GridPanel not rendering correctly
I'm using EditorGridPanels on dynamically generated web pages. ExtJS does not control the ViewPort.
When I wrap the Grid generation code in Ext.onReady(), the grids render perfectly.
If I do not wrap it in Ext.onReady() it renders with subtle layout issues like
the grids are a little too wide
the top toolbar gets cut off on the right
the rows don't quite fit and they shift when clicking a cell
I have tried forcing the grids' layout to get recalculated once the page loads...
(function(){}
var grid = ...
[ ... ]
Ext.onReady(function(){
grid.doLayout();
});
)();
...but this does not work.
The reason I'm trying to avoid placing Grid initialization inside Ext.onReady() is that sometimes pages take a long time to fully load every resource, and in these cases the pages look fully loaded apart from the blank spaces where the grids eventually get rendered to!
Any suggestions on what I might try? Right now a complete redesign of the page is not in scope, so I'm looking for something I can do to get the grid to layout like it does when initialized inside onReady()!
Thanks
You could perhaps mask the page initially with 'loading..' message and remove this in the onReady().
If you're getting issue outside of on the onReady it would indicate something has not loaded when you're trying to render components, this in my experience will lead to further issues down the line.
Related
I was wondering if there is any way to accelerate/speed up the UItableView/[reload data].
Even though I reload the data on the main thread using:
> [self.tableview performSelectorOnMainThread:#selector(reloadData) withObject:nil waitUntilDone:No]
I still think the results is quite slow (2 to 3 seconds to refresh each time the table is being reloaded, making a bad user experience if the user keep refreshing the table).
For a bit of background here is how it works at the moment.
1) I create my UITableView from data coming from the database on apple starting (until here no problem and I am fine if its taking few seconds).
2) I click on one of the item of the table view, which opens a new screen to modify the elements.
3) Once the elements is modified, I change the database of my table view so that the elements I changed comes at the top of my table view.
4) When I press the back button on the screen to change my elements, I implements the ViewWillAppear of my UITableView and I reload the data on the main thread.
5) What I observer is a latency of about 2/3 seconds to go from one screen to another. Removing the reload data line from my code, make the transition instantaneous. So the problem is really in the reload data.
Each row of my UITableView has the following elements inside:
A background color coming from a file (this is basically a gradient, the file is about 20Ko, it is a PNG, the file is store on the phone)
1 or 2 UIImageView (depending on the status of what I display) (about 5Ko each, very small PNG icons, the file is store on the phone)
3 UILabel
1 UIButton (inside this PNG, there is a picture, the original size of the picture may vary from 200 to 300ko, the original source is coming from internet. I use SDWebImage to load it/cache it)
I would think I may have too much information on each of my cell, as I can see a big difference in loading time when I only have one row, versus having 10rows.
Would like to have some input from the community to see if anything can be done to improve. The best would be to be able to update the UI in the background, so for example, when I am modifying my elements, I do reloaddata in the background, so that when I come back to the previous screen that shows the UITableView my view is already refreshed,
Thanks
Ok I foudn the solution on this website:
http://www.raywenderlich.com/31166/25-ios-app-performance-tips-tricks#drawing
20) Optimize Your Table Views
Table views need to scroll quickly — when they don’t, users really notice the lag.
To keep your table views scrolling smoothly, ensure that you’ve implemented all of the suggestions below:
Reuse cells by setting the correct reuseIdentifier.
Make as many views opaque as possible, including the cell itself.
Avoid gradients, image scaling, and offscreen drawing.
Cache the height of any rows if they aren’t always the same.
If the cell shows content that comes from the web, be sure to make those calls asynchronously and cache the responses. (Personnal note on this one as it was my issue: look at this other website http://keighl.com/post/sdwebimage-uitableviewcell/ that explains how to use SDWebImage in a UITableView. Very useful.
Use shadowPath to set up shadows.
Reduce the number of subviews.
Do as little work as possible in cellForRowAtIndexPath:. If you need to do some work, do it only once and cache the results.
Use the appropriate data structure to hold the information you need. Different structures have different costs for different operations.
Use rowHeight, sectionFooterHeight and sectionHeaderHeight to set constant heights instead of asking the delegate.
