I have the following code where after a bool is true I want to add a drawing to my rect. here is the code I have but for some reason it is either not setting the bool or calling the setNeedsDisplay. Am I referencing to the other class properly? thanks
//in AppController.m
-(IBAction)colorToggle:(id)sender
{
if ([colorFilter state] == NSOnState)
{
CutoutView *theView = [[CutoutView alloc] init];
[theView setFilterEnabled:YES];
}
}
//in cutoutView.m
- (void)drawRect:(NSRect)dirtyRect
{
[[[NSColor blackColor]colorWithAlphaComponent:0.9]set];
NSRectFill(dirtyRect);
//this is what i want to be drawn when my bool is true and update the drawRect
if (filterEnabled == YES) {
NSRectFillUsingOperation(NSMakeRect(100, 100, 300, 300), NSCompositeClear);
[self update];
}
}
-(void)update
{
[self setNeedsDisplay:YES];
}
OK, you know how not every UILabel is the same? Like, you can remove one UILabel from a view without all the others disappearing too? Well, your CutoutView is the same way. When you write CutoutView *theView = [[CutoutView alloc] init]; there, that creates a new CutoutView that isn't displayed anywhere. You need to talk to your existing CutoutView (probably by hooking up an outlet, but there are any number of perfectly valid designs that will accomplish this goal).
You are forgetting to call the drawRect: method, it should looks like this:
CutoutView *theView = [[CutoutView alloc] init];
[theView setFilterEnabled:YES];
[theView setNeedsDisplay];
From the docs:
When the actual content of your view changes, it is your
responsibility to notify the system that your view needs to be
redrawn. You do this by calling your view’s setNeedsDisplay or
setNeedsDisplayInRect: method of the view.
Related
I am trying to draw something in my custom view, but not sure why drawRect could not access its instance data. Here is the steps I tried.
Create a Mac OS X app, with using storyboard checked.
In the storyboard, delete the view, then add a new custom view under the view at the same place. (I tried if the view is not deleted, same).
Assign EEGView class to the newly added custom view.
then run. From the log information, you will notice that the drawRect could not access the instance data although the instance variables get initialized and updated.
In viewCtroller.m
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
myView = [[EEGView alloc] init];
//[self.view addSubview:myView];
//Start Timer in 3 seconds to show the result.
NSTimer* _timerAppStart = [NSTimer scheduledTimerWithTimeInterval:2
target:self
selector:#selector(UpdateEEGData)
userInfo:nil
repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:_timerAppStart forMode:NSDefaultRunLoopMode];
}
- (void)UpdateEEGData
{
// NSLog(#"UpdateEEGData.....1");
// myView.aaa = 200;
// myView.nnn = [NSNumber numberWithInteger:myView.aaa];
// make sure this runs on the main thread
if (![NSThread isMainThread]) {
// NSLog(#"NOT in Main thread!");
[self performSelectorOnMainThread:#selector(updateDisplay) withObject:nil waitUntilDone:TRUE];
}else
{
[self.view setNeedsDisplay:YES];
}
NSLog(#"UpdateEEGData.....2");
[myView setAaa:400];
myView.nnn = [NSNumber numberWithInteger:myView.aaa];
// make sure this runs on the main thread
if (![NSThread isMainThread]) {
// NSLog(#"NOT in Main thread!");
[self performSelectorOnMainThread:#selector(updateDisplay) withObject:nil waitUntilDone:TRUE];
}else
{
[self.view setNeedsDisplay:YES];
}
}
-(void)updateDisplay
{
[self.view setNeedsDisplay:YES];
}
In my custom view class EEGView.m
#implementation EEGView
#synthesize aaa;
#synthesize nnn;
-(id)init{
self = [super init];
if (self) {
aaa = 10;
nnn = [NSNumber numberWithInteger:aaa];
NSLog(#"init aaa: %i", aaa);
NSLog(#"init nnn: %i", [nnn intValue]);
}
return self;
}
- (void)drawRect:(NSRect)dirtyRect {
[super drawRect:dirtyRect];
// Drawing code here.
NSLog(#"drawRect is here");
NSLog(#"drawRect aaa: %i", aaa);
NSLog(#"drawRect nnn: %i", [nnn intValue]);
}
#end
Did I miss anything? Tested in Xcode 7.2 & 7.2. But if I leave the 'using storyboard' unchecked, it works.
Or is it a Xcode bug?
