在ios程序的编写过程中，很多时候我们都要自定义自己的UI，而不是使用cocoatouch中原有的。说起对UI的更改，很多时候我们只是修改一下原有UI的背景啊，颜色之类的，以达到新的要求。
在此之前呢，设置UINavigationController的背景颜色，我会使用如下的代码：
首先看.h文件
- #import <UIKit/UIKit.h>
- @interface UINavigationBar (CustomBar)
- - (void)customNavigationBar;
- @end
.m文件
- #import "UINavigationBar+CustomBar.h"
- #import <QuartzCore/QuartzCore.h>
- @implementation UINavigationBar (CustomBar)
- - (void)customNavigationBar
- {
- if ([self respondsToSelector:@selector(setBackgroundImage:forBarMetrics:)])
- {
- CGSize titleSize = self.bounds.size; //获取Navigation Bar的位置和大小
- UIImage *image = [UIImage imageNamed:@"img_nav_backimg"];
- UIGraphicsBeginImageContext(titleSize);
- [image drawInRect:CGRectMake(0, 0, titleSize.width, titleSize.height)];
- UIImage* scaledImage = UIGraphicsGetImageFromCurrentImageContext();
- UIGraphicsEndImageContext();
- [self setBackgroundImage:scaledImage forBarMetrics:UIBarMetricsDefault];
- }
- else
- {
- [self drawRect:self.bounds];
- }
- // [self drawRoundCornerAndShadow];
- }
- - (void)drawRect:(CGRect)rect {
- [[UIImage imageNamed:@"img_nav_backimg.png"] drawInRect:rect];
- }
- - (void)drawRoundCornerAndShadow {
- CGRect bounds = self.bounds;
- bounds.size.height +=10;
- UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:bounds
- byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerTopRight)
- cornerRadii:CGSizeMake(10.0, 10.0)];
- CAShapeLayer *maskLayer = [CAShapeLayer layer];
- maskLayer.frame = bounds;
- maskLayer.path = maskPath.CGPath;
- [self.layer addSublayer:maskLayer];
- self.layer.mask = maskLayer;
- self.layer.shadowOffset = CGSizeMake(3, 3);
- self.layer.shadowOpacity = 0.7;
- self.layer.shadowPath = [UIBezierPath bezierPathWithRect:self.bounds].CGPath;
- }
- @end
调用时如下：
- //设置导航栏底图
- + (void)setNavigationCtrollerBackImg:(UINavigationController *)naviCtl
- {
- [naviCtl.navigationBar customNavigationBar];
- }
这样的写法是一个不错的选择。如果说要修改
self.title的颜色呢，相信很多人都会想到自定义UILabel，然后self.navigationControl.titleView = Label，这针对几个页面也许是一个比较不错的选择，可是如果很多页面，甚至所有的页面都需要呢，你或许会说设置一个基础类，然
后从这个基础类继承过来，这也可以，但是不是最简便的方式。
好了，说了这么多，我们来看看我最近看到的一个比较方便的方法吧：
- <pre name="code" class="plain">#pragma mark 初始化导航栏主题
- - (void)setNavTheme
- {
- // 1.设置导航栏背景
- UINavigationBar *bar = [UINavigationBar appearance];
- [bar setBackgroundImage:[UIImage resizeImage:@"NavigationBar_Background.png"] forBarMetrics:UIBarMetricsDefault];
- // 状态栏
- [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleBlackOpaque;
- // 2.设置导航栏文字属性
- NSMutableDictionary *barAttrs = [NSMutableDictionary dictionary];
- [barAttrs setObject:[UIColor darkGrayColor] forKey:UITextAttributeTextColor];
- [barAttrs setObject:[NSValue valueWithUIOffset:UIOffsetMake(0, 0)] forKey:UITextAttributeTextShadowOffset];
- [bar setTitleTextAttributes:barAttrs];
- // 3.按钮
- UIBarButtonItem *item = [UIBarButtonItem appearance];
- [item setBackgroundImage:[UIImage resizeImage:@"BarButtonItem_Normal.png"] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
- [item setBackgroundImage:[UIImage resizeImage:@"BarButtonItem_Pressed.png"] forState:UIControlStateHighlighted barMetrics:UIBarMetricsDefault];
- NSMutableDictionary *itemAttrs = [NSMutableDictionary dictionaryWithDictionary:barAttrs];
- [itemAttrs setObject:[UIFont boldSystemFontOfSize:13] forKey:UITextAttributeFont];
- [item setTitleTextAttributes:itemAttrs forState:UIControlStateNormal];
- [item setTitleTextAttributes:itemAttrs forState:UIControlStateHighlighted];
- [item setTitleTextAttributes:itemAttrs forState:UIControlStateDisabled];
- // 4.返回按钮
- [item setBackButtonBackgroundImage:[UIImage resizeImage:@"BarButtonItem_Back_Normal.png"] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
- [item setBackButtonBackgroundImage:[UIImage resizeImage:@"BarButtonItem_Back_Pressed.png"] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
- //返回按钮的标题
- UIBarButtonItem *barButtonItem = [[UIBarButtonItem alloc] init];
- barButtonItem.title = @"buttonName";
- self.navigationItem.backBarButtonItem = barButtonItem;
- [barButtonItem release]
- }</pre><br><br>
这个方法极大的减轻了自定义带来的代码开销，用在换肤方面可能会更好的体现。是不是很不错啊！