drawRect not called

[xworker]

Hi all

Very new to iphone developement, but have 10yrs as a java developer.
I have two questions about a project of mine.

First:

Trying to draw some lines on the screen.

I have a view controller in which I try to trigger the drawRect method like this:

- (void)loadView {
	NSLog(@"chartView loading");
	chartView = [[ChartView alloc] initWithFrame:CGRectMake(1.0, 0.0, 1.0, 1.0)];
	[chartView setNeedsDisplay];

the view looks like this:

#import "ChartView.h"

#import <UIKit/UIKit.h>


@implementation ChartView


- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
		NSLog(@"in init");
		
		
		    }
    return self;
}

-(void)drawRect:(CGRect)
 {
	NSLog(@"in drawRect");
    // Drawing code
	// CGContextRef context = UIGraphicsGetCurrentContext();
	 CGRect box = CGRectMake(40, 40, 240, 120);
	 CGContextSetRGBFillColor(context, 1.0,1.0,1.0,1.0);
	 CGContextFillRect(context, box);
	 
	 CGContextSetRGBStrokeColor(context, 0.0, 1.0, 0.0, 1.0);
	 CGContextStrokeRectWithWidth(context, box, 10);
	 
	
}


- (void)dealloc {
    [super dealloc];
}


@end

I see printouts of the "initWithFrame" methode being called but not the drawRect. Shouldn't drawRect be triggerd for the setNeedsDispaly call?


Question nr 2.

How do i get my view "chartView" into the IB? I read that you are supposed to be able to drag it into the window with "File Owner" and that stuff, and then it should be available. I see the green + sign when I drag it there but it doesnt show up anywhere i the library window. I want to make that view smaller and fit in on the view togheter with a few textinputs and buttons.


Thanks for your time.

/x

[Oliver Drobnik]

Originally Posted by xworker

Hi all

Very new to iphone developement, but have 10yrs as a java developer.
I have two questions about a project of mine.

First:

Trying to draw some lines on the screen.

I have a view controller in which I try to trigger the drawRect method like this:

- (void)loadView {
	NSLog(@"chartView loading");
	chartView = [[ChartView alloc] initWithFrame:CGRectMake(1.0, 0.0, 1.0, 1.0)];
	[chartView setNeedsDisplay];

the view looks like this:

#import "ChartView.h"

#import <UIKit/UIKit.h>


@implementation ChartView


- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
		NSLog(@"in init");
		
		
		    }
    return self;
}

-(void)drawRect:(CGRect)
 {
	NSLog(@"in drawRect");
    // Drawing code
	// CGContextRef context = UIGraphicsGetCurrentContext();
	 CGRect box = CGRectMake(40, 40, 240, 120);
	 CGContextSetRGBFillColor(context, 1.0,1.0,1.0,1.0);
	 CGContextFillRect(context, box);
	 
	 CGContextSetRGBStrokeColor(context, 0.0, 1.0, 0.0, 1.0);
	 CGContextStrokeRectWithWidth(context, box, 10);
	 
	
}


- (void)dealloc {
    [super dealloc];
}


@end

I see printouts of the "initWithFrame" methode being called but not the drawRect. Shouldn't drawRect be triggerd for the setNeedsDispaly call?


Question nr 2.

How do i get my view "chartView" into the IB? I read that you are supposed to be able to drag it into the window with "File Owner" and that stuff, and then it should be available. I see the green + sign when I drag it there but it doesnt show up anywhere i the library window. I want to make that view smaller and fit in on the view togheter with a few textinputs and buttons.


Thanks for your time.

/x

drawRect is send to the DELEGATE of the view. Did you set chartview.delegate?

Also, why did you create the view to be only 1 pixel wide and high?

Do you use a ViewController? Then the .view property of it needs to point to your view as well.

Question 2: Just create a new UIView from the Library and put it where you want the view to be. Then go to the rightmost tab in the inspector and change the class to be ChartView.

cheers
Oliver


Dr. Touch

[xworker]

Thanks for your answer.

How do i set the delegate? Can you show me? I thought a controller and a delegate was the same thing...

thanks for your time.

/x

[Oliver Drobnik]

Originally Posted by xworker

Thanks for your answer.

