手势与触摸

如果要VIEW支持用户交互，得要设置

 

self.userInteractionEnabled = YES;

 一个简单的UIView例子

 

@interface DragView : UIImageView
{
	CGPoint startLocation;
}
@end

@implementation DragView
- (id) initWithImage: (UIImage *) anImage
{
	if (self = [super initWithImage:anImage])
		self.userInteractionEnabled = YES;
	return self;
}

- (void) touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event
{
	// Calculate and store offset, and pop view into front if needed
	CGPoint pt = [[touches anyObject] locationInView:self];
	startLocation = pt;
	[[self superview] bringSubviewToFront:self];
	NSLog(@"begin");
}

- (void) touchesMoved:(NSSet*)touches withEvent:(UIEvent*)event
{
	// Calculate offset
	CGPoint pt = [[touches anyObject] locationInView:self];

	float dx = pt.x - startLocation.x;
	float dy = pt.y - startLocation.y;
	CGPoint newcenter = CGPointMake(self.center.x + dx, self.center.y + dy);
	// Bound movement into parent bounds
	float halfx = CGRectGetMidX(self.bounds);
	newcenter.x = MAX(halfx, newcenter.x);
	newcenter.x = MIN(self.superview.bounds.size.width - halfx, newcenter.x);

	float halfy = CGRectGetMidY(self.bounds);
	newcenter.y = MAX(halfy, newcenter.y);
	newcenter.y = MIN(self.superview.bounds.size.height - halfy, newcenter.y);

	// Set new location
	self.center = newcenter;
}
@end

 手动创建一图片的UIImageView

 

- (UIImage *) createImage
{
	UIColor *color = [UIColor colorWithRed:RANDLEVEL green:RANDLEVEL blue:RANDLEVEL alpha:1.0f];
        //设置图片的区域
	UIGraphicsBeginImageContext(CGSizeMake(SIDELENGTH, SIDELENGTH));
	CGContextRef context = UIGraphicsGetCurrentContext();
	
	// Create a filled ellipse  填充区域
	[color setFill];
	CGRect rect = CGRectMake(0.0f, 0.0f, SIDELENGTH, SIDELENGTH);
	CGContextAddEllipseInRect(context, rect);
	CGContextFillPath(context);
	
	// Outline the circle a couple of times
	CGContextSetStrokeColorWithColor(context, [[UIColor whiteColor] CGColor]);
	CGContextAddEllipseInRect(context, CGRectInset(rect, INSET_AMT, INSET_AMT));
	CGContextStrokePath(context);
	CGContextAddEllipseInRect(context, CGRectInset(rect, 2*INSET_AMT, 2*INSET_AMT));
	CGContextStrokePath(context);
	
	UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
	UIGraphicsEndImageContext();
	return theImage;
}

 

判断是否在区域里面 HALFSIDE是圆的半径

 

- (BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event 
{
	CGPoint pt;
	float HALFSIDE = SIDELENGTH / 2.0f;
	
	// normalize with centered origin
	pt.x = (point.x - HALFSIDE) / HALFSIDE;
	pt.y = (point.y - HALFSIDE) / HALFSIDE;
	
	// x^2 + y^2 = radius
	float xsquared = pt.x * pt.x;
	float ysquared = pt.y * pt.y;
	
	// If the radius < 1, the point is within the clipped circle
	if ((xsquared + ysquared) < 1.0) return YES;
	return NO;
}

根据图像的像位判断是否点击到图片，位图上面的触摸

 

- (BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event 
{
        //如果点下去的点不在self.bounds里面直接返回NO
	if (!CGRectContainsPoint(self.bounds, point)) {
		return NO;
	}
        //如果这个点的中断值 ALPHA小于33%,就可以看做是透明了，但也要和实际情况
	return (bytes[alphaOffset(point.x, point.y, self.image.size.width)] > 85);
}
//计算当前点在数像中的位的位置
//X，Y表示点的坐标，W表示当前VIEW的宽度
NSUInteger alphaOffset(NSUInteger x, NSUInteger y, NSUInteger w){
	return y * w * 4 + x * 4 + 0;
}

