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Add option to scroll to and open a channel from the channel list (#932)
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‎CHANGELOG.md‎

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Original file line numberDiff line numberDiff line change
@@ -3,6 +3,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
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# Upcoming
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### ✅ Added
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- Add option to scroll to and open a channel from the channel list [#932](https://github.com/GetStream/stream-chat-swiftui/pull/932)
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### 🐞 Fixed
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- Show attachment title instead of URL in the `FileAttachmentPreview` view [#930](https://github.com/GetStream/stream-chat-swiftui/pull/930)
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- Fix overriding title color in `ChannelTitleView` [#931](https://github.com/GetStream/stream-chat-swiftui/pull/931)

‎Sources/StreamChatSwiftUI/ChatChannelList/ChatChannelList.swift‎

Lines changed: 14 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,7 @@ public struct ChannelList<Factory: ViewFactory>: View {
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var channels: LazyCachedMapCollection<ChatChannel>
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@Binding var selectedChannel: ChannelSelectionInfo?
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@Binding var swipedChannelId: String?
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@Binding var scrolledChannelId: String?
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private var scrollable: Bool
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private var onlineIndicatorShown: (ChatChannel) -> Bool
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private var imageLoader: (ChatChannel) -> UIImage
@@ -30,6 +31,7 @@ public struct ChannelList<Factory: ViewFactory>: View {
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channels: LazyCachedMapCollection<ChatChannel>,
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selectedChannel: Binding<ChannelSelectionInfo?>,
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swipedChannelId: Binding<String?>,
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scrolledChannelId: Binding<String?> = .constant(nil),
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scrollable: Bool = true,
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onlineIndicatorShown: ((ChatChannel) -> Bool)? = nil,
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imageLoader: ((ChatChannel) -> UIImage)? = nil,
@@ -72,13 +74,23 @@ public struct ChannelList<Factory: ViewFactory>: View {
7274
self.scrollable = scrollable
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_selectedChannel = selectedChannel
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_swipedChannelId = swipedChannelId
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_scrolledChannelId = scrolledChannelId
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}
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public var body: some View {
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Group {
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if scrollable {
80-
ScrollView {
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channelsVStack
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ScrollViewReader { scrollView in
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ScrollView {
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channelsVStack
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}
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.onChange(of: scrolledChannelId) { newValue in
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if let newValue {
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withAnimation {
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scrollView.scrollTo(newValue, anchor: .bottom)
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}
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}
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}
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}
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} else {
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channelsVStack

‎Sources/StreamChatSwiftUI/ChatChannelList/ChatChannelListView.swift‎

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Original file line numberDiff line numberDiff line change
@@ -234,6 +234,7 @@ public struct ChatChannelListContentView<Factory: ViewFactory>: View {
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channels: viewModel.channels,
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selectedChannel: $viewModel.selectedChannel,
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swipedChannelId: $viewModel.swipedChannelId,
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scrolledChannelId: $viewModel.scrolledChannelId,
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onlineIndicatorShown: viewModel.onlineIndicatorShown(for:),
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imageLoader: channelHeaderLoader.image(for:),
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onItemTap: onItemTap,

‎Sources/StreamChatSwiftUI/ChatChannelList/ChatChannelListViewModel.swift‎

Lines changed: 43 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -39,6 +39,9 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
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4040
/// Index of the selected channel.
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private var selectedChannelIndex: Int?
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/// When set, scrolls to the specified channel id (if it exists).
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@Published public var scrolledChannelId: String?
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4346
/// Published variables.
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@Published public var channels = LazyCachedMapCollection<ChatChannel>() {
@@ -180,6 +183,38 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
180183
}
181184
}
182185
}
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/// Opens the chat channel destination with the provided channel id.
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///
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/// - Parameter channelId: the id of the channel that will be shown.
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public func openChannel(with channelId: ChannelId) {
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func loadUntilFound() {
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guard let controller else { return }
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if let channel = controller.channels.first(where: { $0.id == channelId.rawValue }) {
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log.debug("Showing channel with id \(channelId)")
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scrollToAndOpen(channel: channel)
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return
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}
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// Stop if there are no more channels to load
200+
if controller.hasLoadedAllPreviousChannels {
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scrolledChannelId = nil
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return
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}
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controller.loadNextChannels { [weak self] error in
206+
if error != nil {
207+
self?.scrolledChannelId = nil
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return
209+
}
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DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
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loadUntilFound()
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}
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}
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}
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loadUntilFound()
217+
}
183218

184219
public func loadAdditionalSearchResults(index: Int) {
185220
switch searchType {
@@ -543,6 +578,14 @@ open class ChatChannelListViewModel: ObservableObject, ChatChannelListController
543578
markDirty = true
544579
channels = LazyCachedMapCollection(source: temp, map: { $0 })
545580
}
581+
582+
private func scrollToAndOpen(channel: ChatChannel) {
583+
scrolledChannelId = channel.id
584+
DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) { [weak self] in
585+
self?.selectedChannel = .init(channel: channel, message: nil)
586+
self?.scrolledChannelId = nil
587+
}
588+
}
546589

547590
private func observeChannelDismiss() {
548591
NotificationCenter.default.addObserver(

