UItextField：

一、UItextField概念：

UItextField通常用于外部数据输入，以实现人机交互。下面以一个简单的登陆界面来讲解UItextField的详细使用。

二、UItextField的初始化：

eg: UITextField *tf = [[UITextField alloc]init];

tf.frame = CGRectMake(100, 100, 200, 50);

tf.delegate = self;

tf.backgroundColor = [UIColor orangeColor];

//更改提示信息内容

tf.placeholder = @"请输入用户名";

//更改return显示效果

/*

UIReturnKeyDefault,        -默认效果

UIReturnKeyGo,            -开始

UIReturnKeyGoogle,        -搜索

UIReturnKeyJoin,          -加入

UIReturnKeyNext,          -下一步

UIReturnKeySearch,        -搜索

UIReturnKeySend,          -发送

UIReturnKeyYahoo,          -日本

UIReturnKeyDone,          -结束

UIReturnKeyEmergencyCall,

*/

tf.returnKeyType = UIReturnKeyDone;

//外观样式

/**

UIKeyboardAppearanceDefault,          // Default apperance for the current input method.

UIKeyboardAppearanceDark NS_ENUM_AVAILABLE_IOS(7_0),

UIKeyboardAppearanceLight NS_ENUM_AVAILABLE_IOS(7_0),

UIKeyboardAppearanceAlert

*/

tf.keyboardAppearance = UIKeyboardAppearanceDefault;

//键盘类型

/**

UIKeyboardTypePhonePad - 电话键盘

UIKeyboardTypeNumberPad - 纯数字

UIKeyboardTypeEmailAddress - email地址键盘

*/

tf.keyboardType = UIKeyboardTypeASCIICapable;

//秘密输入

tf.secureTextEntry = YES;

//清空按键出现的时机

tf.clearButtonMode = UITextFieldViewModeAlways;

/**

UITextBorderStyleNone,        -默认

UITextBorderStyleLine,        -直线框

UITextBorderStyleRoundedRect  -曲线框

*/

tf.borderStyle =  UITextBorderStyleRoundedRect;

//必写

-(BOOL)textFieldShouldReturn:(UITextField *)textField

{

//取消键盘的第一相应，键盘收回

[textField resignFirstResponder];

return YES;

}

//- (BOOL)textFieldShouldClear:(UITextField *)textField

//-(void)textFieldDidEndEditing:(UITextField *)textField

//-(void)textFieldDidBeginEditing:(UITextField *)textField

//-(BOOL)textFieldShouldReturn:(UITextField *)textField

//-(BOOL)textFieldShouldEndEditing:(UITextField *)textField

//-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField

//用来控制输入内容的

//-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string