在导航条的下方加上阴影 navgationbar-优快云博客

本文介绍了一个用于iOS开发的自定义UINavigationBar阴影效果的类别。通过扩展UINavigationBar，开发者可以轻松地为导航栏添加阴影效果，包括设置阴影的颜色、透明度、偏移和半径等属性。

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工程需要包含 QuartzCore.Framework。

 
        // 
       
        // UINavigationBar+JTDropShadow.h 
       
        // 
       
        // Created by james on 9/20/11. 
       
        //  http://ioscodesnippet.tumblr.com 
       
        // 
       
        #import  
       
        @interface 
         UINavigationBar 
         (JTDropShadow) 
       
        - (
        void
        )dropShadowWithOffset:(CGSize)offset 
       
        radius
        :(CGFloat)radius 
       
        color
        :(
        UIColor 
         *)color 
       
        opacity
        :(CGFloat)opacity; 
       
        @end 
       
        // 
       
        // UINavigationBar+JTDropShadow.m 
       
        // 
       
        // Created by james on 9/20/11. 
       
        //  http://ioscodesnippet.tumblr.com 
       
        // 
       
        #import "UINavigationBar+JTDropShadow.h" 
       
        #import  
       
        @implementation 
         UINavigationBar 
         (JTDropShadow) 
       
        - (
        void
        )dropShadowWithOffset:(CGSize)offset 
       
        radius
        :(CGFloat)radius 
       
        color
        :(
        UIColor 
         *)color  
       
        opacity
        :(CGFloat)opacity { 
       
        // Creating shadow path for better performance 
       
        CGMutablePathRef 
         path = CGPathCreateMutable(); 
       
        CGPathAddRect(path, 
        NULL
        , 
        self
        .bounds
        ); 
       
        self
        .layer
        .shadowPath 
         = path; 
       
        CGPathCloseSubpath(path); 
       
        CGPathRelease(path); 
       
        self
        .layer
        .shadowColor 
         = color
        .CGColor
        ; 
       
        self
        .layer
        .shadowOffset 
         = offset; 
       
        self
        .layer
        .shadowRadius 
         = radius; 
       
        self
        .layer
        .shadowOpacity 
         = opacity; 
       
        // Default clipsToBounds is YES, will clip off the shadow, so we disable it. 
       
        self
        .clipsToBounds 
         = 
        NO
        ; 
       
        } 
       
        @end 
       
        //用法如下 
       
        - (
        void
        )viewDidLoad { 
       
        [
        super 
         viewDidLoad
        ]; 
       
        ... 
       
        [
        self
        .navigationController
        .navigationBar 
         dropShadowWithOffset
        :CGSizeMake(
        0
        , 
        3
        ) 
       
        radius
        :
        1 
       
        color
        :[
        UIColor 
         darkGrayColor
        ] 
       
        opacity
        :
        1
        ]; 
       
        ... 
       
        }