iOS小知识点记录

1>UITextField实现leftView:

self.inputTextField = [[UITextField alloc]initWithFrame:CGRectMake(10, 10, 200, 25)];
    self.inputTextField.delegate = self;
    self.inputTextField.font = [UIFont systemFontOfSize:15];
    self.inputTextField.placeholder = @" 想说点什么?";
    // 设置textField显示图标
    UIView *placeHolderView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 20, 30)];
    UIImageView *icon = [[UIImageView alloc]initWithFrame:CGRectMake(5, 7, 15, 15)];
    icon.backgroundColor = [UIColor redColor]; // 这里我只是设置了颜色,你改成图片就行
    [placeHolderView addSubview:icon];
    self.inputTextField.leftView = placeHolderView;
    self.inputTextField.leftViewMode = UITextFieldViewModeAlways;
    self.inputTextField.backgroundColor = [UIColor whiteColor];
    [self addSubview:_inputTextField];

注意一定要设置:     self.inputTextField.leftViewMode = UITextFieldViewModeAlways;  否则不会显示的哟...

2>有时候程序运行崩溃,是因为全局断点造成的哟...

3>设置Xib画的label顶部对齐:

参考链接: http://blog.csdn.net/u013316626/article/details/71059601

- (void)drawRect:(CGRect)rect {
    
    [super drawRect:rect];
    [self.contentLabel sizeToFit];
} 

4>整体框架搭建基本设置:

效果图:

NavigationController:

+ (void)initialize {
    UINavigationBar *bar = [UINavigationBar appearance];
    [bar setBarTintColor:[UIColor whiteColor]];
    
    NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
    attrs[NSFontAttributeName] = [UIFont systemFontOfSize:16];
    attrs[NSForegroundColorAttributeName] = [UIColor blackColor];
    [bar setTitleTextAttributes:attrs];
}

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    if (self.childViewControllers.count > 0) {
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        [button setImage:[UIImage imageNamed:@"back"] forState:UIControlStateNormal];
        button.size = CGSizeMake(30, 30);
        [button addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
        viewController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
        // 隐藏tabbar
        viewController.hidesBottomBarWhenPushed = YES;
    }
    [super pushViewController:viewController animated:animated];
}

- (void)back {
    [self popViewControllerAnimated:YES];
}

TabBarController:

#pragma mark - 统一设置所有 UITabBarItem 的文字属性
+ (void)initialize {
    NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
    attrs[NSFontAttributeName] = [UIFont systemFontOfSize:12];
    attrs[NSForegroundColorAttributeName] = [UIColor grayColor];
    
    NSMutableDictionary *selectedAttrs = [NSMutableDictionary dictionary];
    selectedAttrs[NSFontAttributeName] = attrs[NSFontAttributeName];
    selectedAttrs[NSForegroundColorAttributeName] = [UIColor colorWithRed:255/255.0 green:125/255.0 blue:0 alpha:1];
    
    UITabBarItem *items = [UITabBarItem appearance];
    [items setTitleTextAttributes:attrs forState:UIControlStateNormal];
    [items setTitleTextAttributes:selectedAttrs forState:UIControlStateSelected];
}

#pragma mark - 初始化
- (instancetype)init {
    if (self = [super init]) {
        [self addChildViewControllers];
        [self addComposeButton];
    }
    return self;
}

#pragma mark - 添加所有子控制器
- (void)addChildViewControllers {
    [self addChildViewControllerClassName:@"NNHomePageController" title:@"首页" imageName:@"tabbar_home"];
    [self addChildViewControllerClassName:@"NNFoundController" title:@"发现" imageName:@"tabbar_discover"];
    [self addChildViewController: [[UIViewController alloc] init]];
    [self addChildViewControllerClassName:@"NNMessageController" title:@"消息" imageName:@"tabbar_message_center"];
    [self addChildViewControllerClassName:@"NNMyController" title:@"我的" imageName:@"tabbar_profile"];
}

#pragma mark - 设置所有子控制器
- (void)addChildViewControllerClassName:(NSString *)className title:(NSString *)title imageName:(NSString *)imageName
{
    UIViewController *viewController = [[NSClassFromString(className) alloc] init];
    NNNavigationController *nav = [[NNNavigationController alloc] initWithRootViewController:viewController];
    viewController.title = title;
    viewController.view.backgroundColor = [UIColor whiteColor];
    viewController.tabBarItem.image = [UIImage imageNamed: imageName];
    viewController.tabBarItem.selectedImage = [UIImage imageNamed:[NSString stringWithFormat:@"%@_highlighted", imageName]];
    [self addChildViewController:nav];
}

#pragma mark - 添加中间的按钮
- (void)addComposeButton {
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    [button setImage:[UIImage imageNamed:@"tabBar_publish_icon"] forState:UIControlStateNormal];
    [button setImage:[UIImage imageNamed:@"tabBar_publish_icon_highlighted"] forState:UIControlStateSelected];
    [button addTarget:self action:@selector(composeButtonClick:) forControlEvents:UIControlEventTouchUpInside];
    self.composeButton = button;
    [self.tabBar addSubview:button];
    [self.tabBar bringSubviewToFront:button];
    CGFloat width = self.tabBar.bounds.size.width / self.childViewControllers.count - 2;
    self.tabBar.tintColor = [UIColor colorWithRed:68/255.0 green:173/255.0 blue:159/255.0 alpha:1];
    button.frame = CGRectInset(self.tabBar.bounds, 2 * width, 0);
}

#pragma mark - 点击写文章按钮
- (void)composeButtonClick:(UIButton *)button {
    NSLog(@"
点击了写文章按钮");
    AddViewController *addVc = [AddViewController new];
    NNNavigationController *nav = [[NNNavigationController alloc]initWithRootViewController:addVc];
    [self presentViewController: nav animated:YES completion:nil];
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [self.tabBar bringSubviewToFront:self.composeButton];
}