i want to split the view into three different parts.each part i want to set different color.
i have tried using drawing methods in drawrect.i've succeded but the splitting should be done on button click.
here is the code that i have used.
-(void)drawRect:(CGRect)rect
{
int i=0;
float width =rect.size.width/[elements count];
CGRect paintRect;
for (NSString *color in self.elements)
{
paintRect = CGRectMake(rect.origin.x+(i*width), rect.origin.y, width, rect.size.height);
i++;
UIColor *colorr=[UIColor colorWithHexString:color];
[colorr set];
UIRectFill(paintRect);
}
}
enter code here
now i want to use this code on button click.....
help...thanx in advanced
a much easier way to do this would be to put three custom buttons or custom views and arrange them in code.
Put the backcolor of the button or view to the selections you want.
And in the case of button you attach the UIControlEventTouchUpInside event and trap the touch.
in the case of a view. you would subclass the view and override the touch events associated to that view and build your own "click" event
This is a lot less complicated than trying to create your own touch locations in a single view.
Another option would be to grab the color at the pixel that is touched. there are a lot of examples of this on stackoverflow. here is one
Hope that helps
Related
I have a UIPopover that shows up a plain view containing a UITextView filled with some text. I have managed to highlight the text. When the popover is dismissed, and re-opened, the highlight disappears. I want to keep the text highlighted even if if the application is closed. Any ideas how to achieve that?The code i used is the following :
- (void)highlight {
NSRange selectedRange = self.textViewAll.selectedRange;
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]
initWithAttributedString:self.textViewAll.attributedText];
[attributedString addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:selectedRange];
// [highlightedRange addObject:];
// This is where i tried to save each location and length in a mutable array but didn't work
[highlightedRangeLocation insertObject:[NSNumber numberWithInteger:selectedRange.location] atIndex:indexOfHighlight];
[highlightedRangeLength insertObject:[NSNumber numberWithInteger:selectedRange.length] atIndex:indexOfHighlight];
///////////////////////////////////////////////////////////////////////////////
self.textViewAll.attributedText = attributedString;
indexOfHighlight ++ ;
}
- (void)viewDidLoad {
UIMenuItem *highlightMenuItem = [[UIMenuItem alloc] initWithTitle:#"Highlight" action:#selector(highlight)];
[[UIMenuController sharedMenuController] setMenuItems:[NSArray arrayWithObject:highlightMenuItem]];
float sysVer = [[[UIDevice currentDevice] systemVersion] floatValue];
if (sysVer >= 8.0) {
self.textViewAll.layoutManager.allowsNonContiguousLayout = NO;
}
}
Could anyone point out how to continue from here?
Edit 1 :
The code that close the popover :
- (IBAction)closeFun:(id)sender {
// self.popoverPresentationController set
[self dismissViewControllerAnimated:YES completion:nil];
// [self dismis]
}
Can't you juste save the Highlighted text range in [NSUserDefaults standardUserDefaults] whenever the popover is dismissed, and retrieve it when the popover reappears ?
I think the problem is in the fact that the popover is responsible for the highlighted state, i.e .it is the popover who keeps that fact/state.
The popover is a part of presentation layer / user interface. Surely the highlight represents some fact that ( now comes the catch ) - is completely independent of the popover.
For example highlighting a task could represent that the task is due. Or, highlighting a label to red color could mean that the balance in the bank is in negative numbers.
You see, no matter what user interface element you use, they only represent some underlying business reality.
But what probably happens you create a popover instance, you set it to have a highlighted element. But then this concrete popover instance dies, when it is closed.
And the highlight dies with it.
When you click some button (I guess), a popover shows up, but it is a different instance. This instance doesn't know about highlight.
Even if you somehow managed to keep the one instance of popover alive, and just hide and show it again, the popover should NOT be responsible to know whether something is red or due, (and thus highlighted.)
In you application, you should have a well separated model layer...which is basically a set of related objects that represent state ie. fact that are related to what the application solves from business perspective (for ex. draws lines, calculates interest..stores music..anything really). This model layer, some object in it, should store the facts..ie.e. the task is due, or the balance is low.