How do i set the delegate? Can you show me? I thought a controller and a delegate was the same thing...

thanks for your time.

/x

set delegate like this:


GraphView *myGraphView; // variable to hold pointer, could be in header of viewcontroller
myGraphView.delegate = self; // sets it to where you are currently

you don't need to set it to itself though, I think. Usually you would have delegate functions in the viewcontroller.

A Viewcontroller has some things that a view itself cannot do, like being pushed ontop of a navigationcontroller. Check the docs: UIViewController versus UIView. You very rarely need to subclass UIView only if you have very special drawing logic.

Unfortunately my MBP is being serviced as we speak, otherwise I would have offered that you send me the source and I find the problem for you.

cheers
Oliver

Dr. Touch

[xworker]

Originally Posted by Oliver Drobnik

set delegate like this:


GraphView *myGraphView; // variable to hold pointer, could be in header of viewcontroller
myGraphView.delegate = self; // sets it to where you are currently

you don't need to set it to itself though, I think. Usually you would have delegate functions in the viewcontroller.

A Viewcontroller has some things that a view itself cannot do, like being pushed ontop of a navigationcontroller. Check the docs: UIViewController versus UIView. You very rarely need to subclass UIView only if you have very special drawing logic.

Unfortunately my MBP is being serviced as we speak, otherwise I would have offered that you send me the source and I find the problem for you.

cheers
Oliver

Dr. Touch

Thanks!

I did set the view in my controller header file, but not the self thing.
Looks like this:

#import <UIKit/UIKit.h>
#import "ChartView.h"

@interface WeightApp2ViewController : UIViewController {

	IBOutlet UITextField *txtWeight;
	IBOutlet UITextField *txtHeight;
	IBOutlet UILabel *lblBmi;
	ChartView *chartView;
}

@property(nonatomic,retain) IBOutlet UITextField *txtWeight;
@property(nonatomic,retain) IBOutlet UITextField *txtHeight;
@property(nonatomic,retain) IBOutlet UILabel *lblBmi;

- (IBAction) calculateBmi:(id) sender;

@end

and the implementation of the controller:

#import "WeightApp2ViewController.h"

@implementation WeightApp2ViewController

@synthesize txtWeight, txtWeight, lblBmi;



- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle*)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        // Custom initialization
    }
    return self;
}



- (void)loadView {
	NSLog(@"chartView loading");
	chartView = [[ChartView alloc] initWithFrame:CGRectMake(1.0, 0.0, 1.0, 1.0)];
	[chartView setNeedsDisplay];

	
}

Gona test your solution when I get home from work

/x

[PhoneyDeveloper]

Did you add your view to the view hierarchy? It can't draw unless its a subview of something.

[xworker]

Originally Posted by PhoneyDeveloper

Did you add your view to the view hierarchy? It can't draw unless its a subview of something.

I have added like this :


#import "WeightApp2AppDelegate.h"
#import "WeightApp2ViewController.h"

@implementation WeightApp2AppDelegate

@synthesize window;
@synthesize viewController;


- (void)applicationDidFinishLaunchingUIApplication *)application {

[window addSubview:viewController.view];
[window makeKeyAndVisible];
}


- (void)dealloc {
[viewController release];
[window release];
[super dealloc];
}


@end

/x

[PhoneyDeveloper]

Remove your loadView method. Add viewDidLoad and build your chart view in viewDidLoad. Add this to viewDidLoad:

[self.view addSubView: chartView];

remove setNeedsDisplay.

also you need your chart view to be bigger than 1x1.

[PhoneyDeveloper]

Originally Posted by PhoneyDeveloper

Remove your loadView method. Add viewDidLoad and build your chart view in viewDidLoad. Add this to viewDidLoad:

[self.view addSubView: chartView];

remove setNeedsDisplay.

also you need your chart view to be bigger than 1x1.

I'm also not clear why you don't just add the chart view in IB if you're building a nib anyway.

[xworker]

Originally Posted by PhoneyDeveloper

I'm also not clear why you don't just add the chart view in IB if you're building a nib anyway.

That was the solution... Now it works. Added the view in IB and now it draws as it should.