added go to top button

app/src/main/java/com/greenart7c3/nostrsigner/ui/MainScreen.kt

@@ -17,11 +17,15 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyListState
+import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowUpward
 import androidx.compose.material.icons.filled.ExpandMore
 import androidx.compose.material3.Card
 import androidx.compose.material3.CenterAlignedTopAppBar
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.NavigationBar
@@ -31,6 +35,7 @@ import androidx.compose.material3.SheetValue
 import androidx.compose.material3.Text
 import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -39,6 +44,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.ClipboardManager
+import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.intl.Locale
 import androidx.compose.ui.text.toLowerCase
@@ -126,6 +132,36 @@ fun sendResult(
     activity?.finish()
 }
 
+@Composable
+fun GoToTop(goToTop: () -> Unit) {
+    FloatingActionButton(
+        onClick = goToTop
+    ) {
+        Icon(
+            Icons.Default.ArrowUpward,
+            contentDescription = stringResource(R.string.go_to_top)
+        )
+    }
+}
+
+@Composable
+fun LazyListState.isScrollingUp(): Boolean {
+    var previousIndex by remember(this) { mutableStateOf(firstVisibleItemIndex) }
+    var previousScrollOffset by remember(this) { mutableStateOf(firstVisibleItemScrollOffset) }
+    return remember(this) {
+        derivedStateOf {
+            if (previousIndex != firstVisibleItemIndex) {
+                previousIndex > firstVisibleItemIndex
+            } else {
+                previousScrollOffset >= firstVisibleItemScrollOffset
+            }.also {
+                previousIndex = firstVisibleItemIndex
+                previousScrollOffset = firstVisibleItemScrollOffset
+            }
+        }
+    }.value
+}
+
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun MainScreen(
@@ -145,8 +181,18 @@ fun MainScreen(
         skipPartiallyExpanded = true
     )
     val scope = rememberCoroutineScope()
+    val listState = rememberLazyListState()
 
     Scaffold(
+        floatingActionButton = {
+            if (navBackStackEntry?.destination?.route?.contains("History") == true) {
+                GoToTop {
+                    scope.launch {
+                        listState.scrollToItem(0)
+                    }
+                }
+            }
+        },
         topBar = {
             if (shouldShowBottomSheet) {
                 AccountsBottomSheet(
@@ -268,7 +314,8 @@ fun MainScreen(
                         Modifier
                             .fillMaxSize()
                             .padding(padding)
-                            .padding(16.dp)
+                            .padding(16.dp),
+                        state = listState
                     ) {
                         items(history.size) {
                             Card(

app/src/main/res/values/strings.xml

@@ -79,4 +79,5 @@
     <string name="data_copied_to_the_clipboard">Data copied to the clipboard</string>
     <string name="message_already_encrypted">Message already encrypted</string>
     <string name="relay">Relay</string>
+    <string name="go_to_top">go to top</string>
 </resources>