Every time you show your popover, you should investigate what are the underlying facts in your model layer right when the popover is being shown. Ivestigating means find a programmatic way to look into model objects, find out about values there and and set up the highlight in that moment again based on this "investigation". You should not rely on the fact that it was highlighted in the not so distant past.
I'm trying to put a string in a rectangular form via drawInRect:withAttributes: method. The official documentation writes: "Draws the receiver with the font and other display characteristics of the given attributes, within the specified rectangle in the currently focused UIView."
This action should be done on a button event. But it doesn't work at all. Nothing is shown.
The code that I use:
- (IBAction)buttonPressed:(id)sender
{
// some area on the top (a part of UIView)
CGRect rect = CGRectMake(50, 50, 100, 100);
// my text
NSString *str = #"Eh, what's wrong with this code?";
// crappy attributes
NSDictionary *attributes = #{NSFontAttributeName: [UIFont boldSystemFontOfSize:8]};
// and finally passing a message
[str drawInRect:rect withAttributes:attributes];
}
Is there a particular kind of areas that might be used for drawing strings in rects? Or is it possible to draw a string in a rect where I'd like it to be? Please, help me understand it better!
But it doesn't work at all. Nothing is shown.
That's because no drawing context is set up when you run that code. You're looking at drawing as something that you can do whenever you feel like it, but in fact drawing is something that you should only do when the system asks you to. At other times, you should instead remember what you want to draw, and then draw it when the time comes.
When is "the time" to draw? It's when your view's -drawRect: method is called. Since your method is an action, it looks like you're probably trying to do the drawing in a view controller. What you want to do instead is to subclass UIView and override -drawRect: to draw what you want.
It doesn't work that way, you first need to make a CGContextRef where you will draw the text.
Your code is fine, just place everything within drawRect.
I'm trying to increase the scrolling performance of my UIScrollView. I have a lot of UIButtons on it (they could be hundreds): every button has a png image set as background.
If I try to load the entire scroll when it appears, it takes too much time. Searching on the web, I've found a way to optimize it (loading and unloading pages while scrolling), but there's a little pause in scrolling everytime I have to load a new page.
Do you have any advice to make it scroll smoothly?
Below you can find my code.
- (void)scrollViewDidScroll:(UIScrollView *)tmpScrollView {
CGPoint offset = tmpScrollView.contentOffset;
//322 is the height of 2*2 buttons (a page for me)
int currentPage=(int)(offset.y / 322.0f);
if(lastContentOffset>offset.y){
pageToRemove = currentPage+3;
pageToAdd = currentPage-3;
}
else{
pageToRemove = currentPage-3;
pageToAdd = currentPage+3;
}
//remove the buttons outside the range of the visible pages
if(pageToRemove>=0 && pageToRemove<=numberOfPages && currentPage<=numberOfPages){
for (UIView *view in scrollView.subviews)
{
if ([view isKindOfClass:[UIButton class]]){
if(lastContentOffset<offset.y && view.frame.origin.y<pageToRemove*322){
[view removeFromSuperview];
}
else if(lastContentOffset>offset.y && view.frame.origin.y>pageToRemove*322){
[view removeFromSuperview];
}
}
}
}
if(((lastContentOffset<offset.y && lastPageToAdd+1==pageToAdd) || (lastContentOffset>offset.y && lastPageToAdd-1==pageToAdd)) && pageToAdd>=0 && pageToAdd<=numberOfPages){
int tmpPage=0;
if((lastContentOffset<offset.y && lastPageToAdd+1==pageToAdd)){
tmpPage=pageToAdd-1;
}
else{
tmpPage=pageToAdd;
}
//the images are inside the application folder
NSString *docDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
for(int i=0;i<4;i++){
UIButton* addButton=[[UIButton alloc] init];
addButton.layer.cornerRadius=10.0;
if(i + (tmpPage*4)<[imagesCatalogList count]){
UIImage* image=[UIImage imageWithContentsOfFile:[NSString stringWithFormat: #"%#/%#",docDir,[imagesCatalogList objectAtIndex:i + (tmpPage*4)]]];
if(image.size.width>image.size.height){
image=[image scaleToSize:CGSizeMake(image.size.width/(image.size.height/200), 200.0)];
CGImageRef ref = CGImageCreateWithImageInRect(image.CGImage, CGRectMake((image.size.width-159.5)/2,(image.size.height-159.5)/2, 159.5, 159.5));
image = [UIImage imageWithCGImage:ref];
}
else if(image.size.width<image.size.height){
