自定义下拉框的封装

／＊＊＊＊＊＊＊＊.h文件＊＊＊＊＊＊＊＊＊＊／

@interface HWDropdownMenu : UIView

+ (instancetype)menu;

/**

* 显示

*/

- (void)showFrom:(UIView *)from;

/**

* 销毁

*/

- (void)dismiss;

/**

* 内容

*/

@property (nonatomic, strong) UIView *content;

/**

* 内容控制器

*/

@property (nonatomic, strong) UIViewController *contentController;

@end

／＊＊＊＊＊＊＊＊＊ .m文件＊＊＊＊＊＊＊＊＊＊／

@interface HWDropdownMenu()

/**

* 将来用来显示具体内容的容器

*/

@property (nonatomic, weak) UIImageView *containerView;

@end

@implementation HWDropdownMenu

- (UIImageView *)containerView

{

if (!_containerView) {

// 添加一个灰色图片控件

UIImageView *containerView = [[UIImageView alloc] init];

containerView.image = [UIImage imageNamed:@"popover_background"];

containerView.userInteractionEnabled = YES; // 开启交互

[self addSubview:containerView];

self.containerView = containerView;

}

return _containerView;

}

- (id)initWithFrame:(CGRect)frame

{

self = [super initWithFrame:frame];

if (self) {

// 清除颜色

self.backgroundColor = [UIColor clearColor];

}

return self;

}

+ (instancetype)menu

{

return [[self alloc] init];

}

- (void)setContent:(UIView *)content

{

_content = content;

// 调整内容的位置

content.x = 10;

content.y = 15;

// 调整内容的宽度

// content.width = self.containerView.width - 2 * content.x;

// 设置灰色的高度

self.containerView.height = CGRectGetMaxY(content.frame) + 11;

// 设置灰色的宽度

self.containerView.width = CGRectGetMaxX(content.frame) + 10;

// 添加内容到灰色图片中

[self.containerView addSubview:content];

}

- (void)setContentController:(UIViewController *)contentController

{

_contentController = contentController;

self.content = contentController.view;

}

/**

* 显示

*/

- (void)showFrom:(UIView *)from

{

// 1.获得最上面的窗口

UIWindow *window = [[UIApplication sharedApplication].windows lastObject];

// 2.添加自己到窗口上

[window addSubview:self];

// 3.设置尺寸

self.frame = window.bounds;

// 4.调整灰色图片的位置

// 默认情况下，frame是以父控件左上角为坐标原点

// 转换坐标系

CGRect newFrame = [from convertRect:from.bounds toView:window];

// CGRect newFrame = [from.superview convertRect:from.frame toView:window];

self.containerView.centerX = CGRectGetMidX(newFrame);

self.containerView.y = CGRectGetMaxY(newFrame);

}

/**

* 销毁

*/

- (void)dismiss

{

[self removeFromSuperview];

}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

[self dismiss];

}

@end