最近我突然發現UINavigationbar背景修改的方法不起作用了，代碼如下：
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@implementation
-(void)drawRect:(CGRect)rect { } @end |
發現原來是iOS 5的原因，如果運行在iOS 5以下的版本就沒有問題了。經過實驗以下方法適合iOS 5（放在ViewDidLoad中）：
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第一條if語句的作用是防止程序在iOS 5以下的版本中崩潰。
這樣，依靠這兩段代碼，我的UINavigationbar的背景問題在iOS 5及以下版本中得到了完美的解決。
iOS5之前是如何自定義UINavigationBar背景的？
在iOS5.0中我們可以非常簡單的設置UINavigationBar的背景（setBackgroundImage:
forBarMetrics:方法），而這對於之前的版本是不可同日而語的。通過網絡收集整理了一下以前的各種方式，只能作爲學習筆記做個記錄，菜鳥學習而已。高人就跳過吧。
方法一：主要技巧就是用視圖的drawInRect:方法繪製
如下爲創建了一個UINavigationBar Category
// 其實現代碼如下
@implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
//顏色填充
UIColor *color = [UIColor redColor];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetFillColor(context,CGColorGetComponents([color CGColor]));
CGContextFillRect(context,rect);
self.tintColor = color;
//圖片填充
UIColor *color = [UIColor colorWithRed:46.0f/255.0f green:87.0f/255.0f blue:29.0f/255.0f alpha:1.0f];
UIImage *img = [UIImage imageNamed:@"bg.png"];
[img drawInRect:CGRectMake(0,0,self.frame.size.width,self.frame.size.height)];
self.tintColor = color;
}
@end
自定義圖片背景以下兩句代碼是關鍵：
UIImage *img = [UIImage imageNamed:@"bg.png"];
[img drawInRect:CGRectMake(0,0,self.frame.size.width,self.frame.size.height)];
或者：
UIImage *img = [UIImage imageNamed:@"bg.png"];
CGPoint point = {0,0};
[img
drawAtPoint:point];
或者：
//加入旋轉座標系代碼
// Drawing code
UIImage
CGContextRef
CGContextTranslateCTM(context,
CGContextScaleCTM(context,
CGPoint
CGImageRef
CGContextDrawImage(context,
CGContextDrawImage(context,
CGContextDrawImage(context,
擴展UINavigationBar的drawRect方法的這種自定義方法會影響到工程項目中所有的導航條欄。
類似在iOS5.0中，由於UINavigationBar、UIToolBar和UITabBar的實現方式改變，而drawRect:方法不會被調用了，所以就不支持這種通過定義導航條類別的方式來自定義導航條了。除非在這類控件的子類中實現。
//子類可以調用drawRect:方法
@interface MyNavigationBar : UINavigationBar
@end
@implementation MyNavigationBar
- (void)drawRect:(CGRect)rect {
[super drawRect:rect];
}
@end
方法二：定義UINavigationBar的一個static函數
1 + (UINavigationBar *)createNavigationBarWithBackgroundImage:(UIImage *)backgroundImage title:(NSString *)title {
2 UINavigationBar *customNavigationBar = [[[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)] autorelease];
3 UIImageView *navigationBarBackgroundImageView = [[UIImageView alloc] initWithImage:backgroundImage];
4 [customNavigationBar addSubview:navigationBarBackgroundImageView];
5 UINavigationItem *navigationTitle = [[UINavigationItem alloc] initWithTitle:title];
6 [customNavigationBar pushNavigationItem:navigationTitle animated:NO];
7 [navigationTitle release];
8 [navigationBarBackgroundImageView release];
9 return customNavigationBar;
10 }
下面是在需要生成UINavgationBar
的地方添加的代碼
View
Code
1 self.navigationController.navigationBar.hidden = YES;
2 UIImage *navigationBarBackgroundImage =[UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"topbar-bg" ofType:@"png"]];
3 UINavigationBar *customNavigationBar = [YOUR_Util_Class createNavigationBarWithBackgroundImage:navigationBarBackgroundI mage title:nil];
4 [self.view addSubview:customNavigationBar];
5
6 UIButton *backButton = [[UIButton alloc] initWithFrame:CGRectMake(0.0, 0.0, 75.0, 30.0)];
7 if (_backButtonImage) {
8 [backButton setImage:_backButtonImage forState:UIControlStateNormal];
9 }else {
10 [backButton setImage:[UIImage imageNamed:@"btnback.png"] forState:UIControlStateNormal];
11 }
12
13 [backButton addTarget:self action:@selector(backButtonCliked:) forControlEvents:UIControlEventTouchUpInside];
14 UIBarButtonItem *backBarButton = [[UIBarButtonItem alloc] initWithCustomView:backButton];
15 customNavigationBar.topItem.leftBarButtonItem = backBarButton;
16
17 [backButton release];
18 [backBarButton release];
19
20 UIButton *addButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 43, 30)];
21 UIBarButtonItem *addBarButton = [[UIBarButtonItem alloc] initWithCustomView:addButton];
22 if (_isFromFavorites) {
23 [addButton setImage:[UIImage imageNamed:@"btn-delete-0.png"] forState:UIControlStateNormal];
24 [addButton addTarget:self action:@selector(deleteButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
25 }else {
26 [addButton setImage:[UIImage imageNamed:@"btn_add.png"] forState:UIControlStateNormal];
27 [addButton addTarget:self action:@selector(addButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
28 }
29 customNavigationBar.topItem.rightBarButtonItem = addBarButton;
30 [addButton release];
31 [addBarButton release];
此代碼效果圖如下：
這一方法轉載自：http://www.cnblogs.com/moshengren/archive/2010/10/18/1855191.html
方法三：也是自定義導航條類別，但是重寫setBackgroundImage:方法
CustomNavController.h
1 // Created by suruiqiang on 8/3/10.