image=[image scaleToSize:CGSizeMake(200.0, image.size.height/(image.size.width/200))];
CGImageRef ref = CGImageCreateWithImageInRect(image.CGImage, CGRectMake((image.size.width-159.5)/2, (image.size.height-159.5)/2, 159.5, 159.5));
image = [UIImage imageWithCGImage:ref];
}
else{
image=[image scaleToSize:CGSizeMake(159.5, 159.5)];
}
[addButton setBackgroundImage:image forState:UIControlStateNormal];
image=nil;
addButton.frame=CGRectMake(width, height, 159.5, 159.5);
NSLog(#"width %i height %i", width, height);
addButton.tag=i + (tmpPage*4);
[addButton addTarget:self action:#selector(modifyImage:) forControlEvents:UIControlEventTouchUpInside];
[tmpScrollView addSubview:addButton];
addButton=nil;
photos++;
}
}
}
lastPageToAdd=pageToAdd;
lastContentOffset=offset.y;
}
Here's a few recommendations:
1) First, understand that scrollViewDidScroll: will get called continuously, as the user scrolls. Not just once per page. So, I would make sure that you have logic that ensures that the real work involved in your loading is only triggered once per page.
Typically, I will keep a class ivar like int lastPage. Then, as scrollViewDidScroll: is called, I calculate the new current page. Only if it differs from the ivar do I trigger loading. Of course, then you need to save the dynamically calculated index (currentPage in your code) in your ivar.
2) The other thing is that I try not to do all the intensive work in the scrollViewDidScroll: method. I only trigger it there.
So, for example, if you take most of the code you posted and put it in a method called loadAndReleasePages, then you could do this in the scrollViewDidScroll: method, which defers the execution until after scrollViewDidScroll: finishes:
- (void)scrollViewDidScroll:(UIScrollView *)tmpScrollView {
CGPoint offset = tmpScrollView.contentOffset;
//322 is the height of 2*2 buttons (a page for me)
int currentPage = (int)(offset.y / 322.0f);
if (currentPage != lastPage) {
lastPage = currentPage;
// we've changed pages, so load and release new content ...
// defer execution to keep scrolling responsive
[self performSelector: #selector(loadAndReleasePages) withObject: nil afterDelay:0];
}
}
This is code that I've used since early iOS versions, so you can certainly replace the performSelector: call with an asynchronous GCD method call, too. The point is not to do it inside the scroll view delegate callback.
3) Finally, you might want to experiment with slightly different algorithms for calculating when the scroll view has actually scrolled far enough that you want to load and release content. You currently use:
int currentPage=(int)(offset.y / 322.0f);
which will yield integer page numbers based on the way the / operator, and the float to int cast works. That may be fine. However, you might find that you want a slightly different algorithm, to trigger the loading at a slightly different point. For example, you might want to trigger the content load as the page has scrolled exactly 50% from one page to the next. Or you might want to trigger it only when you're almost completely off the first page (maybe 90%).
I believe that one scrolling intensive app I wrote actually did require me to tune the precise moment in the page scroll when I did the heavy resource loading. So, I used a slightly different rounding function to determine when the current page has changed.
You might play around with that, too.
Edit: after looking at your code a little more, I also see that the work you're doing is loading and scaling images. This is actually also a candidate for a background thread. You can load the UIImage from the filesystem, and do your scaling, on the background thread, and use GCD to finally set the button's background image (to the loaded image) and change its frame back on the UI thread.
UIImage is safe to use in background threads since iOS 4.0.
Don't touch a line of code until you've profiled. Xcode includes excellent tools for exactly this purpose.
First, in Xcode, make sure you are building to a real device, not the simulator
In Xcode, choose Profile from the Product menu
Once Instruments opens, choose the Core Animation instrument
In your app, scroll around in the scroll view you're looking to profile
You'll see the real time FPS at the top, and in the bottom, you'll see a breakdown of all function and method calls based on total time ran. Start drilling down the highest times until you hit methods in your own code. Hit Command + E to see the panel on the right, which will show you full stack traces for each function and method call you click on.
