.gui.elements.GuiAdvancedTextField;
+import eu.crushedpixel.replaymod.gui.elements.GuiEntryList;
+import eu.crushedpixel.replaymod.gui.elements.GuiFileChooser;
+import eu.crushedpixel.replaymod.gui.elements.GuiNumberInput;
+import eu.crushedpixel.replaymod.gui.elements.listeners.FileChooseListener;
+import eu.crushedpixel.replaymod.holders.CustomImageObject;
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.GuiScreen;
+import net.minecraft.client.resources.I18n;
+import net.minecraftforge.fml.client.config.GuiCheckBox;
+
+import javax.imageio.ImageIO;
+import java.awt.*;
+import java.io.File;
+
+public class GuiAssetAdder extends GuiScreen {
+
+    private String screenTitle;
+
+    private boolean initialized = false;
+
+    private GuiEntryList<CustomImageObject> objectList;
+    private GuiButton removeButton;
+    private GuiFileChooser addButton;
+    private GuiFileChooser guiFileChooser;
+
+    private GuiAdvancedTextField nameInput;
+
+    private GuiNumberInput xInput, yInput, zInput, yawInput, pitchInput, rollInput, scaleInput;
+    private GuiCheckBox backVisibleCheckBox;
+
+    public GuiAssetAdder() {
+        ReplayMod.replaySender.setReplaySpeed(0);
+    }
+
+    @Override
+    public void initGui() {
+        if(!initialized) {
+            screenTitle = I18n.format("replaymod.gui.assets.title");
+
+            objectList = new GuiEntryList<CustomImageObject>(0, fontRendererObj, 0, 0, 0, 0);
+            removeButton = new GuiButton(GuiConstants.ASSET_ADDER_REMOVE_BUTTON, 0, 0, I18n.format("replaymod.gui.remove"));
+
+            addButton = new GuiFileChooser(1, 0, 0, I18n.format("replaymod.gui.add"), null, ImageIO.getReaderFileSuffixes()) {
+                @Override protected void updateDisplayString() {}
+            };
+
+            addButton.registerListener(new FileChooseListener() {
+                @Override
+                public void onFileChosen(File file) {
+
+                }
+            });
+
+            guiFileChooser = new GuiFileChooser(2, 0, 0, I18n.format("replaymod.gui.assets.filechooser")+": ", null, ImageIO.getReaderFileSuffixes());
+        }
+
+        int h = (int)Math.floor(((double)this.height-(45+20+15+20))/14);
+
+        objectList.width = guiFileChooser.width = 150;
+        objectList.xPosition = width/2 - objectList.width - 5;
+        objectList.setVisibleElements(h);
+        objectList.yPosition = 45;
+
+        addButton.width = removeButton.width = 75;
+        addButton.xPosition = objectList.xPosition;
+        removeButton.xPosition = addButton.xPosition+addButton.width;
+        addButton.yPosition = removeButton.yPosition = objectList.yPosition + objectList.height + 2;
+
+        guiFileChooser.xPosition = this.width/2 + 5;
+        guiFileChooser.yPosition = 45;
+
+        buttonList.add(removeButton);
+        buttonList.add(addButton);
+        buttonList.add(guiFileChooser);
+
+        initialized = true;
+    }
+
+    @Override
+    public void drawScreen(int mouseX, int mouseY, float partialTicks) {
+        this.drawCenteredString(fontRendererObj, screenTitle, this.width / 2, 5, Color.WHITE.getRGB());
+
+        int leftBorder = 10;
+        int topBorder = 20;
+
+        drawGradientRect(leftBorder, topBorder, width - leftBorder, this.height - 10, -1072689136, -804253680);
+
+        objectList.drawTextBox();
+
+        super.drawScreen(mouseX, mouseY, partialTicks);
+    }
+
+    @Override
+    public void updateScreen() {
+        super.updateScreen();
+    }
+}