Update FAQ.md

更新常见问题

art/md/en/FAQ.md

@@ -0,0 +1,65 @@
+# FAQ
+
+## 1.Header and Footer have jump problems after success
+
+This is because you don't set keys for Headers and Footers, because EasyRefresh updates the status of Headers and Footers.
+If the key is not set, the state cannot be recorded and initialized, resulting in a jump.
+
+Sample code
+~~~dart
+  GlobalKey<RefreshHeaderState> _headerKey = new GlobalKey<RefreshHeaderState>();
+  GlobalKey<RefreshFooterState> _footerKey = new GlobalKey<RefreshFooterState>();
+  ....
+    refreshHeader: MaterialHeader(
+        key: _headerKey,
+    ),
+    refreshFooter: MaterialFooter(
+        key: _footerKey,
+    ),
+  ....
+~~~
+
+## 2.CustomScrollView and the use of folded heads
+
+If you use CustomScrollView directly, there may always be hints that no more data is available, even if new data is loaded.
+This is because CustomScrollView does not automatically maintain semanticChildCount, so we need to maintain it ourselves.
+Fold the head in Custom ScrollView using SliverAppBar.
+
+Sample code, complete example[SliverPage](https://github.com/xuelongqy/flutter_easyrefresh/blob/master/example/lib/page/sliver_page.dart)
+~~~dart
+  CustomScrollView(
+    // Manual maintenance of semanticChildCount to determine whether there is no more data
+    semanticChildCount: str.length,
+    slivers: <Widget>[
+      SliverAppBar(
+        floating: false,
+        pinned: true,
+        expandedHeight: 180.0,
+        flexibleSpace: FlexibleSpaceBar(
+          title: Text("CustomScrollView"),
+        ),
+      ),
+      SliverPadding(....)
+    ]
+  )
+~~~
+
+## 3.Using libraries such as flutter_swiper, sliding conflicts occur
+
+This is because UI components in these libraries trigger sliding events, leading to sliding conflicts.
+Use RefreshSafeArea encapsulation, which will not change your interface.
+
+Sample code, complete example[SwiperPage](https://github.com/xuelongqy/flutter_easyrefresh/blob/master/example/lib/page/swiper_page.dart)
+~~~dart
+  RefreshSafeArea(
+    child: Swiper(
+      itemBuilder: (BuildContext context, int index) {
+        return _createMarqueeCard(index);
+      },
+      itemCount: 5,
+      viewportFraction: 0.8,
+      scale: 0.9,
+      autoplay: true,
+    ),
+  );
+~~~