feat: custom buttons for installer screen.

lib/ui/widgets/installerView/custom_material_button.dart

@@ -0,0 +1,68 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_i18n/widgets/I18nText.dart';
+import 'package:revanced_manager/theme.dart';
+
+class CustomMaterialButton extends StatelessWidget {
+  final String text;
+  final bool isFilled;
+  final bool isExpanded;
+  final Function()? onPressed;
+
+  const CustomMaterialButton({
+    Key? key,
+    required this.text,
+    this.isFilled = true,
+    this.isExpanded = false,
+    required this.onPressed,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return TextButton(
+      style: ButtonStyle(
+        padding: MaterialStateProperty.all(
+          isExpanded
+              ? const EdgeInsets.symmetric(
+                  horizontal: 24,
+                  vertical: 12,
+                )
+              : const EdgeInsets.symmetric(
+                  horizontal: 20,
+                  vertical: 12,
+                ),
+        ),
+        shape: MaterialStateProperty.all(
+          RoundedRectangleBorder(
+            borderRadius: BorderRadius.circular(100),
+            side: BorderSide(
+              width: 1,
+              color: Theme.of(context).colorScheme.secondary,
+            ),
+          ),
+        ),
+        side: MaterialStateProperty.all(
+          BorderSide(
+            color: isFilled
+                ? Colors.transparent
+                : Theme.of(context).iconTheme.color!.withOpacity(0.4),
+            width: 1,
+          ),
+        ),
+        backgroundColor: MaterialStateProperty.all(
+          isFilled
+              ? Theme.of(context).colorScheme.secondary
+              : isDark
+                  ? Theme.of(context).colorScheme.background
+                  : Colors.white,
+        ),
+        foregroundColor: MaterialStateProperty.all(
+          isFilled
+              ? Theme.of(context).colorScheme.background
+              : Theme.of(context).colorScheme.secondary,
+        ),
+      ),
+      onPressed: onPressed,
+      child: I18nText(text),
+    );
+  }
+}