Add scroll-to-top on back

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

src/components/hideableHeader.tsx

@@ -0,0 +1,63 @@
+import React, { useEffect, useRef } from 'react';
+import { Animated, StyleSheet } from 'react-native';
+import { useDimensions } from '../contexts';
+import styles from '../styles';
+import { useTheme } from 'react-native-paper';
+
+const hideableHeaderStyles = StyleSheet.create({
+  headerView: {
+    position: 'absolute',
+    top: 0,
+    left: 0,
+    right: 0,
+    zIndex: 100,
+  },
+});
+
+const HideableHeader = ({
+  visible = true,
+  children,
+}: {
+  visible?: boolean;
+  children: React.ReactNode;
+}) => {
+  const { colors } = useTheme();
+  const { orientation } = useDimensions();
+
+  const headerAnim = useRef(new Animated.Value(visible ? 1 : 0)).current;
+
+  useEffect(() => {
+    Animated.timing(headerAnim, {
+      toValue: visible ? 1 : 0,
+      duration: visible ? 200 : 150,
+      useNativeDriver: true,
+    }).start();
+  }, [headerAnim, visible]);
+
+  return (
+    <Animated.View
+      style={[
+        hideableHeaderStyles.headerView,
+        orientation == 'portrait' && styles.paddingTop,
+        orientation == 'landscape' && styles.smallPaddingTop,
+        styles.paddingHorizontal,
+        {
+          transform: [
+            {
+              translateY: headerAnim.interpolate({
+                inputRange: [0, 1],
+                outputRange: [-130, 0],
+              }),
+            },
+          ],
+        },
+        {
+          backgroundColor: colors.background,
+        },
+      ]}>
+      {children}
+    </Animated.View>
+  );
+};
+
+export default HideableHeader;

src/components/index.ts

@@ -1,5 +1,6 @@
 export { default as FloatingActionButton } from './floatingActionButton';
 export { default as HideableBottomNavigationBar } from './hideableBottomNavigationBar';
+export { default as HideableHeader } from './hideableHeader';
 export { default as LoadingView } from './loadingView';
-export { default as TagChip } from './tagChip';
-export { default as TagPreview } from './tagPreview';
+export { default as TagChip } from './tags/tagChip';
+export { default as TagPreview } from './tags/tagPreview';

src/components/tags/tagChip.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
-import { getContrastColor } from '../utilities';
+import { getContrastColor } from '../../utilities';
 import { Chip } from 'react-native-paper';
-import { Tag } from '../database';
+import { Tag } from '../../database';
 import FontAwesome5 from 'react-native-vector-icons/FontAwesome5';
 
 const TagChip = ({ tag }: { tag: Tag }) => {

src/components/tags/tagPreview.tsx

@@ -2,9 +2,9 @@ import React from 'react';
 import { StyleSheet, View } from 'react-native';
 import FontAwesome5 from 'react-native-vector-icons/FontAwesome5';
 import { Chip } from 'react-native-paper';
-import styles from '../styles';
-import { useDimensions } from '../contexts';
-import { getContrastColor } from '../utilities';
+import styles from '../../styles';
+import { useDimensions } from '../../contexts';
+import { getContrastColor } from '../../utilities';
 
 const tagPreviewStyles = StyleSheet.create({
   chip: {

src/screens/tags.tsx

@@ -1,11 +1,11 @@
-import React, { useEffect, useRef, useState } from 'react';
+import React, { useCallback, useRef, useState } from 'react';
 import {
   StyleSheet,
   View,
   Text,
   NativeSyntheticEvent,
   NativeScrollEvent,
-  Animated,
+  BackHandler,
 } from 'react-native';
 import {
   Button,
@@ -19,7 +19,12 @@ import {
 import { useQuery } from '@realm/react';
 import { useDispatch, useSelector } from 'react-redux';
 import { FlashList } from '@shopify/flash-list';
-import { TagChip } from '../components';
+import {
+  NavigationProp,
+  useFocusEffect,
+  useNavigation,
+} from '@react-navigation/native';
+import { HideableHeader, TagChip } from '../components';
 import { Tag } from '../database';
 import styles from '../styles';
 import {
@@ -37,17 +42,8 @@ import {
   tagSortQuery,
 } from '../types';
 import { getSortIcon } from '../utilities';
-import { useDimensions } from '../contexts';
-import { NavigationProp, useNavigation } from '@react-navigation/native';
 
