UICollectionView scrollRectToVisible and scrollToItem break user scroll
I am using this code to reveal a specific item in a collection view.
var pages: [PDFPage]?
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
// Scroll to currently opened page
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0), at: .centeredVertically, animated: false)
}
}
It is working as expected but it completely locks user scrolling in order, I guess, to always keep the item in the requested position.
The same happens when using scrollRectToVisible.
Instead I'd like it to only move to the item, and then let the user scroll wherever he wants. Which is the behaviour I'm getting with UITableViewController's scrollToRow.
Am I missing something?
ios uicollectionview
asked Nov 16 '18 at 16:23
EdgeEdge
64
add a comment |
I am using this code to reveal a specific item in a collection view.
var pages: [PDFPage]?
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
// Scroll to currently opened page
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0), at: .centeredVertically, animated: false)
}
}
It is working as expected but it completely locks user scrolling in order, I guess, to always keep the item in the requested position.
The same happens when using scrollRectToVisible.
Instead I'd like it to only move to the item, and then let the user scroll wherever he wants. Which is the behaviour I'm getting with UITableViewController's scrollToRow.
Am I missing something?
ios uicollectionview
asked Nov 16 '18 at 16:23
EdgeEdge
64
Can you please add more context? When do you call the method? It would be great if you provide a GIF or images that illustrate your problem
– fewlinesofcode
Nov 19 '18 at 10:25
@fewlinesofcode thanks! I've updated the description with the code and a video.
– Edge
Nov 19 '18 at 21:47
add a comment |
I am using this code to reveal a specific item in a collection view.
var pages: [PDFPage]?
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
// Scroll to currently opened page
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0), at: .centeredVertically, animated: false)
}
}
It is working as expected but it completely locks user scrolling in order, I guess, to always keep the item in the requested position.
The same happens when using scrollRectToVisible.
Instead I'd like it to only move to the item, and then let the user scroll wherever he wants. Which is the behaviour I'm getting with UITableViewController's scrollToRow.
Am I missing something?
ios uicollectionview
asked Nov 16 '18 at 16:23
EdgeEdge
64
I am using this code to reveal a specific item in a collection view.
var pages: [PDFPage]?
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
// Scroll to currently opened page
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0), at: .centeredVertically, animated: false)
}
}
It is working as expected but it completely locks user scrolling in order, I guess, to always keep the item in the requested position.
The same happens when using scrollRectToVisible.
Instead I'd like it to only move to the item, and then let the user scroll wherever he wants. Which is the behaviour I'm getting with UITableViewController's scrollToRow.
Am I missing something?
ios uicollectionview
ios uicollectionview
asked Nov 16 '18 at 16:23
EdgeEdge
64
asked Nov 16 '18 at 16:23
EdgeEdge
64
edited Nov 20 '18 at 22:22
Edge
asked Nov 16 '18 at 16:23
EdgeEdge
64
asked Nov 16 '18 at 16:23
EdgeEdge
64
asked Nov 16 '18 at 16:23
EdgeEdge
64
64
Can you please add more context? When do you call the method? It would be great if you provide a GIF or images that illustrate your problem
– fewlinesofcode
Nov 19 '18 at 10:25
@fewlinesofcode thanks! I've updated the description with the code and a video.
– Edge
Nov 19 '18 at 21:47
add a comment |
Can you please add more context? When do you call the method? It would be great if you provide a GIF or images that illustrate your problem
– fewlinesofcode
Nov 19 '18 at 10:25
@fewlinesofcode thanks! I've updated the description with the code and a video.
– Edge
Nov 19 '18 at 21:47
Can you please add more context? When do you call the method? It would be great if you provide a GIF or images that illustrate your problem
– fewlinesofcode
Nov 19 '18 at 10:25
Can you please add more context? When do you call the method? It would be great if you provide a GIF or images that illustrate your problem
– fewlinesofcode
Nov 19 '18 at 10:25
@fewlinesofcode thanks! I've updated the description with the code and a video.
– Edge
Nov 19 '18 at 21:47
@fewlinesofcode thanks! I've updated the description with the code and a video.
– Edge
Nov 19 '18 at 21:47
add a comment |
1 Answer
1
active
oldest
votes
Turns out calling the scroll in viewDidLayoutSubviews was the issue, because it was continuously repeated and preventing any further scroll. I solved the issue like this:
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Scroll to currently opened outline
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0),
at: .top,
animated: false)
// In order to only run the scroll once, without locking the view
currentPage = nil
}
}
answered Nov 20 '18 at 22:23
EdgeEdge
64
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53341793%2fuicollectionview-scrollrecttovisible-and-scrolltoitem-break-user-scroll%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Turns out calling the scroll in viewDidLayoutSubviews was the issue, because it was continuously repeated and preventing any further scroll. I solved the issue like this:
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Scroll to currently opened outline
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0),
at: .top,
animated: false)
// In order to only run the scroll once, without locking the view
currentPage = nil
}
}
answered Nov 20 '18 at 22:23
EdgeEdge
64
add a comment |
Turns out calling the scroll in viewDidLayoutSubviews was the issue, because it was continuously repeated and preventing any further scroll. I solved the issue like this:
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Scroll to currently opened outline
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0),
at: .top,
animated: false)
// In order to only run the scroll once, without locking the view
currentPage = nil
}
}
answered Nov 20 '18 at 22:23
EdgeEdge
64
add a comment |
Turns out calling the scroll in viewDidLayoutSubviews was the issue, because it was continuously repeated and preventing any further scroll. I solved the issue like this:
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Scroll to currently opened outline
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0),
at: .top,
animated: false)
// In order to only run the scroll once, without locking the view
currentPage = nil
}
}
answered Nov 20 '18 at 22:23
EdgeEdge
64
Turns out calling the scroll in viewDidLayoutSubviews was the issue, because it was continuously repeated and preventing any further scroll. I solved the issue like this:
var currentPage: PDFPage?
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// Scroll to currently opened outline
if let current = currentPage, let idx = pages?.firstIndex(of: current) {
collectionView?.scrollToItem(at: IndexPath(item: idx, section: 0),
at: .top,
animated: false)
// In order to only run the scroll once, without locking the view
currentPage = nil
}
}
answered Nov 20 '18 at 22:23
EdgeEdge
64
answered Nov 20 '18 at 22:23
EdgeEdge
64
answered Nov 20 '18 at 22:23
EdgeEdge
64
answered Nov 20 '18 at 22:23
EdgeEdge
64
64
add a comment |
add a comment |
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53341793%2fuicollectionview-scrollrecttovisible-and-scrolltoitem-break-user-scroll%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Can you please add more context? When do you call the method? It would be great if you provide a GIF or images that illustrate your problem
– fewlinesofcode
Nov 19 '18 at 10:25
@fewlinesofcode thanks! I've updated the description with the code and a video.
– Edge
Nov 19 '18 at 21:47