在iOS开发的过程中,我们经常需要修改NavigationController的背景颜色,当使用方法[self.navigationController.navigationBar setBackgroundColor:[UIColor redColor]]时,运行的结果并不能修改北京颜色:
现在提供一种新方法来解决这个问题:
写一个NavigationBar写一个类别:
@interface UINavigationBar (BackgroundColor)
//设置navigationBar的背景颜色
- (void)lt_setBackgroundColor:(UIColor *)backgroundColor;
@end
@implementation UINavigationBar (BackgroundColor)
static char overlayKey;
- (UIView *)overlay
{
return objc_getAssociatedObject(self, &overlayKey);
}
- (void)setOverlay:(UIView *)overlay
{
objc_setAssociatedObject(self, &overlayKey, overlay, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}
- (void)lt_setBackgroundColor:(UIColor *)backgroundColor
{
if (!self.overlay) {
[self setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
[self setShadowImage:[UIImage new]]; // insert an overlay into the view hierarchy
self.overlay = [[UIView alloc] initWithFrame:CGRectMake(0, -20, [UIScreen mainScreen].bounds.size.width, 64)];
[self insertSubview:self.overlay atIndex:0];
}
self.overlay.backgroundColor = backgroundColor;
}
@end
注意:在使用objc_getAssociatedObject需要引入头文件 #import <objc/runtime.h>