Now all you have to do is eliminate or optimize the calls to the most "expensive" functions and methods and verify your higher FPS.
That way you don't waste time optimizing blind, and potentially making changes that have no real effect on the performance.
My answer is really a more general approach to improving scroll view and table view performance. To address some of your particular concerns, I highly recommend watching this WWDC video on advanced scroll view use: https://developer.apple.com/videos/wwdc/2011/includes/advanced-scrollview-techniques.html#advanced-scrollview-techniques
The line that is likely killing your performance is:
addButton.layer.cornerRadius=10.0;
Why? Turns out the performance for cornerRadius is AWFUL! Take it out... guaranteed huge speedup.
Edit: This answer sums up what you should do quite clearly.
https://stackoverflow.com/a/6254531/537213
My most common solution is to rasterize the Views:
_backgroundView.layer.shouldRasterize = YES;
_backgroundView.layer.rasterizationScale = [[UIScreen mainScreen] scale];
But it works not in every situation.. Just try it
I have implemented a custom split view controller which — in principle — works quite well.
There is, however one aspect that does not work was expected and that is the resize-animation of the toolbar on iOS prior to version 5.1 — if present:
After subclassing UIToolbar to override its layoutSubviews method, animating changes to the width of my main-content area causes the toolbar-items to move as expected. The background of the toolbar — however — does not animate as expected.
Instead, its width changes to the new value immediately, causing the background to be shown while increasing the width.
Here are what I deem the relevant parts of the code I use — all pretty standard stuff, as little magic/hackery as possible:
// From the implementation of my Split Layout View Class:
- (void)setAuxiliaryViewHidden:(BOOL)hide animated:(BOOL)animated completion:(void (^)(BOOL isFinished))completion
{
auxiliaryViewHidden_ = hide;
if (!animated)
{
[self layoutSubviews];
if (completion)
completion(YES);
return;
}
// I've tried it with and without UIViewAnimationOptionsLayoutSubviews -- didn't change anything...
UIViewAnimationOptions easedRelayoutStartingFromCurrentState = UIViewAnimationOptionCurveEaseOut | UIViewAnimationOptionBeginFromCurrentState;
[UIView animateWithDuration:M_1_PI delay:0.0 options:easedRelayoutStartingFromCurrentState animations:^{
[self layoutSubviews];
} completion:completion];
}
- (void)layoutSubviews
{
[super layoutSubviews];
// tedious layout work to calculate the frames for the main- and auxiliary-content views
self.mainContentView.frame = mainContentFrame; // <= This currently has the toolbar, but...
self.auxiliaryContentView.frame = auxiliaryContentFrame; // ...this one could contain one, as well.
}
// The complete implementation of my UIToolbar class:
#implementation AnimatableToolbar
static CGFloat sThresholdSelectorMargin = 30.;
- (void)layoutSubviews
{
[super layoutSubviews];
// walk the subviews looking for the views that represent toolbar items
for (UIView *subview in self.subviews)
{
NSString *className = NSStringFromClass([subview class]);
if (![className hasPrefix:#"UIToolbar"]) // not a toolbar item view
continue;
if (![subview isKindOfClass:[UIControl class]]) // some other private class we don't want to f**k around with…
continue;
CGRect frame = [subview frame];
BOOL isLeftmostItem = frame.origin.x <= sThresholdSelectorMargin;
if (isLeftmostItem)
{
subview.autoresizingMask = UIViewAutoresizingFlexibleRightMargin;
continue;
}
BOOL isRightmostItem = (CGRectGetMaxX(self.bounds) - CGRectGetMaxX(frame)) <= sThresholdSelectorMargin;
if (!isRightmostItem)
{
subview.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin;
continue;
}
subview.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
}
}
#end
I’ve set the class of the toolbar in InterfaceBuilder and I know for a fact, that this code gets called and, like I said, on iOS 5.1 everything works just fine.
I have to support iOS starting version 4.2, though…
Any help/hints as to what I’m missing are greatly appreciated.
As far as I can see, your approach can only work on iOS SDK > 5. Indeed, iOS SDK 5 introduced the possibility of manipulating the UIToolbar background in an explicit way (see setBackgroundImage:forToolbarPosition:barMetrics and relative getter method).
