How to draw a simple line without using Interface Builder? - objective-c

Question

I'm a beginner. I just want to draw a simple line without using IB .
code I used is
lineViewController.m
-(id)init
{
if(self = [super init])
{
myView = [[UIView alloc]initWithFrame:CGRectMake(0,0,320,440)];
myView.backgroundColor = [UIColor grayColor];
mView = [[UIView alloc]initWithFrame:CGRectMake(0,0,200,200)];
self.view = myView;
[myView addSubView:mView];
}
return self;
}
-(void)viewWillAppear:(BOOL)animated
{
line = [[MyView alloc]init];
[line setNeedsDisplay];
}
MyView.m
#import "MyView.h"
#implementation MyView
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
// Initialization code
}
return self;
}
- (void)drawRect:(CGRect)rect
{
CGFloat red[4] = {1.0f, 0.0f, 0.0f, 1.0f};
CGContextSetStrokeColor(c, red);
CGContextBeginPath(c);
CGContextMoveToPoint(c, 150.0f, 200.0f);
CGContextSetLineWidth(c, 5.0f);
CGContextAddLineToPoint(c, 50,300);
CGContextAddLineToPoint(c, 260,300);
CGContextClosePath(c);
}
But I'm not able to draw. Can you please help me.
Thanks in advance.

Answer 1

The code in viewWillAppear doesn't do anything because line is never added to the view hierarchy. MyView drawRect is never called because of the above and "myView" is allocated as a UIView instead of a MyView. Try changing the alloc in the view controller init.
myView = [[MyView alloc]initWithFrame:CGRectMake(0,0,320,440)];
Also the code will leak as written. Look into retain & release memory management.