Simple scenario - ScrollView hosting a single LinearLayout which has several children - the preferred pattern to allow a scroll enabled views in developing on Android.
I need to capture onScrollEvents, start, stop, etc. that are readily available and work very well if I use ListView/onScrollListener combination.
A dedicated widget for scrolling a view DOES NOT have the built-in capabilities to capture these events? Come On! I have tried OnTouchEvent listener, onGestureListener, etc - all work arounds and all meant for something else. What am I missing here?
Unfortunately, there is no pre-built way for getting these events. However, there are two workarounds:
Use a ListView instead
Build your own custom ScrollView with ScrollListener. This is not that hard to achieve and has been done before.
Related
What is the easiest way to implement a screen slide in Nativescript like shown in Android Viewpager , but in a vertical direction ? Another example of this functionality would be the rss reader feedly where you can change rss feeds by swiping up/down.
The page should allow vertical scrolling to the top/bottom and then transition after a certain treshold.
I already encountered nativescript-slides, which can only do horizontally sliding.
So is there a "nativescript" way or do i have to implement it as native android/ios feature (for example by this) ? In either case a sample on how to integrate it in nativescript would be great.
Update
Recorded an example:
taken from this Repo with Android native code. The outstanding PR made changes to offer vertical scrolling in the list. But the repo seems to be outdated and a bit buggy.
I can provide more info later but there's a new plugin implementing the native controls for android and iOS for slides/carousel her https://github.com/alexrainman/nativescript-carousel-view and vertical swiping is on his radar, I think he might even be close to completing that.
To give an answer for anybody interested in above nested scrolling animation:
For Android I had to implement the native ReyclerView in Nativescript in favor of the NS buildin ListView. It is an optimized view structure which among other things allows nested (vertical) scrolling and can be used as replacement for an ordinary list.
Together with https://github.com/alexrainman/nativescript-carousel-view works like a charm!
Anyone that ends up here still looking for ways to achieve this.
I spent a lot of time trying to figure out a way to achieve this and tried to find ready plugins for this. Also tried to use the plugin from Alexrainman but eventually gave up since the plugin was not up to date with the current nativescript-version.
My solution:
I used radListView as a basis for this implementation and leveraged the methods and events on the radListView.
By using scrolled-event I gathered data for the use of the scrolling feature: scroll Speed and scroll direction. (These might be also taken from the event data, but since I did not find the event details from the Nativescript-documentation I gave up trying to guess where to find this data on the event-model).
Then I also saved the fixed height of one item on my list (The height I fixed to screenHeight-200).
With all this info, I managed to hook the event "ScrollDragEnded" and add logic that makes my list behave like a vertical slider. Moving on the list by method "scrollToIndex" and figuring out which index to scroll and when by leveraging all the data mentioned above.
This is the way I managed to make a pretty good vertical slide.
Good luck!
I started out using ReactNative's RefreshControl, which worked out great at first. Now I want something more custom.
I'd like to animate an object based on the negative/overscroll scroll value, effectively what the built in RefreshControl does.
I've tried listening the the onScroll event. But it doesn't seem to fire for negative/overscroll values. I've also tried using GestureResponder, but they seem to be getting terminated.
UPDATE:
I found setting scrollEventThrottle={16} on the ScrollView gives me negative/overscroll 'onScroll' events in iOS, but doesn't seem to do anything for Android.
We have the Gallery, which support swiping.
We also have 3rd-party components that support pinch-to-zoom on ImageView, such as ImageViewTouch in ImageViewZoom.
Now I would like to combine them both.
The problem is that the swipe events get consumed by the ImageViewTouch and missed by the Gallery.
How can consume events by both components?
That would solve my problem, because, eventually, after a few events, each component will know how to react accordingly.
For example, if the first event is ACTION_DOWN, it can be part of a pinch-to-zoom or part of a swipe. Both components (Gallery and ImageViewTouch) should consume it in order to know what to do in following events.
I combined both components by changing some code in ImageViewZoom. The change was for the events to return a value if they were consumed by the ImageViewTouch. If so, than the event should not be passed to the gallery. If the event is not consumed by the ImageView, than the gallery should consume it (if it can).
There are still some small issues, but it's functional. Hopefully other people in the community can help.
Here's the fork on github: https://github.com/kilaka/ImageViewZoom
Thanks.
I'd like to make a view in my Android app that flips between multiple views on a swipe/fling. I'd like it to behave more or less like the Android Launcher behaves when flipping between views. In particular,
It should flip views on swipe.
Generally a swipe will flip between one view and the next. It should not fling across all of the views.
If you swipe slowly, you should see the views dragging as you're swiping, eg. the way the Launcher does it.
I tried using a ViewFlipper with a GestureOverlayView as per Romain Guy's blog post here, but there's no indicator to the user as they're swiping. This makes discoverability difficult, which is presumably why Launcher does it the way they do.
I tried using a Gallery object, but when I swipe from left to right, there's a certain amount of momentum that flings the users through all the views rather than just taking them to the next view.
Is there a good way to accomplish what I'm trying to do?
I know this is an old question but ViewPager is created for this exact same purpose. ViewPager is part of android compatibility package and more can be found at http://android-developers.blogspot.com/2011/08/horizontal-view-swiping-with-viewpager.html
Take a look at HorizontalPager. It's actually based on RealViewSwitcher, which in turn is based on the Android homescreen's code, and supports snap-to paging with drag feedback, as well as nested vertically-scrolling subviews. Gesture support for fast swipes isn't all it should be, but this may get you part of the way there (and I'd welcome contributions back).
EDIT: As of 2012 you're much better off using Google's ViewPager - it's in the compat library.
Check out SwipeView within this project https://github.com/fry15/uk.co.jasonfry.android.tools It does exactly what you want it to do and is super simple to implement.
#CommonsGuy extended ViewFlipper to do it.
https://github.com/commonsguy/cwac-viewswiper
Ihaven't used this one yet so im not sure if it moves with your finger like the launcher if not your going to have to make an OnTochListener to do it for you in me.ACTION_MOVE you will update the view to change its position. I'll post some sample code when I get home if you don't get another answer.
As far as I have read in the Internet and official documentation, it isn't possible to make a scrollable app widget. Also all my tries failed. I even tried to subclass TextView to implement my own scroll method, but nothing worked.
Are there any ways to achieve that?
Btw.... there are solutions if you use for example htc sense or home desktop ++, but i want to make it available to other users which don't use this
Are there any ways to achieve that?
Not directly. You can always add buttons to rotate you through various options. But true scrolling is not possible.
HTC provides scrollable app widgets because these are built-in. Only their Launcher can create and display them. Regular app widgets do not support scrolling.
As far as I have observed, app widgets are scrollable, but only in the vertical direction.
For Eg. The calendar widget is a scrollable widget which comes with mostly all android phones.
Only the vertical scrolling is allowed for the fact that horizontal scrollings are required to change the screens in the home page.
It is said only 2 gestures are allowed for a widget,
1.Touch
2.Vertical scrolling.
Source : Developer's Page
Now you can make a scrollable widget, but you'll have the problems with images within it. Workaround is described here.