iOS UITextField的属性、代理及通知

一、UITextField通知（UITextField文本发生变化会调用通知）

 初始化一个(连线)UITextField控件

@property (weak, nonatomic) IBOutlet UITextField *pwdField;

在viewDidLoad初始化通知

//注意name和object的设定值
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChange) name:UITextFieldTextDidChangeNotification object:self.pwdField];

实现通知方法

/**
 *  文本框的文字发生改变的时候调用
 */
- (void)textChange
{
    //在这里面当self.pwdFiled控件文字发生变化就会掉用这个通知方法。
}

二、UITextField的代理方法

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField;        // return NO to disallow editing.
- (void)textFieldDidBeginEditing:(UITextField *)textField;           // became first responder
- (BOOL)textFieldShouldEndEditing:(UITextField *)textField;          // return YES to allow editing to stop and to resign first responder status. NO to disallow the editing session to end
- (void)textFieldDidEndEditing:(UITextField *)textField;             // may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;   // return NO to not change text

- (BOOL)textFieldShouldClear:(UITextField *)textField;               // called when clear button pressed. return NO to ignore (no notifications)
- (BOOL)textFieldShouldReturn:(UITextField *)textField;              // called when 'return' key pressed. return NO to ignore.

三、UITextField的属性

//创建UITextField对象
UITextField * YM=[[UITextField alloc]init];

//设置文字
YM.title=@"欲眠";

//设置UITextField的文字颜色
YM.textColor=[UIColor redColor];

//设置UITextField的文本框背景颜色
YM.backgroundColor=[UIColor grayColor];

//设置UITextField的边框的风格
YM.borderStyle=UITextBorderStyleRoundedRect;

//设置UITextField的代理
YM.delegate=self;

//设置UITextField的文字对齐方式
YM.textAlignment=UITextAlignmentCenter;//居中对齐
YM.textAlignment=UITextAlignmentLeft;//左对齐
YM.textAlignment=UITextAlignmentRight;//右对齐
YM.textAlignment=UITextAlignmentFill;//填充对齐

//设置UITextField的文字大小和字体
YM.font=[UIFont fontWithName:@"Times New Roman" size:20];

//设置UITextField自适应文本框大小
YM.adjustsFontSizeToFitWidth=YES/NO;//自适应宽度
YM.adjustsFontSizeToFitHeight=YES/NO;//自适应高度

//设置UITextField是否拥有一键清除的功能
YM.clearsOnBeginEditing=YES/NO;

//设置一键清除按钮是否出现
YM.clearButtonMode=UITextFieldViewModeNever;

//设置UITextField的初始隐藏文字
YM.placeholder=@"输入密码";

//当UITextField的样式为UITextBorderStyleNone的时候，修改背景图片
YM.background=[UIImage imageNamed:@"xx.png"];

//设置UITextField的左边view
YM.leftView=xxx;

//设置UITextField的左边view出现模式
YM.leftViewMode=UITextFieldViewModeAlways;

//设置UITextField的右边view
YM.rightView=xxx;

//设置UITextField的右边view出现模式
YM.rightViewMode=UITextFieldViewModeAlways;

//设置UITextField的字的摆设方式
YM.contentVerticalAlignment=UIControlContentVerticalAlignmentCenter;