‎StreamChatSwiftUITests/Tests/ChatChannelList/ChatChannelListViewModel_Tests.swift‎

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Original file line numberDiff line numberDiff line change
@@ -372,6 +372,126 @@ class ChatChannelListViewModel_Tests: StreamChatTestCase {
372372
XCTAssertNotNil(viewModel.messageSearchController)
373373
}
374374

375+
// MARK: - Open Channel
376+
377+
func test_openChannel_whenChannelExistsInList_shouldScrollToAndOpenChannel() {
378+
// Given
379+
let channel = ChatChannel.mockDMChannel()
380+
let channelListController = makeChannelListController(channels: [channel])
381+
let viewModel = ChatChannelListViewModel(
382+
channelListController: channelListController,
383+
selectedChannelId: nil
384+
)
385+
386+
// When
387+
viewModel.openChannel(with: channel.cid)
388+
389+
// Then
390+
XCTAssertEqual(viewModel.scrolledChannelId, channel.id)
391+
392+
// Wait for the async delay and verify selectedChannel is set
393+
let expectation = XCTestExpectation(description: "Channel opened")
394+
DispatchQueue.main.asyncAfter(deadline: .now() + 0.4) {
395+
XCTAssertEqual(viewModel.selectedChannel?.channel.id, channel.id)
396+
XCTAssertNil(viewModel.scrolledChannelId)
397+
expectation.fulfill()
398+
}
399+
wait(for: [expectation], timeout: 1.0)
400+
}
401+
402+
func test_openChannel_whenChannelNotInList_shouldLoadNextChannelsUntilFound() {
403+
// Given
404+
let existingChannel = ChatChannel.mockDMChannel()
405+
let targetChannel = ChatChannel.mockDMChannel()
406+
let channelListController = makeChannelListController(channels: [existingChannel])
407+
let viewModel = ChatChannelListViewModel(
408+
channelListController: channelListController,
409+
selectedChannelId: nil
410+
)
411+
412+
// When
413+
viewModel.openChannel(with: targetChannel.cid)
414+
415+
// Then
416+
XCTAssertEqual(channelListController.loadNextChannelsCallCount, 1)
417+
418+
// Simulate the channel being found after loading
419+
channelListController.simulate(
420+
channels: [existingChannel, targetChannel],
421+
changes: [.insert(targetChannel, index: .init(row: 1, section: 0))]
422+
)
423+
424+
// When
425+
viewModel.openChannel(with: targetChannel.cid)
426+
427+
// Verify the channel is eventually opened
428+
let expectation = XCTestExpectation(description: "Channel opened after loading")
429+
DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
430+
XCTAssertEqual(viewModel.selectedChannel?.channel.id, targetChannel.id)
431+
XCTAssertNil(viewModel.scrolledChannelId)
432+
expectation.fulfill()
433+
}
434+
wait(for: [expectation], timeout: 1.0)
435+
}
436+
437+
func test_openChannel_whenChannelNotFoundAndNoMoreChannels_shouldSetScrolledChannelIdToNil() {
438+
// Given
439+
let existingChannel = ChatChannel.mockDMChannel()
440+
let targetChannel = ChatChannel.mockDMChannel()
441+
let channelListController = makeChannelListController(channels: [existingChannel])
442+
let viewModel = ChatChannelListViewModel(
443+
channelListController: channelListController,
444+
selectedChannelId: nil
445+
)
446+
447+
// When
448+
viewModel.openChannel(with: targetChannel.cid)
449+
450+
// Then
451+
XCTAssertNil(viewModel.scrolledChannelId)
452+
XCTAssertNil(viewModel.selectedChannel)
453+
}
454+
455+
func test_openChannel_whenChannelFoundAfterMultipleLoads_shouldEventuallyOpenChannel() {
456+
// Given
457+
let existingChannel = ChatChannel.mockDMChannel()
458+
let targetChannel = ChatChannel.mockDMChannel()
459+
let channelListController = makeChannelListController(channels: [existingChannel])
460+
let viewModel = ChatChannelListViewModel(
461+
channelListController: channelListController,
462+
selectedChannelId: nil
463+
)
464+
465+
// When
466+
viewModel.openChannel(with: targetChannel.cid)
467+
468+
// Then
469+
XCTAssertEqual(channelListController.loadNextChannelsCallCount, 1)
470+
471+
// Simulate first load not finding the channel
472+
channelListController.simulate(
473+
channels: [existingChannel],
474+
changes: []
475+
)
476+
477+
// Simulate second load finding the channel
478+
channelListController.simulate(
479+
channels: [existingChannel, targetChannel],
480+
changes: [.insert(targetChannel, index: .init(row: 1, section: 0))]
481+
)
482+
483+
viewModel.openChannel(with: targetChannel.cid)
484+
485+
// Verify the channel is eventually opened
486+
let expectation = XCTestExpectation(description: "Channel opened after multiple loads")
487+
DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
488+
XCTAssertEqual(viewModel.selectedChannel?.channel.id, targetChannel.id)
489+
XCTAssertNil(viewModel.scrolledChannelId)
490+
expectation.fulfill()
491+
}
492+
wait(for: [expectation], timeout: 1.0)
493+
}
494+
375495
// MARK: - private
376496

377497
private func makeChannelListController(

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