Any advice appreciated.
Thanks in advance.
If you've added EEGView view on storyboard, you shouldn't be also instantiating one in viewDidLoad. You've alloc/init'ed a new one, but it bears no relationship to the one that the storyboard created for you. So, the one created by the storyboard has drawRect called, but you're setting the properties in the separate instance that you created in viewDidLoad which was never added to the view hierarchy (and thus never will have its drawRect called).
When the storyboard instantiates the view controller's view, it will instantiate your EEGView for you. All you need to do is to hook up an IBOutlet for this view in order to get a reference to it from your view controller. (For example, you can control drag from the EEGView in the storyboard scene to the #interface for the view controller that you've pulled up in the assistant editor.)
I'm trying to move a uiLabel down a drop if it's an iPhone 5 (4" display). But it's not working when the code is in viewDidLoad. If I call the code from clicking a uiButton, it works. Here's the code:
-(void) viewDidLoad {
if(CGSizeEqualToSize([[UIScreen mainScreen] preferredMode].size,CGSizeMake(640, 1136))) {
CGRect frame = [self.timeOnCurrentQuestion frame];
frame.origin.y += 40; // change the location
[self.timeOnCurrentQuestion setFrame:frame];
nslog(#"This DOES get logged");
}
}
Jonah, have you tried your code in viewWillAppear method? Possibly, it'll sort-out your issue.
Maybe that are something you need to beware of.
- (void)viewDidLoad
It is a method that when the controller juz created its view.
for example:
maybe in your init method, you call something like:
[self.view setBackground:[UIColor redColor]];
self.timeOnCurrentQuestion = [[UIView alloc] initWithFrame:kFrame];
In this case the work flow will be like this:
[self.view setBackground:[UIColor redColor]];
[self viewDidload];
self.timeOnCurrentQuestion = [[UIView alloc] initWithFrame:kFrame];
Th reason for this work flow is because the self.view is called, then its view is needed before the normal view cycle, so , in this case, self.timeOnCurrentQuestion is still nil in the viewDidload method.
I don't know if my practice is the best or not.
I always init the subView in the controller's init method.
and do the [self.view addSubview:_subview] (//or everything method call that require the self.view) in [self viewDidload];
viewDidAppear worked for me. The life cycle seems to be
LoadView()
viewDidLoad()
viewWillAppear()
viewDidAppear()
#import "DotAnimation.h"
#implementation DotAnimation
DoodlePad* dp;
-(void)setupView {
Ball = CGRectMake(10, 10, 10, 10);
[NSTimer scheduledTimerWithTimeInterval:(1.0f / 30.0f) target:self selector:#selector(traceBall) userInfo:nil repeats:YES];
}
-(id)initWithCoder:(NSCoder *)aDecoder {
if (self == [super initWithCoder:aDecoder]){
[self setupView];
}
return self;
}
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self setupView];
}
return self;
}
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.*/
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColorWithColor(context, [[UIColor yellowColor] CGColor]);
CGContextFillEllipseInRect(context, Ball);
}
-(void)traceBall{
vector<CGPoint>::iterator L = dp.doodlePoints->begin();
while(L != dp.doodlePoints->end()){
Ball.origin.x += (*L).x;
Ball.origin.y += (*L).y;
++L;
}
[self setNeedsDisplay];
}
- (void)dealloc
{
[super dealloc];
}
#end
I have this Animation I am trying to use in another file.
So i figure i do something like
trace = [[DotAnimation alloc]initWithCoder];
or
trace = [[DotAnimation alloc]initWithFrame];
I am unsure which one to use or if i am even writing this correctly.
I want to be able to use:
while(k != dp.doodlePoints->end()){
Ball.origin.x += (*k).x;
Ball.origin.y += (*k).y;
++k;
}
In another file but I don't know how to call Ball.origin from DotAnimation
Also it would be great if you could link me to good information on understanding this.
initWithCoder is called by the framework when you embed an object into a XIB. Like a ViewController for example. So you should not call it by yourself.
Calling initWithFrame could be a better solution if you want to set the frame (like that seems to be done here). But you may give a frame, and add a subview created by yourself.
if you don't want to create the subview by yourself, then it's initWithNibName:bundle: that you may call/override. Creating the XIB that contains the view. But you will still need to add that view as subview to the main view that is showing that animated view.
initWithCoder: is something you would call yourself when restoring from an archive; it isn't appropriate for something which appears to be a view object. As it is only used for simple setup code, you can remove it.
