常用方法

UITextFieldDelegate

self.textField = ({
    UITextField * textField = [UITextField new];
    textField.delegate = self;
    textField.clearButtonMode = UITextFieldViewModeWhileEditing;
    textField.keyboardType = UIKeyboardTypeDefault;
    textField.placeholder = @"请输入";
    textField.font = [UIFont systemFontOfSize:12];
    textField.borderStyle = UITextBorderStyleNone;
    [self.view addSubview: textField];

textField

});

//开始编辑时触发，文本字段将成为first responder
-(void)textFieldDidBeginEditing:(UITextField *)textField {

}

//是否允许文本字段结束编辑
-(BOOL)textFieldShouldEndEditing:(UITextField *)textField {
return NO;
}

//当用户使用自动更正功能，把输入的文字修改为推荐的文字时，就会调用这个方法。
-(BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
return YES;
}

//是否允许清除内容
-(BOOL)textFieldShouldClear:(UITextField *)textField  {
return YES;
}

UITextField 光标的位置获取和设置

//#import "UITextField+ExtentRange.h"

import <UIKit/UIKit.h>

@interface UITextField (ExtentRange)

• (NSRange) selectedRange;
• (void) setSelectedRange:(NSRange) range;
  @end

import "UITextField+ExtentRange.h"

@implementation UITextField (ExtentRange)
光标选择的范围 * * @return
获取光标选择的范围 */

• (NSRange)selectedRange{
  //开始位置UITextPosition* beginning = self.beginningOfDocument;
  //光标选择区域UITextRange* selectedRange = self.selectedTextRange;
  //选择的开始位置UITextPosition* selectionStart = selectedRange.start;
  //选择的结束位置UITextPosition* selectionEnd = selectedRange.end;
  //选择的实际位置constNSInteger location = [self offsetFromPosition:beginning toPosition:selectionStart];
  //选择的长度constNSInteger length = [self offsetFromPosition:selectionStart toPosition:selectionEnd];
  returnNSMakeRange(location, length);
  }
  /** * 设置光标选择的范围* * @param range 光标选择的范围 */
• (void) setSelectedRange:(NSRange) range { UITextPosition* beginning = self.beginningOfDocument; UITextPosition* startPosition = [self positionFromPosition:beginning offset:range.location]; UITextPosition* endPosition = [self positionFromPosition:beginning offset:range.location + range.length]; UITextRange* selectionRange = [self textRangeFromPosition:startPosition toPosition:endPosition]; [self setSelectedTextRange:selectionRange]; }

限制输入字数：代码如下：
用的都是textView的delegate的方法:

• (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
  if(range.location > 100){
  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示"
  message:@"输入的自字符数不能超过300"
  delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];
  [alert show];
  [alert release];
  return NO;
  }else{
  NSLog(@"%d",textView.text.length);
  return YES;
  }
  }
  2,显示剩余可输入字数,代码如下:

• (void)textViewDidChange:(UITextView *)textView{
  int count;
  count = shuzi - textView.text.length;
  [_wordCount setText:[NSString stringWithFormat:@"%d", count]]; //_wordCount是一个显示剩余可输入数字的label
  }