I want to create a bar chart diagram. I already have a diagram component, I just need to adapt it to a bar chart. When touching one of the bars, the value shold pop up in small view.
As I can see there are several different strategies that can be applied here. What I want to know is which strategy should I use? Any of these or perhaps there are other better ideas?:
Bar is a UIButton.
Bar is a touch enabled UIImage.
Bar is a UIView.
Bar is just painted graphics and I have to transcode the touched coordinates and make some calculations in order to know what bar was touched. I don't don't believe in this strategy but perhaps there are reasons to rethink this that you can provide for me...
I assume that a UILable is the way to present the data associated with the bar?
Thanks in advance for your advice!
In my humble opinion, and having written many bar charts (and other charts)... #4 is actually the correct choice for performance and my personal preference. Creating the virtual graph in memory to map touches to bars is not difficult at all, as you are simply storing rectangles in arrays and checking to see if points are inside that rect.
CGRectContainsPoint(CGRect, CGPoint);
Now, having said that, if you want to introduce animations in to your chart, which is pretty cool stuff... then I could create a UIView composed of several UIViews (one for each bar, or bar segment), this way you can animate each bar individually without writing your own animation loop.
just my two cents.
my thoughts are that #2 and #3 are kind of the same since you'd display an image using a UIImageView. UIButton is a pretty thin layer on UIView that makes the event handling easy, but it might do things visually you don't want (or maybe you do?). Either way, it's so easy to try these variations I'd just play with it. I can't see a specific reason for #4 unless your overall strategy drives you in this direction, like maybe you start doing some drawing that is rich/complex enough that you have too many views being created.
AFA the popup display, it really depends what you mean by "pop up". Like once it pops up, do you need a way to dismiss that popup?
Have you checked out Core Plot? It is an active and powerful library that is pretty flexible and should meet all your needs.
Related
I am using xcode-14.2. I need to overlay like below image. Here is my image
I have tried in storyboard. But overlap the textfield. Here is the image like
The desired interface, of itself, is not difficult to achieve; our app uses it:
We do not, however, overlap two views; it just looks as if we do. The illusion is achieved by drawing.
So my first recommendation is that you use drawing, not true overlapping, to achieve the desired interface. If you insist upon using overlapping, then keep in mind that the order in the document outline at the left is back to front order. If you want the "select source account" to overlap in front of "available balance", you would need to bring the former to the front.
My app is behaving sluggishly. If i pop up a UIActionSheet, for example, instead of rolling in smoothly, it stutters in over about 5 frames. I know ideally you should have as little amount of views on screen as possible, but that's what I've got anyway.
Any suggestions for speeding it up?
EDIT:
On my view i have:
Custom navigation bar in place of the regular one. It's a UIImageView, using an image file. It has a quartzcore shadow. It contains 3 buttons. 2 of these buttons have 2 UIImages each, for normal and highlighted, generated from code when the view is shown. The other button uses an image file for normal and for highlighted.
An image file for a background lies under that. On top of the background is a UITableView. By default, it doesn't have any cells (the user adds them). We'll ignore the cell, since it's slugging regardless of their being there or not.
The header of the tableview contains some labels, and an editable uitextview. The size of the header changes as more lines are added to the textview. It also has a background image, which is transparent to allow you to see the view's background image behind it. It's loaded from a file, and a texture image on top of that is also loaded from a file.
The footer is simply a background image loaded from a file with the same texture on top.
Andrew, I'm afraid you haven't been quite specific enough to isolate the exact problem. However there are a couple of things I have picked out. Firstly, check your table view is set to be opaque. Also try to design your app so your table cells can be opaque. I'm assuming your design will allow this. You need to really know how to optimise view rendering performance if you want your table and it's cells to appear translucent over other content and it may be you would need to develop your own custom specialised alternative to UITableView if that is something you really need to know (can be done but quite advanced stuff).
Also you mention using Quartz shadow. You should be able to use UIKit for drawing shadows around images, unless you have some specialist requirement. Are you sure you need to use Quartz for what you want to do? Apologies if you already know this, but if you are fairly new to iOS development and have been looking up how to do shadows, you may have found the Quartz API's for doing that and assumed that is the solution, when (depending on what you need) you will probably be better off staying with UIKit. As a general rule of thumb, only use Quartz if you are sure you can't do what you want to do with just the UIKit API's.
Another thing to check. If you are using Quartz, then you are probably getting getting the graphics context for the UIImage view and drawing on the views context in drawRect: depending on how your view hierarchy is configured, and if you have your navigation bar view set to be transparent over the top of the UITableView, then your custom drawRect implementation may be getting called unnecessarily with every animation frame and this would be a big drain on performance.