Also, animating by changing the "Ball" object from another object isn't really consistent with Cocoa view programming. You should take a look at "Introduction to View Programming Guide for Cocoa" in the documentation, and work from there.
I have an interface that has an NSTextField, NSButton, and an NSView. When I type something in the NSTextfield and press the button, I want the text to be drawn in the NSView. So far I have everything connected and working, except for the view.
How can I connect the text and the view so that every time I press the button, the text is drawn to the view?
How can I connect the text and the view so that every time I press the button, the text is drawn to the view?
Views do their own drawing.
You need to give the view the string to draw, and then set the view as needing display. You'll do these in the action method that you wire the button up to.
First, your custom view class needs to have a property for the value (string, in this case) that it's going to display. From your action method, which should generally be on a controller object, send the view object a setFoo: message (assuming you named the property foo). That takes care of job one: The view now has the value to display.
Job two is even easier: Send the view a setNeedsDisplay: message, with the value YES.
That's it. The action method is two lines.
Of course, since views draw themselves, you also need your custom view to actually draw, so you need to implement the drawRect: method in that class. It, too, will be short; all you need to do is tell the string to draw itself.
Bindings
http://developer.apple.com/mac/library/documentation/cocoa/Conceptual/CocoaBindings/Concepts/WhatAreBindings.html#//apple_ref/doc/uid/20002372-CJBEJBHH
For simplicity's sake I didn't mention this before, but the app also has a speech element to speak the string. This aspect of the program works fine, so just ignore any messages involving the SpeakAndDraw class (it's actually misnamed and only includes a speech method, nothing about drawing).
View.m
#import "View.h"
#implementation View
#synthesize stringToDraw;
- (id)initWithFrame:(NSRect)frame {
self = [super initWithFrame:frame];
if (self) {
[self setAttributes];
stringToDraw = #"Hola";
}
return self;
}
- (void)drawRect:(NSRect)dirtyRect {
NSRect bounds = [self bounds];
[self drawStringInRect:bounds];
}
- (void)setAttributes
{
attributes = [[NSMutableDictionary alloc] init];
[attributes setObject:[NSFont fontWithName:#"Helvetica"
size:75]
forKey:NSFontAttributeName];
[attributes setObject:[NSColor blackColor]
forKey:NSForegroundColorAttributeName];
}
- (void)drawStringInRect:(NSRect)rect
{
NSSize strSize = [stringToDraw sizeWithAttributes:attributes];
NSPoint strOrigin;
strOrigin.x = rect.origin.x + (rect.size.width - strSize.width)/2;
strOrigin.y = rect.origin.y + (rect.size.height - strSize.height)/2;
[stringToDraw drawAtPoint:strOrigin withAttributes:attributes];
}
#end
SpeakerController.m
#import "SpeakerController.h"
#implementation SpeakerController
- (id)init
{
speakAndDraw = [[SpeakAndDraw alloc] init];
view = [[View alloc] init];
[mainWindow setContentView:mainContentView];
[mainContentView addSubview:view];
return self;
}
- (IBAction)speakText:(id)sender
{
[speakAndDraw setStringToSay:[text stringValue]];
[speakAndDraw speak];
[view setStringToDraw:[text stringValue]];
[view setNeedsDisplay:YES];
NSLog(#"%#", view.stringToDraw);
NSLog(#"%#", [view window]);
}
#end
I'm trying to lay out some images in code using addSubview, and they are not showing up.
I created a class (myUIView) that subclasses UIView, and then changed the class of the nib file in IB to be myUIView.
Then I put in the following code, but am still getting a blank grey screen.
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
// Initialization code
[self setupSubviews];
}
return self;
}
- (void)setupSubviews
{
self.backgroundColor = [UIColor blackColor];
UIImageView *black = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"black.png"]];
black.center = self.center;
black.opaque = YES;
[self addSubview:black];
[black release];
}
yes, just implement initWithCoder.
initWithFrame is called when a UIView is created dynamically, from code.
a view that is loaded from a .nib file is always instantiated using initWithCoder, the coder takes care of reading the settings from the .nib file
i took the habit to do the initialization in a separate method, implementing both initWithCode and initWithFrame (and my own initialization methods when required)
try implementing initWithCoder: sometimes I've had trouble with IB and initWithFrame:
or at least add a logging call to see if your init method is executed