I’m trying to implement this code for accelerometer use, but I’m getting a compiler error:
stray /342, stray/200, stray/223 … for size,currentTouch, position object’s and so on …
Why?
Code
File GravityObj.h
@interface GravityObj : UIView {
CGPoint position;
CGSize size;
CGPoint velocity;
NSTimer *objTimer;
NSString *pngName;
CGFloat bounce;
CGFloat gravity;
CGPoint acceleratedGravity;
CGPoint lastTouch;
CGPoint currentTouch;
BOOL dragging;
}
@property CGPoint position;
@property CGSize size;
@property CGPoint velocity;
@property(nonatomic,retain)NSString *pngName;
@property(nonatomic,retain)NSTimer *objTimer;
@property CGFloat bounce;
@property CGFloat gravity;
@property CGPoint acceleratedGravity;
@property CGPoint lastTouch;
@property CGPoint currentTouch;
@property BOOL dragging;
- (id)initWithPNG:(NSString*)imageName position:(CGPoint)p size:(CGSize)s;
- (void)update;
- (void)onTimer;
@end
File GravityObj.m
#import "GravityObj.h"
@implementation GravityObj
@synthesize position, size;
@synthesize objTimer;
@synthesize velocity;
@synthesize pngName;
@synthesize bounce;
@synthesize gravity, acceleratedGravity;
@synthesize lastTouch, currentTouch;
@synthesize dragging;
- (id)initWithPNG:(NSString*)imageName position:(CGPoint)p size:(CGSize)s {
if (self = [super initWithFrame:CGRectMake(p.x, p.y, s.width, s.height)]) {
[self setPngName:imageName];
[self setPosition:p];
[self setSize:s];
[self setBackgroundColor:[UIColor clearColor]];
// Set default gravity and bounce
[self setBounce:-0.9f];
[self setGravity:0.5f];
[self setAcceleratedGravity:CGPointMake(0.0, gravity)];
[self setDragging:NO];
UIImageView *prezzie = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, s.width, s.height)];
prezzie.image = [UIImage imageNamed:imageName];
[self addSubview:prezzie];
[prezzie release];
[[UIAccelerometer sharedAccelerometer] setDelegate:self];
}
return self;
}
- (void)update {
[self setNeedsDisplay];
if(dragging)
return;
velocity.x += acceleratedGravity.x;
velocity.y += acceleratedGravity.y;
position.x += velocity.x;
position.y += velocity.y;
if(position.x + size.width >= 320.0) {
position.x = 320.0 – size.width;
velocity.x *= bounce;
}
else if(position.x <= 0.0) {
velocity.x *= bounce;
}
if(position.y + size.height >= 416.0) {
position.y = 416.0 – size.height;
velocity.y *= bounce;
}
else if(position.y <= 0.0) {
velocity.y *= bounce;
}
self.frame = CGRectMake(position.x, position.y, size.width, size.height);
}
- (void)onTimer {
[self update];
}
- (void)drawRect:(CGRect)rect {
// Drawing code
}
/* EVENTS */
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
acceleratedGravity.x = acceleration.x * gravity;
acceleratedGravity.y = -acceleration.y * gravity;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
// First, let's check to make sure the timer has been initiated
if (objTimer == nil) {
objTimer = [NSTimer scheduledTimerWithTimeInterval:1.0 / 30.0 target:self selector:@selector(onTimer) userInfo:nil repeats:YES];
}
UITouch *touch = [touches anyObject];
[self setCurrentTouch:[touch locationInView:self]];
CGFloat dx = currentTouch.x – position.x;
CGFloat dy = currentTouch.y – position.y;
CGFloat dist = sqrt(dx * dx + dy * dy);
if(dist < size.width) {
[self setVelocity:CGPointMake(0.0, 0.0)];
[self setDragging:YES];
}
[self setLastTouch:currentTouch];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
[self setCurrentTouch:[touch locationInView:self]];
[self setDragging:YES];
[self setVelocity:CGPointMake(currentTouch.x – lastTouch.x, currentTouch.y – lastTouch.y)];
[self setLastTouch:currentTouch];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[self setDragging:NO];
}
- (void)dealloc {
[objTimer release], objTimer = nil;
[pngName release], pngName = nil;
[super dealloc];
}
@end
It looks like the minus signs in some of your lines were Unicode characters that display as minuses and aren’t. I copied your code into Xcode and got the same error. I then retyped each line that had the error and it worked.
Here’s the fixed version (.m file only):
If you get that error again, I found that viewing the file in FileMerge can help; it doesn’t seem to know Unicode as well as Xcode.