自定義TabBar

要自定義UITabBarController，首先咱們必須瞭解UITabBarController結構與其各個相關類的關係（TabBarController、TabBar、TabButton及ViewController）。其中，TabButton是一個雙態的Button（選中和未選中），行爲和CheckBox、RadioButton相似。TabBar是TabButton的容器，負責TabButton的排布和互斥，保證同時只有一個Button爲選中態。TabBarController包含了TabBar，並管理這一個ViewController的棧，在TabBar上的按鈕點擊時對棧上的ViewController位置進行相應的調整，從而保持TabBar和ViewController棧之間的一致性。      熟悉了基本結構後，通常有如下常見的方案來完整自定義TabBarController。 方案一：替換部分現有的實現      目標是替換掉系統的部分控件，可經過隱藏TabBar的方式來實現。只要作到隱藏原有的TabBar後，不要忘了在新定製的TabBar的當前選中按鈕變化時經過UITabBarController的setSelectedIndex接口設置ViewController棧的當前ViewController便可。 View Code 複製代碼 1 #import<UIKit/UIKit.h>2 @interface CustomTabBar : UITabBarController { 3 NSMutableArray *buttons; 4 int currentSelectedIndex; 5 UIImageView *slideBg; 6 } 7 8 @property (nonatomic,assign) int currentSelectedIndex; 9 @property (nonatomic,retain) NSMutableArray *buttons; 10 11 - (void)hideRealTabBar; 12 - (void)customTabBar; 13 - (void)selectedTab:(UIButton *)button; 14 15 @end 複製代碼 View Code 複製代碼 1 #import "CustomTabBar.h" 2 3 @implementation CustomTabBar 4 5 @synthesize currentSelectedIndex; 6 @synthesize buttons; 7 8 - (void)viewDidAppear:(BOOL)animated{ 9 slideBg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"bottomfocus.png"]]; 10 [self hideRealTabBar]; 11 [self customTabBar]; 12 } 13 14 - (void)hideRealTabBar{ 15 for(UIView *view in self.view.subviews){ 16 if([view isKindOfClass:[UITabBar class]]){ 17 view.hidden = YES; 18 break; 19 } 20 } 21 } 22 23 - (void)customTabBar{ 24 UIImageView *imgView = [[UIImageView alloc] initWithImage: [UIImage imageNamed:@"tabbg2.png"]]; 25 imgView.frame = CGRectMake(0, 425, imgView.image.size.width, imgView.image.size.height); 26 [self.view addSubview:imgView]; 27 slideBg.frame = CGRectMake(-30, self.tabBar.frame.origin.y, slideBg.image.size.width, slideBg.image.size.height); 28 29 //建立按鈕 30 int viewCount = self.viewControllers.count > 5 ? 5 : self.viewControllers.count; 31 self.buttons = [NSMutableArray arrayWithCapacity:viewCount]; 32 double _width = 320 / viewCount; 33 double _height = self.tabBar.frame.size.height; 34 for (int i = 0; i < viewCount; i++) { 35 UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom]; 36 btn.frame = CGRectMake(i*_width,self.tabBar.frame.origin.y, _width, _height); 37 [btn addTarget:self action:@selector(selectedTab:) forControlEvents:UIControlEventTouchUpInside]; 38 btn.tag = i; 39 [self.buttons addObject:btn]; 40 [self.view addSubview:btn]; 41 [btn release]; 42 } 43 [self.view addSubview:slideBg]; 44 UIImageView *imgFront = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"tabitem.png"]]; 45 imgFront.frame = imgView.frame; 46 [self.view addSubview:imgFront]; 47 [imgFront release]; 48 [imgView release]; 49 [self selectedTab:[self.buttons objectAtIndex:0]]; 50 51 } 52 53 - (void)selectedTab:(UIButton *)button{ 54 if (self.currentSelectedIndex == button.tag) { 55 56 } 57 self.currentSelectedIndex = button.tag; 58 self.selectedIndex = self.currentSelectedIndex; 59 [self performSelector:@selector(slideTabBg:) withObject:button]; 60 } 61 62 - (void)slideTabBg:(UIButton *)btn{ 63 [UIView beginAnimations:nil context:nil]; 64 [UIView setAnimationDuration:0.20]; 65 [UIView setAnimationDelegate:self]; 66 slideBg.frame = CGRectMake(btn.frame.origin.x - 30, btn.frame.origin.y, slideBg.image.size.width, slideBg.image.size.height); 67 [UIView commitAnimations]; 68 } 69 70 - (void) dealloc{ 71 [slideBg release]; 72 [buttons release]; 73 [super dealloc]; 74 } 75 @end 複製代碼 使用這個自定義類來建立UITabBarController View Code 複製代碼 1 // Override point for customization after application launch. 2 FirstViewController *mainViewController = [[FirstViewController alloc] init]; 3 SecondViewController *searchViewController = [[SecondViewController alloc]init]; 4 ThirdViewController *myselfViewController = [[ThirdViewController alloc]init]; 5 ForthViewController *settingViewController = [[ForthViewController alloc]init]; 6 7 //隱藏tabbar所留下的黑邊（試着註釋後你會知道這個的做用） 8 mainViewController.hidesBottomBarWhenPushed = true; 9 searchViewController.hidesBottomBarWhenPushed = true; 10 myselfViewController.hidesBottomBarWhenPushed = true; 11 settingViewController.hidesBottomBarWhenPushed = true; 12 13 mainViewController.title = @"首頁"; 14 searchViewController.title = @"搜索"; 15 myselfViewController.title = @"我"; 16 settingViewController.title = @"設置"; 17 18 //建立導航 19 UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:mainViewController ]; 20 UINavigationController *nav1 = [[ UINavigationController alloc] initWithRootViewController:searchViewController]; 21 UINavigationController *nav2 = [[UINavigationController alloc] initWithRootViewController:myselfViewController]; 22 UINavigationController *nav3 = [[UINavigationController alloc]initWithRootViewController:settingViewController]; 23 //建立數組 24 NSMutableArray *controllers = [[NSMutableArray alloc]init]; 25 [controllers addObject:nav]; 26 [controllers addObject:nav1]; 27 [controllers addObject:nav2]; 28 [controllers addObject:nav3]; 29 30 //建立tabbar 31 tabBarController = [[ CustomTabBar alloc] init]; 32 tabBarController.viewControllers = controllers; 33 tabBarController.selectedIndex = 0; 34 35 //顯示 36 [self.window addSubview:tabBarController.view]; 37 [self.window makeKeyAndVisible];