自定义按钮UIControl

写在前面

#图标和文字在一起是开发难免的问题，系统的按钮默认是图片居左的文字居右的，
且图片和文字的距离不好调整，图片的位置更是让人头疼，
故在闲暇之余封装了一个控件。
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所用到知识的

# 1、苹果系统自带的自动布局，减少第三方的依赖
# 2、kvo监听UIControl的状态
# 3、富文本的使用，如何更新约束，如何获取一段文字的宽高复制代码

先看看效果

拥有功能

1、任意调整图片和文字的间距。
2、图片的位置可以放置在上下左右不同位置。
3、支持富文本，自定义布局，高亮和选中状态。
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如何使用

/**自定义按钮初始化方法@param image 默认的图片@param title 标题@param titleFond 标题大小@param imageMargin 标题与图标的距离@param imageAlignmentTYpe 图片的显示类型@return 自定义按钮的实例*/
- (instancetype)initWithImage:(UIImage  *) imagetitle:(NSString *) titletitleFond:(UIFont *)   titleFondimageMargin:(CGFloat)    imageMarginimageAlignmentTYpe:(MyButtonImageAlignmentTYpe )imageAlignmentTYpe;_myButton = [[MyButton alloc]initWithImage:[UIImage imageNamed:@"cache_pause"]title:@"来点我啊"titleFond:[UIFont systemFontOfSize:14]imageMargin:10imageAlignmentTYpe:MyButtonImageAlignmentLeft];[self.view addSubview:_myButton];self.myButton.frame = CGRectMake(20, 100, 120, 40);self.myButton.backgroundColor = UIColor.grayColor;[self.myButton setImage:[UIImage imageNamed:@"cache_delete"] withState:UIControlStateSelected];[self.myButton setImage:[UIImage imageNamed:@"cache_pause"] withState:UIControlStateHighlighted];[self.myButton setTitle:@"选中了" withState:UIControlStateSelected];[self.myButton setTitle:@"正在按下..." withState:UIControlStateHighlighted];[self.myButton setTitleColor:UIColor.blueColor withState:UIControlStateSelected];[self.myButton setTitleColor:UIColor.yellowColor withState:UIControlStateHighlighted];这样就可以了，和普通的按钮用法一样。复制代码

关键代码

1、自定义布局（只列出了一种）
//图片居左
- (void)setImageLeftLayoutConstraint {CGFloat imageWidth  = self.normalImage.size.width;CGFloat titleWidth = [self sizeWithText:self.titleLabel.text font:self.titleLabel.font].width;CGFloat imageCenterXMargin = (imageWidth /2.0 - (imageWidth + titleWidth + self.imageMargin) / 2.0);//创建Image约束NSLayoutConstraint *imageCenterYLc = [NSLayoutConstraint constraintWithItem:self.imageView attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0];NSLayoutConstraint *imageCenterXLc = [NSLayoutConstraint constraintWithItem:self.imageView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:imageCenterXMargin];[self addConstraints:@[imageCenterYLc,imageCenterXLc]];//创建title约束NSLayoutConstraint *titleCenterYLc = [NSLayoutConstraint constraintWithItem:self.titleLabel attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0];NSLayoutConstraint *titleLeftLc = [NSLayoutConstraint constraintWithItem:self.titleLabel attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.imageView attribute:NSLayoutAttributeRight multiplier:1.0 constant:self.imageMargin];[self addConstraints:@[titleCenterYLc,titleLeftLc]];
}//获取文字的宽高
- (CGSize)sizeWithText:(NSString *)text font:(UIFont *)font {NSDictionary *attrs = @{NSFontAttributeName : font};return [text boundingRectWithSize:CGSizeMake(MAXFLOAT, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;
}//kvo监听
- (void)addObserver {[self addObserver:selfforKeyPath:@"enabled"options: NSKeyValueObservingOptionNewcontext:nil];[self addObserver:selfforKeyPath:@"selected"options: NSKeyValueObservingOptionNewcontext:nil];[self addObserver:selfforKeyPath:@"highlighted"options: NSKeyValueObservingOptionNewcontext:nil];[self.titleLabel addObserver:selfforKeyPath:@"text"options:NSKeyValueObservingOptionNewcontext:nil];
}//kvo 监听处理（只列出了部分）
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context {if ([keyPath isEqualToString:@"selected"]) {if(self.selected) {self.imageView.image           = self.selectedImage ? self.selectedImage : self.normalImage;self.backgroundColor           = self.selectedBackgroundColor  ? self.selectedBackgroundColor : self.normalBackgroundColor;if (!self.selectedTitleAttribute && !self.normalTitleAttribute) {self.titleLabel.text       = self.selectedTitle ? self.selectedTitle : self.normalTitle;self.titleLabel.textColor  = self.selectedTitleColor ? self.selectedTitleColor : self.normalTitleColor;return;}self.titleLabel.attributedText = self.selectedTitleAttribute ? self.selectedTitleAttribute : self.normalTitleAttribute;} else {self.imageView.image           = self.normalImage;self.backgroundColor           = self.normalBackgroundColor;if (!self.normalTitleAttribute) {self.titleLabel.text       = self.normalTitle;self.titleLabel.textColor  = self.normalTitleColor;return;}self.titleLabel.attributedText = self.normalTitleAttribute;}} //监听到字体变化，更新自动布局if ([keyPath isEqualToString:@"text"]) {[self removeConstraints:self.constraints];[self.superview layoutIfNeeded];[self updateConstraints:self.imageAlignmentTYpe];[self.superview layoutIfNeeded];}
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以上只是部分代码，详细代码请查看

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自定义按钮 https://github.com/dudongge/MyApp

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