In iOS SDK 4, an UIToolbar object has no _UIToolbarBackground subview, so you cannot move it around in your layoutSubviews implementation. To verify this, add a trace like this:
for (UIView *subview in self.subviews)
{
NSLog(#"FOUND SUBVIEW: %#", [subview description]);
run the code on both iOS 4 and 5 and you will see what I mean.
All in all, the solution to your problem lays in handling the background in two different ways under iOS 4 and iOS 5. Specifically, on iOS 4 you might give the following approach a try:
add a subview to your custom UIToolbar that acts as a background view:
[toolbar insertSubview:backgroundView atIndex:0];
set:
toolbar.backgroundColor = [UIColor clearColor];
so that the UIToolbar background color does not interfere;
in your layoutSubviews method animate around this background subview together with the others, like you are doing;
Of course, nothing prevents you from using this same background subview also for iOS 5, only thing you should beware is that at step 1, the subview should be inserted at index 1 (i.e, on top of the existing background).
Hope that this helps.
Since I think this is going to be useful for someone else, I’ll just drop my solution here for reference:
Per sergio’s suggestion, I inserted an additional UIImageView into the view hierarchy. But since I wanted this to work with the default toolbar styling, I needed to jump trough a few hoops:
The image needed to be dynamically generated whenever the tintColor changed.
On iOS 5.0.x the toolbar background is an additional view.
To resolve this I ended up…
Implementing +load to set a static BOOL on whether I need to do anything. (Parses -[UIDevice systemVersion] for version prior to 5.1).
Adding a (lazily loaded) property for the image view stretchableBackground. The view will be nilif my static flag is NO. Otherwise the view will be created having twice the width of [UIScreen mainScreen], offset to the left by half that width and resizable in height and right margin and inserted into the toolbar at index 0.
Overriding setTintColor:. Whenever this happens, I call through to super and __updateBackground.
Implemented a method __updateBackground that:
When the toolbar responds to backgroundImageForToolbarPosition:barMetrics: get the first subview that is not our stretchableBackground. Use the contents property of that view’s layer to populate the stretchableBackground’s image property and return.
If the toolbar doesn’t respond to that selector,
use CGBitmapContextCreate() to obtain a 32bit RGBA CGContextRef that is one pixel wide and as high as the toolbar multiplied by the screen’s scale. (Use kCGImageAlphaPremultipliedLast to work with the device RGB color space…)
Translate the CTM by that height and scale it by scale/-scale to transition from UIKit to CG-Coordinates and draw the view’s layer into that context. (If you fail to do this, your image will always be transparent blank…)
Create a UIImage from that context and set it as the stretchableBackground’s image.
Notice that this fix for iOS 5.0.x will not work as expected when using different background images for portrait and landscape or images that do not scale — although that can be tweaked by configuring the image view differently…
i am still very new to objective c and in fact this is my first attempt to build an app so please bear with me...
I am trying to add an UITable beside core-plot graph, i have taken CPTestApp example and stated to work off that, i was able to get the graph part working ok but i am having trouble with UITable. Below is the screenshot of how it look at the moment.UITable is upside down and the text is all mirrored..
below is rotation part, can someone point me with an example for UITable rotation together with graph...UITable is populated with an array of values and that is working ok too..
i probably need some guidance to figure out the correct way to add UItable to the coreplothosting view layer
Thanks
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
if (UIInterfaceOrientationIsLandscape(fromInterfaceOrientation))
{
// Move the plots into place for portrait
scatterPlotView.frame = CGRectMake(20.0f, 55.0f, 728.0f, 556.0f);
tblSimpleTable.frame = CGRectMake(20.0f, 644.0f, 728.0f, 340.0f);
[tblSimpleTable reloadData];
}
else
{
// Move the plots into place for landscape
scatterPlotView.frame = CGRectMake(20.0f, 55.0f, 858.0f, 677.0f);
tblSimpleTable.frame = CGRectMake(878.0f, 51.0f, 220.0f, 677.0f);
[tblSimpleTable reloadData];
}
}
Core Plot applies a flip transform to all of its Core Animation layers so that the drawing code can be shared between iOS and MacOS. This is what you're seeing.
Make sure your UITable and graph hosting view are siblings (i.e., have a common parent view) and one is not a subview of the other.