2 // Copyright 2010 __MyCompanyName__. All rights reserved.
3 //
4 #pragma once
5 #import <UIKit/UIKit.h>
6 @interface UINavigationBar (UINavigationBarCategory)
7 UIImageView *bg;
8 -(UINavigationBar*)setBackgroundImage:(UIImage*)image;
9 - (void)insertSubview:(UIView *)view atIndex:(NSInteger)index;
10 @end
CustomNavController.m
1 #import "CustomerNavBarController.h "
2
3 @implementation UINavigationBar (UINavigationBarCategory)
4 -(UINavigationBar*)setBackgroundImage:(UIImage*)image
5 {
6 UINavigationBar *NavBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
7 if(image == nil) return NavBar;
8 bg = [[UIImageView alloc]initWithImage:image];
9 bg.frame = CGRectMake(0.f, 0.f, self.frame.size.width, self.frame.size.height);
10 [NavBar addSubview:bg];
11 [NavBar sendSubviewToBack:bg];
12 [bg release];
13 return NavBar;
14 }
15
16 - (void)insertSubview:(UIView *)view atIndex:(NSInteger)index
17 {
18 [super insertSubview:view atIndex:index];
19 [self sendSubviewToBack:bg];
20 }
21 @end
調用代碼示例：
- (void)viewDidLoad {
[super viewDidLoad];
[[self.navigationController navigationBar] setBackgroundImage:[UIImage imageNamed:@"NavigationBarBackground.png"]];
//在下面添加你自己的功能代碼
***********
}
此方法轉載自：http://www.cnblogs.com/moshengren/archive/2010/10/18/1855202.html
方法四：通過導入QuartzCore框架繪製CALayer層來自定義
#import <QuartzCore/QuartzCore.h>
@interface DDNavigationViewController : UINavigationController<UINavigationControllerDe legate> {
CALayer *_barBackLayer;
}
@end
View
Code
1 @implementation DDNavigationViewController
2
3 - (id)initWithRootViewController:(UIViewController *)rootViewController {
4
5 self = [super initWithRootViewController:rootViewController];
6
7 self.delegate = self;
8
9 return self;
10
11 }
12
13 - (void)loadView {
14
15 [super loadView];
16
17 UINavigationBar *bar = self.navigationBar;
18
19 CALayer*layer = [CALayer layer];
20
21 UIImage *navBarImage = [UIImage imageNamed:@"navigationBarBackground.png"];
22
23 layer.contents = (id)navBarImage.CGImage;
24
25 layer.frame= CGRectMake(0, 0, 320, navBarImage.size.height);
26
27 [bar.layer insertSublayer:layer atIndex:0];
28
29 _barBackLayer = layer;
30
31 }
32
33
34 #pragma mark -
35
36 #pragma mark UINavigationControllerDelegate
37
38 - (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
39
40 [_barBackLayer removeFromSuperlayer];
41
42 [navigationController.navigationBar.layer insertSublayer:_barBackLayeratIndex:0];
43
44 }
45
46 @end
// 設置左邊的按鈕
UIBarButtonItem *returnButton = [[UIBarButtonItem alloc]initWithTitle:@”返回“style:UIBarButtonItemStyleBordered target:self action:@selector(returnMain)];
self.navigationItem.leftBarButtonItem = returnButton;
[returnButton release];
//定義右邊按鈕
UIBarButtonItem *diquButtons = [[UIBarButtonItem alloc]initWithTitle:@”編輯“style:UIBarButtonItemStyleBordered target:self action:@selector(selectArea)];
self.navigationItem.rightBarButtonItem = diquButtons;
self.diquButton = diquButtons;
[diquButtons release];
[temp release];
但是如果該方法不是很好用的話 只有用這個方法了
- (void)initNavBarItems:(NSString *)titlename{
// 設置navbar的titleview
UIView *dd = [[UIView alloc]initWithFrame:CGRectMake(-5, 0, 325, 44)];
UIImageView *imgs = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"new-nav-bg.png"]];
imgs.frame = CGRectMake(-5, 0, 325, 44);
[dd addSubview:imgs];
// 設置標題
UILabel *title = [[UILabel alloc]initWithFrame:CGRectMake(-5, 3, 320, 40)];
title.text = titlename;
title.textAlignment = UITextAlignmentCenter;
title.backgroundColor = [UIColor clearColor];
title.textColor = [UIColor whiteColor];
title.font = [UIFont boldSystemFontOfSize:22];
[dd addSubview:title];
// 設置左邊的按鈕
UIButton *left = [UIButton buttonWithType:UIButtonTypeRoundedRect];
left.frame = CGRectMake(15, 5, 60, 30);
[dd addSubview:left];