我有一个带有标签属性和背景图像的以编程方式生成的 UIButton。轻按时，背景图像变为灰色，但文本不会。如何使标签也指示它何时被点击？
根据要求，我的按钮代码：
#import "BCB.h"
@implementation BCB
@synthesize cardText;
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
[self setFrame:frame];
cardText = cardText = [[MyLabel alloc]
initWithFrame:(CGRect){8, 8, 144, 186}];
cardText.numberOfLines = 0;
cardText.font = [UIFont fontWithName:@"Helvetica" size:18.0];
cardText.textColor = [UIColor whiteColor];
cardText.backgroundColor = [UIColor clearColor];
cardText.lineBreakMode = NSLineBreakByWordWrapping;
[self addSubview:cardText];
[self setBackgroundImage:[UIImage imageNamed:@"BC" ] forState:UIControlStateNormal];
}
return self;
}
@end
和 MyLabel 代码：
#import "MyLabel.h"
@implementation MyLabel
// Helper function to actually set the text.
- (void)reallySetText:(NSString*)text
{
[super setText:text];
}
// Function to top align text within a label.
- (void)topAlign
{
// Get the size of the text box containing the label with its current font and size.
CGSize textSize = [self.text sizeWithFont:self.font
constrainedToSize:(CGSize){self.frame.size.width, self.frame.size.height}
lineBreakMode:NSLineBreakByWordWrapping];
// Trim the frame up to exactly fit the text.
self.frame = (CGRect){self.frame.origin.x, self.frame.origin.y, textSize.width, textSize.height};
}
// Shrink font until it fits the provided frame.
CGFloat maxSizeThatFitsFrame(MyLabel* labelCopy, CGFloat fontSize, CGRect rect)
{
while (labelCopy.frame.size.height > rect.size.height && fontSize > 4.0f)
{
fontSize -= 0.5f;
labelCopy.font = [UIFont fontWithName:@"Helvetica" size:fontSize];
[labelCopy topAlign];
}
return fontSize;
}
// Overloading the drawTextInRect method to topAlign the text as well.
-(void)drawTextInRect:(CGRect)rect
{
[super drawTextInRect:rect];
[self topAlign];
}
// Function to set the label to have the provided text within the provided rectangle with the provided initial font size.
- (void)setText:(NSString *)text inFrame:(CGRect)rect withFontSize:(CGFloat)fontSize andColor:(UIColor*)color
{
// Set the text.
[super setText:text];
// Set the frame.
[self setFrame:rect];
// Make a copy of the label.
MyLabel* labelCopy = [[MyLabel alloc]
initWithFrame:
(CGRect){
self.frame.origin.x,
self.frame.origin.y,
self.frame.size.width,
self.frame.size.height+240}];
// Make the text wrap properly.
labelCopy.numberOfLines = 0;
labelCopy.lineBreakMode = NSLineBreakByWordWrapping;
// Set the copy's text.
[labelCopy reallySetText:self.text];
// Set the copy's font.
labelCopy.font = [UIFont fontWithName:@"Helvetica" size:fontSize];
// Top align the copy.
[labelCopy topAlign];
// If the copy's height is larger than the rectangle's height, resize it until it fits.
if (labelCopy.frame.size.height > rect.size.height)
{
fontSize = maxSizeThatFitsFrame(labelCopy, fontSize, rect);
}
// Set the label's font to a size that fits.
[self setFont:[UIFont fontWithName:@"Helvetica" size:fontSize]];
// Set the label's color.
self.textColor = color;
// Make the text wrap properly.
self.numberOfLines = 0;
self.lineBreakMode = NSLineBreakByWordWrapping;
// Top align the label.
[self topAlign];
}
@end