忍不住copy过来http://www.cnblogs.com/wengzilin/archive/2012/03/13/2393985.html
还有些不错的博客推荐给大家http://blog.csdn.net/leeyehong_self/article/details/7904945
http://blog.csdn.net/tskyfree/article/details/8121915
http://blog.csdn.net/justinjing0612/article/details/7058632

1.UITextField的初始化和设置

  textField = [[UITextField alloc] initWithFrame:CGRectMake(120.0f, 80.0f, 150.0f, 30.0f)]; [textField setBorderStyle:UITextBorderStyleRoundedRect]; //外框类型 textField.placeholder = @"password"; //默认显示的字 textField.secureTextEntry = YES; //密码 textField.autocorrectionType = UITextAutocorrectionTypeNo; textField.autocapitalizationType = UITextAutocapitalizationTypeNone; textField.returnKeyType = UIReturnKeyDone; textField.clearButtonMode = UITextFieldViewModeWhileEditing; //编辑时会出现个修改X textField.delegate = self;

2.要实现的Delegate方法,关闭键盘

  - (BOOL)textFieldShouldReturn:(UITextField *)textField { [self.textField resignFirstResponder]; return YES; } 

3. 可以在UITextField使用下面方法，按return键返回

-(IBAction) textFieldDone:(id) sender
{[textFieldName resignFirstResponder];
}

链接TextField控件的"Did end on exit"
最右侧加图片是以下代码,

    UIImageView *imgv=[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"right.png"]];text.rightView=imgv;text.rightViewMode = UITextFieldViewModeAlways;    

如果是在最左侧加图片就换成:

text.leftView=imgv;
text.leftViewMode = UITextFieldViewModeAlways;
UITextField 继承自 UIControl,此类中有一个属性contentVerticalAlignment
所以想让UITextField里面的text垂直居中可以这样写:
text.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;

查看函数的方法：
按住command键双击进入函数声明
按住alt键双击进入doc文档
///
文本框常用方法:
如何用程序删除文本框中选中的文本

[textView delete: nil];

///

如何限制文本框只能输入数字:

建立NSNumberFormatter的子类，增加这个方法，将formatter链接至文本框。

- (BOOL) isPartialStringValid: (NSString **) partialStringPtrproposedSelectedRange: (NSRangePointer) proposedSelRangePtroriginalString: (NSString *) origStringoriginalSelectedRange: (NSRange) origSelRangeerrorDescription: (NSString **) error
{NSCharacterSet *nonDigits;NSRange newStuff;NSString *newStuffString;nonDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];newStuff = NSMakeRange(origSelRange.location,proposedSelRangePtr->location- origSelRange.location);newStuffString = [*partialStringPtr substringWithRange: newStuff];if ([newStuffString rangeOfCharacterFromSet: nonDigitsoptions: NSLiteralSearch].location != NSNotFound) {*error = @"不是数字";return (NO);} else {*error = nil;return (YES);}}

///

从文本框获取十六进制数据的代码

char singleNumberString[3] = {'\0','\0','\0'};
uint32_t singleNumber = 0;
uint32_t i = 0;NSMutableData *data = [NSMutableData data];//从文本框获取到得数据const char *buf = [[_hexToSendTextField text] UTF8String];//转换为十六进制for(i = 0; i < strlen(buf); i+=2){if(((i+1) < len && isxdigit(buf) && (isxdigit(buf[i+1]))){singleNumberString[0] = buf;singleNumberString[1] = buf[i+1];sscanf(singleNumberString, "%x", &singleNumber);[data appendBytes:(void*)(&tmp) length:1];}else{break;}}//输出NSLog(@"%@", data);

/
点击 UITextView 输入文字，光标都从最初点开始

- (void)textViewDidChangeSelection:(UITextView *)textView
{NSRange range;range.location = 0;range.length = 0;textView.selectedRange = range;
}

///
软键盘
在登录页面要实现用户名和密码，密码要是点点格式，引入当前页面光标要停留在用户名选项，软键盘要弹出界面。如下图：
弹出键盘：

[username becomeFirstResponder];

取消键盘：

[username resignFirstResponder];

密码保护：

password.secureTextEntry=YES;

//

1.UITextField的初始化和设置

 textField = [[UITextField alloc] initWithFrame:CGRectMake(120.0f, 80.0f, 150.0f, 30.0f)];
[textField setBorderStyle:UITextBorderStyleRoundedRect]; //外框类型
textField.placeholder = @"password"; //默认显示的字
textField.secureTextEntry = YES; //密码
textField.autocorrectionType = UITextAutocorrectionTypeNo;
textField.autocapitalizationType = UITextAutocapitalizationTypeNone;
textField.returnKeyType = UIReturnKeyDone;
textField.clearButtonMode = UITextFieldViewModeWhileEditing; //编辑时会出现个修改X
textField.delegate = self;

2.要实现的Delegate方法,关闭键盘

  - (BOOL)textFieldShouldReturn:(UITextField *)textField { [self.textField resignFirstResponder]; return YES; } 

3. 可以在UITextField使用下面方法，按return键返回

-(IBAction) textFieldDone:(id) sender
{[textFieldName resignFirstResponder];
}

链接TextField控件的"Did end on exit"

限制输入文本的长度

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{if (range.location >= MAX_LENGTH)return NO; // return NO to not change textreturn YES;
}
if (textField.text.length >= 10 && range.length == 0)return NO;
return YES;
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{ if ([textField.text length] > MAXLENGTH) { textField.text = [textField.text substringToIndex:MAXLENGTH-1]; return NO; } return YES;
} 

//
使用UITextFieldDelegate来隐藏键盘
在iPhone界面上，时常会需要当用户输入完内容后，隐藏键盘。 当然有很多方法，今天只介绍使用UITextFieldDelegate这个协议实现隐藏键盘。
其实很简单， 需要三步：

1. 在你的控制器类中，加入UITextFieldDelegate这个协议

如：@interface AddItemViewController : UIViewController

2. 在使用了UITextFieldDelegate协议的控制器类的实现中，加入- (BOOL)textFieldShouldReturn:方法。

- (BOOL)textFieldShouldReturn:(UITextField *)textField {[textField resignFirstResponder];return YES;
}

//设置焦点：

[UITextField becomeFirstResponder];

3. 将xib文件中的TextField控件的delegate变量指向到之前使用UITextFieldDelegate协议的那个控制器类,将 TextField的delegate IBOutlet变量右键链接到前面的控制器类的实例上。或者使用代码方式，指定相关TextField的delegate变量。

- (void)viewDidLoad {[super viewDidLoad];itemNameField.delegate = self;priceField.delegate = self;}