Given the level of information you have given I'm having to guess a bit and can't give a precise answer. However for a definitive understanding of how to optimise UIView performance I recommend checking out this video (though you will need an Apple Developer account to be able to access it):
https://developer.apple.com/videos/wwdc/2011/
Session 121 – Understanding UIKit Rendering
Hope this helps. Paul.
I have an infinite scrollview in which I add images as the user scrolls. Those images have varying heights and I've been trying to come up with the best way of finding a clear space inside the current bounds of the view that would allow me to add the image view.
Is there anything built-in that would make my search more efficient?
The problem is I want the images to be sort of glued to one another with no blank space between them. Making the search through 320x480 pixels tends to be quite a CPU hog. Does anyone know an efficient method to do it?
Thanks!
It seems that you're scrolling this thing vertically (you mentioned varying image heights).
There's nothing built in to UIScrollView that will do this for you. You'll have to track your UIImageView subviews manually. You could simply maintain the max y coordinate occupied by you images as you add them.
You might consider using UITableView instead, and implementing a very customized tableView:heightForRowAtIndexPath: in your delegate. You would probably need to do something special with the actual cells as well, but it would seem to make your job a little easier.
Also, for what it's worth, you might find a way to avoid making your solution infinite. Be careful about your memory footprint! iOS will shut your app off if things get out of hand.
UPDATE
Ok, now I understand what you're going for. I had imagined that you were presenting photographs or something rectangular like that. If I were trying to cover a scroll view with UILeafs (wah wah) I would take a statistical approach. I would 'paint' leaves randomly along horizontal/vertical strips as the user scrolls. Perhaps that's what you're doing already? Whatever you're doing I think it looks good.
Now I guess that the reason you're asking is to prevent the little random white spots that show through - is that right? If I may suggest a different solution: try to color the background of your scroll view to something earthy that looks good if it shows through here and there.
Also, it occurred to me that you could use a larger template image -- something that already has a nice distribution of leaves -- with transparency all along the outside outline of the leaves but nowhere else. Then you could tile these, but with overlap, so that the alpha just shows through to the leaves below. You could have a number of these images so that it doesn't look obvious. This would take away all of the uncertainty and make your retiling very efficient.
Also, consider learning about CoreAnimation (CALayer in particular) and CoreGraphics/Quartz 2D ). Proper use of these libraries will probably yield great improvements in rendering speed.
UPDATE 2:
If your images are all 150px wide, then split your scrollview into columns and add/remove based on those (as discussed in chat).
Good luck!
I'm pretty new to iphone development, so this is more of a high-level question. The simplest description of what I am looking to do is create a zoomable/panable field on which I can place a bunch of circle objects. The number of these circles is likely to be in the hundreds, and ideally when the user zooms in close enough, more information can be displayed. From stuff I've read, it seems like UIScrollView provides the simplest way of making a zoomable/panable view but I'm not sure it's the best way to handle a view that includes a hundred graphic objects. I'm trying to figure out if I should progress further down that path or look into things like CALayers, Core Graphics, etc. Any guidance or advice would be greatly appreciated. Thanks in advance,
Roman
I suggest you to use UIScrollView, because it will save a lot of time for handling proper zooming/scrolling. So the workflow is next:
1. Zoom you scroll view
2. In delegate's callback scrollViewDidEndZooming:withView:atScale: you can obtain the scale and determine the level of detail that you need.
3. redraw the visible region (using Core Graphics) with appropriate level of detail (number of circles etc.)
So you should use the mix of Core Graphics and UIKit.
I have horizontal list for which I'm implementing my own scrolling logic. I have the "touch and drag" scrolling working great, but I'm having trouble with the "flick" gesture. All the built in scrollable views have the feature that if you "flick" the view it scrolls faster or slower based on the intensity of the flick.
Does anyone has any suggestion how do that for my view?
What I'm doing right now is changing the UIView.center.x coordinate of my custom UIView to scroll it across the screen
I would strongly suggest you figure out how to make use of the built in UIScrollView class. Apple has invested a LOT of effort to make scrolling feel 'right'. You may be able to recreate some, or even all, of that feel, but it'll take a lot of work. Better to piggy back off of what's already been done.
If you want to implement your own scroll view, you'll have to make the view scroll based on the length of the sweeping distance and the speed at witch it went across the screen. Taking these parameters as input and using simple geometry math you could calculate how much further the view should scroll after the sweep has ended(touchesEnded event).
Ofcourse this is not as simple as it sounds, making the flick gesture just feel right and natural is much harder.
If you really are set on doing this yourself, Drew McCormack has a great article on MacResearch where he explains some of the physics behind momentum-based scrolling. His implementation uses HTML, CSS, and JavaScript, but the core principles could be brought across to your custom UIView subclass.