//计算图像的位
unsigned char *getBitmapFromImage (UIImage *image)
{
	
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	if (colorSpace == NULL)
    {
        fprintf(stderr, "Error allocating color space\n");
        return NULL;
    }
	
	CGSize size = image.size;
	// void *bitmapData = malloc(size.width * size.height * 4);
	unsigned char *bitmapData = calloc(size.width * size.height * 4, 1); // Courtesy of Dirk. Thanks!
    if (bitmapData == NULL)
    {
        fprintf (stderr, "Error: Memory not allocated!");
        CGColorSpaceRelease(colorSpace);
        return NULL;
    }
	
    CGContextRef context = CGBitmapContextCreate (bitmapData, size.width, size.height, 8, size.width * 4, colorSpace, kCGImageAlphaPremultipliedFirst);
    CGColorSpaceRelease(colorSpace );
    if (context == NULL)
    {
        fprintf (stderr, "Error: Context not created!");
        free (bitmapData);
		return NULL;
    }
	
	CGRect rect = CGRectMake(0.0f, 0.0f, size.width, size.height);
	CGContextDrawImage(context, rect, image.CGImage);
	unsigned char *data = CGBitmapContextGetData(context);
	CGContextRelease(context);
	
    return data;
}

视图持久性和归档

 

//持久化
- (void) updateDefaults
{
	NSMutableArray *colors =  [[NSMutableArray alloc] init];
	NSMutableArray *locs = [[NSMutableArray alloc] init];
	
	for (DragView *dv in [[self.view viewWithTag:201] subviews]) 
	{
		[colors addObject:dv.whichFlower];
		[locs addObject:NSStringFromCGRect(dv.frame)];
	}
	
	[[NSUserDefaults standardUserDefaults] setObject:colors forKey:@"colors"];
	[[NSUserDefaults standardUserDefaults] setObject:locs forKey:@"locs"];
	[[NSUserDefaults standardUserDefaults] synchronize];

	[colors release];
	[locs release];
}
//删除
[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"colors"];
[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"locs"];
//加载
NSMutableArray *colors = [[NSUserDefaults standardUserDefaults] objectForKey:@"colors"];
NSMutableArray *locs = [[NSUserDefaults standardUserDefaults] objectForKey:@"locs"];

//归档

@interface DragView : UIImageView
{
	CGPoint startLocation;
	NSString *whichFlower;
}
@property (retain) NSString *whichFlower;
@end

@implementation DragView
@synthesize whichFlower;
//保存
- (void) encodeWithCoder: (NSCoder *)coder
{
	[coder encodeCGRect:self.frame forKey:@"viewFrame"];
	[coder encodeObject:self.whichFlower forKey:@"flowerType"];
}

//初始化
- (id) initWithCoder: (NSCoder *)coder
{
	[super initWithFrame:CGRectZero];
	self.frame = [coder decodeCGRectForKey:@"viewFrame"];
	self.whichFlower = [coder decodeObjectForKey:@"flowerType"];
	self.image = [UIImage imageNamed:self.whichFlower];
	self.userInteractionEnabled = YES;
	return self;
}

//保存
NSArray *flowers = [[self.view viewWithTag:201] subviews];
[NSKeyedArchiver archiveRootObject:flowers toFile:DATAPATH];

//加载
NSArray *flowers = [NSKeyedUnarchiver unarchiveObjectWithFile:DATAPATH];

  使用NSUndoManager来执行Undo和reDo操作

// Initialize the undo manager for this application
self.undoManager = [[NSUndoManager alloc] init];
//设置UNDO次数
[self.undoManager setLevelsOfUndo:999];
//注册 在视图时同注册
[[self.undoManager prepareWithInvocationTarget:self] setPosition:self.center];

//然后是否正在undo
while ([self.undoManager isUndoing]);
// Don't show the undo button if the undo stack is empty
//是否能undo
if (!self.undoManager.canUndo) 
	self.navigationItem.leftBarButtonItem = nil;
else
	self.navigationItem.leftBarButtonItem = BARBUTTON(@"Undo", @selector(undo));
//最后再处理undo
[self.undoManager undo];

   

 

 

 

 

 

 

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