 const tagsStyles = StyleSheet.create({
-  headerView: {
-    position: 'absolute',
-    top: 0,
-    left: 0,
-    right: 0,
-    zIndex: 100,
-  },
   headerButtonView: {
     height: 50,
   },
@@ -74,8 +70,7 @@ const tagsStyles = StyleSheet.create({
 
 const Tags = () => {
   const { colors } = useTheme();
-  const { orientation } = useDimensions();
-  const navigation = useNavigation<NavigationProp<RootStackParamList>>();
+  const { navigate } = useNavigation<NavigationProp<RootStackParamList>>();
   const sort = useSelector((state: RootState) => state.tags.sort);
   const sortDirection = useSelector(
     (state: RootState) => state.tags.sortDirection,
@@ -101,16 +96,6 @@ const Tags = () => {
     setSortMenuVisible(false);
   };
 
-  const sortMenuAnim = useRef(new Animated.Value(navVisisble ? 1 : 0)).current;
-
-  useEffect(() => {
-    Animated.timing(sortMenuAnim, {
-      toValue: navVisisble ? 1 : 0,
-      duration: navVisisble ? 200 : 150,
-      useNativeDriver: true,
-    }).start();
-  }, [navVisisble, sortMenuAnim]);
-
   const [search, setSearch] = useState('');
 
   const tags = useQuery<Tag>(
@@ -132,17 +117,33 @@ const Tags = () => {
 
     if (currentOffset <= 150) {
       dispatch(setNavVisible(true));
-      setScrollOffset(0);
-      return;
+    } else {
+      const diff = currentOffset - scrollOffset;
+      if (Math.abs(diff) > 50) dispatch(setNavVisible(diff < 0));
     }
 
-    const diff = currentOffset - scrollOffset;
-    if (Math.abs(diff) < 50) return;
-
-    dispatch(setNavVisible(diff < 0));
     setScrollOffset(currentOffset);
   };
 
+  const flashListRef = useRef<FlashList<Tag>>(null);
+
+  useFocusEffect(
+    useCallback(() => {
+      const handleBackPress = () => {
+        if (scrollOffset > 0) {
+          flashListRef.current?.scrollToOffset({ offset: 0, animated: true });
+          return true;
+        }
+        return false;
+      };
+
+      BackHandler.addEventListener('hardwareBackPress', handleBackPress);
+
+      return () =>
+        BackHandler.removeEventListener('hardwareBackPress', handleBackPress);
+    }, [flashListRef, scrollOffset]),
+  );
+
   return (
     <View
       style={[
@@ -150,26 +151,7 @@ const Tags = () => {
         styles.fullSize,
         { backgroundColor: colors.background },
       ]}>
-      <Animated.View
-        style={[
-          tagsStyles.headerView,
-          orientation == 'portrait' && styles.paddingTop,
-          orientation == 'landscape' && styles.smallPaddingTop,
-          styles.paddingHorizontal,
-          {
-            transform: [
-              {
-                translateY: sortMenuAnim.interpolate({
-                  inputRange: [0, 1],
-                  outputRange: [-130, 0],
-                }),
-              },
-            ],
-          },
-          {
-            backgroundColor: colors.background,
-          },
-        ]}>
+      <HideableHeader visible={navVisisble}>
         <Searchbar
           placeholder="Search Tags"
           value={search}
@@ -209,15 +191,16 @@ const Tags = () => {
           </Menu>
         </View>
         <Divider />
-      </Animated.View>
+      </HideableHeader>
       <FlashList
+        ref={flashListRef}
         data={tags}
         estimatedItemSize={52}
         showsVerticalScrollIndicator={false}
         renderItem={({ item: tag }) => (
           <TouchableRipple
             onPress={() =>
-              navigation.navigate(ROUTE.EDIT_TAG, { id: tag.id.toHexString() })
+              navigate(ROUTE.EDIT_TAG, { id: tag.id.toHexString() })
             }>
             <View style={tagsStyles.tagRow}>
               <View style={tagsStyles.tagView}>

src/styles.tsx

@@ -14,16 +14,16 @@ const styles = StyleSheet.create({
     paddingTop: '2%',
   },
   padding: {
-    padding: '5%',
+    padding: '4%',
   },
   paddingHorizontal: {
-    paddingHorizontal: '5%',
+    paddingHorizontal: '4%',
   },
   paddingVertical: {
-    paddingVertical: '5%',
+    paddingVertical: '4%',
   },
   paddingTop: {
-    paddingTop: '5%',
+    paddingTop: '4%',
   },
   centered: {
     justifyContent: 'center',