Add new (non-functional) button to edit world screen

src/main/java/ml/unbreakinggold/datapackinstaller/mixin/EditWorldScreenMixin.java

@@ -0,0 +1,29 @@
+package ml.unbreakinggold.datapackinstaller.mixin;
+
+import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.screen.world.EditWorldScreen;
+import net.minecraft.client.gui.widget.ButtonWidget;
+import net.minecraft.client.gui.widget.DirectionalLayoutWidget;
+import net.minecraft.text.Text;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.Unique;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(EditWorldScreen.class)
+public class EditWorldScreenMixin extends Screen {
+    @Shadow @Final private DirectionalLayoutWidget layout;
+    @Unique private static final Text SELECT_DATAPACKS_TEXT = Text.translatable("selectWorld.edit.datapacks");
+
+    protected EditWorldScreenMixin(Text title) {
+        super(title);
+    }
+
+    @Inject(at = @At(value = "INVOKE", target = "Lnet/minecraft/client/gui/widget/EmptyWidget;<init>(II)V"), method = "<init>")
+    private void addButton(CallbackInfo info) {
+        this.layout.add(ButtonWidget.builder(SELECT_DATAPACKS_TEXT, (button) -> {}).width(200).build());
+    }
+}

src/main/resources/DatapackInstaller.mixins.json

@@ -6,7 +6,8 @@
   "mixins": [
   ],
   "client": [
-    "CreateWorldScreenMixin"
+    "CreateWorldScreenMixin",
+    "EditWorldScreenMixin"
   ],
   "injectors": {
     "defaultRequire": 1

src/main/resources/assets/datapackinstaller/lang/en_us.json

@@ -0,0 +1,3 @@
+{
+  "selectWorld.edit.datapacks": "Select Datapacks"
+}