在某些场景我们想让Label像UIButton这种控件一样，可以设置内容边距，来使整体布局可拓展性增强。刚好项目中遇到需要使用的场景，就通过category为UILabel添加内边距属性。
Demo下载：https://github.com/icofans/UIlabel-Insets
.h
@interface UILabel (Insets)
/**
和UIbutton相似，内边距属性
控制字体与控件边界的间隙
*/
@property (nonatomic, assign) UIEdgeInsets contentInsets;
@end
.m
@implementation UILabel (Insets)
static char kContentInsetsKey;
static char kshowContentInsetsKey;
- (void)setContentInsets:(UIEdgeInsets)contentInsets
{
objc_setAssociatedObject(self, &kContentInsetsKey, NSStringFromUIEdgeInsets(contentInsets), OBJC_ASSOCIATION_COPY_NONATOMIC);
objc_setAssociatedObject(self, &kshowContentInsetsKey, @YES, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
- (UIEdgeInsets)contentInsets
{
return UIEdgeInsetsFromString(objc_getAssociatedObject(self, &kContentInsetsKey));
}
+ (void)load
{
[super load];
// class_getInstanceMethod()
Method fromMethod = class_getInstanceMethod([self class], @selector(drawTextInRect:));
Method toMethod = class_getInstanceMethod([self class], @selector(tt_drawTextInRect:));
// class_addMethod()
if (!class_addMethod([self class], @selector(drawTextInRect:), method_getImplementation(toMethod), method_getTypeEncoding(toMethod))) {
method_exchangeImplementations(fromMethod, toMethod);
}
}
- (void)tt_drawTextInRect:(CGRect)rect
{
BOOL show = objc_getAssociatedObject(self, &kshowContentInsetsKey);
if (show) {
rect = UIEdgeInsetsInsetRect(rect, self.contentInsets);
}
[self tt_drawTextInRect:rect];
}
@end
使用很简单
textLabel.contentInsets = UIEdgeInsetsMake(0, 16, 0, 0);