You say "A background color coming from a file" - this alerts me that you're doing IO work, which is generally time-consuming, I'm curious if you remmed out the loading a colour from a file if you get a significant speed increase?
I'm developing a custom table component for very large and very custom content. Therefore I decided not to go with TableView, but start from scratch (i.e. Control). I adopted the idea of the VirtualFlow to create and manage only the visible part of the table and reuse cells that have become invisible. However I needed virtual rows and columns.
My CustomVirtualFlow implements layoutChildren(). From the component's size and scrollbar positions I know which cells are visible. If necessary, I add cells to the VirtualFlow. I then update the content and css pseudo class states (selected, focused, ...).
This works almost fine ... currently, my only problem is that the css styles are sometimes lagging: newly created cells are shown with e.g. wrong backgrounds for a moment and then get correcteted with the next pulse.
My explanation for this is that JavaFX performs layout in two passes:
first a css pass and secondly the layout pass that calls layoutChildren().
The css of newly added children (during layoutChildren) is therefore not processes correctly.
I tried to call applyCss() directly, which helps, but seems to do too much because it takes a lot of time.
My question is:
How is the correct way to add nodes during layout, i.e. if the size of the component makes it neccessary to use further nodes?
If it is not during layoutChildren(), where else should I do it?
Is there a way to get a callback when a View appears/disappears on the screen?
I need this for analytics purposes - eg. I need to check how many times people saw a view versus how many times they clicked on it.
I can tell whether a view is on screen at a certain point in time but I'm wondering whether there is a callback for that.
Also note that I'm not interested when a View's state becomes VISIBLE and not even when a view gets rendered (because eg. in a ViewPager the Views of the second page are rendered before they actually appear on screen).
We did several workarounds for certain scenarios but I'd like to have something which is more generic. We need it in ListViews, GridViews, ScrollViews and ViewPagers and each one of them presents different challenges.
Does ViewTreeObserver.OnGlobalLayoutListener help? I have never used it myself though.
See: http://developer.android.com/reference/android/view/ViewTreeObserver.OnGlobalLayoutListener.html
One major difference that I have noticed between ExtJS 3.x and 4.x is how the rendering/layout calculation is handled for components that are rendered inside of a containing element that has display:none (NOT an Ext created/monitored containing element). In 3.x, upon showing the containing element, the Ext component it contained would be properly rendered and sized to whatever dimensions i set for it.
However, in 4.x, that same component will not be displayed at all and have a zero height and width when its containing element was shown. After it was visible if I do a call to .setSize() it would then properly be displayed. Problem is, in my application there is just no way to be able to go through all the events that could cause a hidden component to be shown, and add code to make sure its layout is manually forced to be recalculated.
So my question is, is there any way to get back 3.x's behavior in this situation for all components across the board in 4.x?
What you can try to do is set up listeners on your components that delegate to the underlying DOM elements, perhaps that will solve your issue.
However my suggestion is if at all possible is to use the framework to manage the entire page layout using Viewport. You can still suck in the HTML (if you must) and render it inside containers or panels for example. Perfect use case here is Header and Footer which are generated by server side code (jsp, gsp, asp..) and then displayed in the North or South regions of the Viewport using contentEl : 'myDivId' configuration.
I am using 5 UIWebViews in a UIScrollView to show the result of my game. Intention is to allow the user to scroll through the results screen. I had a problem where the UIWebViews won't load when scrolled to the next page. This means the first page will load successfully however when you scroll to Page 2, you will see a white blank page. Page is loaded as I can see the alert which was given in all the 5 pages, but it won't show.
I tried a workaround as mentioned here
inserting various views into UIScrollView
http://pinchzoom.com/blog/items/view/1386/one-of-the-problems-with-the-uikit-at-the-moment-is-an-issue-embedding-a-uiwebview-within-a-table
This fixed my problem, however when I submitted the app to iTunes, it got rejected with the following comment.
"3.3.1 Applications may only use Documented APIs in the manner prescribed by Apple and must not use or call any private APIs."
The non-public API that is included in your application is _documentView
I would like to fix this issue and resubmit. Can someone help please ?
Thanks
Jugs
Just use one WebView for all results (which will scroll if it doesn't fit into the screen).