self.textField.clearButtonMode = UITextFieldViewModeWhileEditing;

说明：

UITextField.clearButtonMode：清空输入的字符，有以下几种模式

UITextFieldViewModeAlways，不为空，获得焦点与没有获得焦点都显示清空按钮

UITextFieldViewModeNever,不显示清空按钮

UITextFieldViewModeWhileEditing,不为空，且在编辑状态时（及获得焦点）显示清空按钮

UITextFieldViewModeUnlessEditing, 不为空，且不在编译状态时（焦点不在输入框上）显示清空按钮

扩展：关于键盘类型(UITextField.keyboardType),UITextField.enablesReturnKeyAutomatically = YES当UITextField不为空时高亮,［UITextField ResignFirstResponder］关闭键盘

通过一个视图，定义其位置跟背景就可以，下面代码仅供参考

         self.backgroundView = nil;

         self.backgroundColor = [UIColor clearColor];

         UIView* _lineView = [[UIView alloc] initWithFrame:CGRectMake(kInput_OnlyText_Cell_LeftPading, 43.5, kScreen_Width-*kInput_OnlyText_Cell_LeftPading, 0.5)];

        _lineView.backgroundColor = [UIColor colorWithHexString:@"0xaebdc9"];

        [self.contentView addSubview:_lineView];

   self.myTableView.separatorStyle = UITableViewCellSeparatorStyleNone;//不加换行线

    self.myTableView.backgroundColor = [UIColor colorWithHexString:@"0xfafafa"];

    UIView *upBgView = [[UIView alloc] initWithFrame:self.view.bounds];

    upBgView.backgroundColor =[UIColor colorWithHexString:@"0x29333f"];

    [upBgView setY:-CGRectGetHeight(upBgView.bounds)];

    [self.myTableView addSubview:upBgView];

    self.myTableView.contentInset = UIEdgeInsetsMake(-kHigher_iOS_6_1_DIS(), , , );//缩进

    self.myTableView.tableFooterView=[self customFooterView];//方法 返回view，看第五点

    self.myTableView.tableHeaderView = [self customHeaderView];

扩展：

UITableViewCellSelectionStyle选择行的样式UITableViewCellSelectionStyleNone,UITableViewCellSelectionStyleBlue,UITableViewCellSelectionStyleGray

如果要自定义cell的背景色

cell.selectedBackgroundView = [[[UIView alloc] initWithFrame:cell.frame]];

cell.selectedBackgroundView.backgroundColor = [UIColor redColor];

改变换行线颜色 tableView.separatorColor = [UIColor blueColor];

- (UIView *)customHeaderView{

    UIView *headerV = [[UIView alloc] initWithFrame:CGRectMake(, , kScreen_Width, )];

    UIImageView *loginLogo = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"login_logo"]];

    CGFloat loginLogoHeight = CGRectGetHeight(loginLogo.bounds)*kScreen_Width/CGRectGetWidth(loginLogo.bounds);

    if (loginLogoHeight > ) {

        [headerV setHeight:loginLogoHeight];

    }

    loginLogo.frame = CGRectMake(, , kScreen_Width, loginLogoHeight);

    [headerV addSubview:loginLogo];

    return headerV;

}

- (UIView *)customFooterView{

    UIView *footerV = [[UIView alloc] initWithFrame:CGRectMake(, , kScreen_Width, )];

    _loginBtn = [UIButton buttonWithStyle:StrapSuccessStyle andTitle:@"登录" andFrame:CGRectMake(, kScreen_Width > ? : , kScreen_Width-*, ) target:self action:@selector(sendLogin)];

    [footerV addSubview:_loginBtn];

    return footerV;

}

- (void)viewDidLoad

{

    [super viewDidLoad];

    [self.navigationController setNavigationBarHidden:YES];

}

typedef struct {

    CGFloat top, left, bottom, right;

} UIEdgeInsets;

主要是理解下UIEdgeInsets在IOS UI里的意义.

UIEdgeInsets==>这货其实就是插入间隔区域。正值表示间隔值，负值表示超出参照物的距离。

1     UIImage* img=[UIImage imageNamed:@"2.png"];//原图
2     UIEdgeInsets edge=UIEdgeInsetsMake(0, 10, 0,10);
3     //UIImageResizingModeStretch：拉伸模式，通过拉伸UIEdgeInsets指定的矩形区域来填充图片
4     //UIImageResizingModeTile：平铺模式，通过重复显示UIEdgeInsets指定的矩形区域来填充图
5     img= [img resizableImageWithCapInsets:edge resizingMode:UIImageResizingModeStretch];
6     self.imageView.image=img;

可以告知用户有一个操作正在进行中。派生自UIView，所以他是视图，也可以附着在视图上。

UIActivityIndicatorView* activityIndicatorView = [ [ UIActivityIndicatorView alloc ]
initWithFrame:CGRectMake(250.0,20.0,30.0,30.0)];

设置风格：

activityIndicatorView.activityIndicatorViewStyle= UIActivityIndicatorViewStyleGray;

UIActivityIndicatorViewStyleWhiteLarge 大型白色指示器

UIActivityIndicatorViewStyleWhite 标准尺寸白色指示器

UIActivityIndicatorViewStyleGray 灰色指示器，用于白色背景

如果希望指示器停止后自动隐藏，那么要设置hidesWhenStoped属性为YES。默认是YES。设置为NO停止后指示器仍会显示。activityIndicatorView.hidesWhenStoped = NO;

显示：可以将它附着在任何视图上，比如表格单元、或者视图，[ self.view addSubview:activityIndicatorView ]

启动和停止

[ activityIndicatorView startAnimating ];//启动

[ activityIndicatorView stopAnimating ];//停止

判断是否处于运动状态isAnimating

[activityIndicatorView isAnimating]

下面为一段实例代码

_activityIndicator = [[UIActivityIndicatorView alloc]

                                 initWithActivityIndicatorStyle:

                                 UIActivityIndicatorViewStyleGray];

            CGSize captchaViewSize = _captchaView.bounds.size;

            _activityIndicator.hidesWhenStopped = YES;

            [_activityIndicator setCenter:CGPointMake(captchaViewSize.width/, captchaViewSize.height/)];

            [_captchaView addSubview:_activityIndicator];

创建一个user defaults方法有多个，最简单得快速创建方法:

NSUserDefaults *accountDefaults = [NSUserDefaults standardUserDefaults];

添加数据到 user defaults:

[accountDefaults setObject:nameField.text forKey:UserDefaultNameKey];

也可以添加基本数据类型int, float, bool等，有相应得方法

[accountDefaults setBool:YES forKey:UserDefaultBoolKey];

从user defaults中获取数据:

[accountDefaults objectForKey:NCUserDefaultNameKey]  

[accountDefaults boolForKey: UserDefaultBoolKey];

注意：UserDefaults不是立即写入，而是根据时间戳定时的把缓存中的数据写入本地磁盘。所以调用了set方法之后数据有可能还没有写入磁盘应用程序就终止了。可以通过调用synchornize方法强制写入。[[NSUserDefaults standardUserDefaults] synchronize]; 

代码片段：

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

        [defaults setObject:[NSNumber numberWithBool:YES] forKey:kLoginStatus];

        [defaults setObject:loginData forKey:kLoginUserDict];

        [defaults synchronize];