NSLog with CGPoint data

Question

I have a CGPoint called point that is being assigned a touch:

UITouch *touch = [touches anyObject];

CGPoint point = [touch locationInView:self];

I want to get the x coordinate value into my console log:

NSLog(@"x: %s", point.x);

When I use this, log output for this is:

x: (null)

I have verified that point is not null when this is called using the debugger and variable watch.

Any help appreciated,

Thanks // :)

Solution 1

Actually, the real easiest way to log a CGPoint is:

NSLog(@"%@", NSStringFromCGPoint(point));

The desktop Cocoa equivalent is NSStringFromPoint().

Solution 2

point.x is a floating point number, so you should use:

NSLog(@"x: %f", point.x);

Solution 3

The simplest way to log a CGPoint value is to use the NSValue class, since it will give you all the relevant values formatted nicely for the console. It's done like so:

NSLog(@"myPoint = %@", [NSValue valueWithCGPoint:myPoint]);

You can also use the +valueWithCGRect and +valueWithCGSize methods of NSValue when you're trying to log, say, the frame (CGRect) or size (CGSize) properties of a UIView.

Solution 4

NSLog(@"point x,y: %f,%f", point.x, point.y);

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Comments

[Spanky]

This is even better. The first answer is the easiest and lightest weight way. But this gets me both x and y from the CGPoint in one set. Nice :) Great tool :)

[Jens Ayton]

Since StackOverflow saw fit to reintroduce this question in my RSS feed, I may as well pimp my general solution: jens.ayton.se/blag/almost-elegant-cave-man-debugging which allows you to go JA_DUMP(point); and get “point = { 43, 96 }” logged without having to worry about format codes.

[Dan Rosenstark]

How do I use your lib since it compiles on I386 but not on ARM? I mean, how can I work on iOS projects using it?

[Jens Ayton]

First, you’d need to build the FindAlignment.c file as an iOS app and run it on a device (not simulator). Then, copy the result into a new #elif block before the #else at line 172 in JAValueToString.m. If this doesn’t work, additional debugging will be required. I can’t do it since I’m not in the iOS programme.

[djskinner]

Also worth noting that NSStringFromCGRect() exists too.

[johndpope]

you can this helper to keep code clean #define CGLog(a) NSLog(@"%@", NSStringFromCGPoint(a))