一、UITextField 光标的位置设置获取

通过给UITextField 加一个拓展

//#import "UITextField+ExtentRange.h"
#import <UIKit/UIKit.h>
 
@interface UITextField (ExtentRange)
 
- (NSRange) selectedRange;
- (void) setSelectedRange:(NSRange) range;
 
@end

// #import "UITextField+ExtentRange.m"

#import "UITextField+ExtentRange.h"
 
@implementation UITextField (ExtentRange)
 
- (NSRange) selectedRange
{
    UITextPosition* beginning = self.beginningOfDocument;
    
    UITextRange* selectedRange = self.selectedTextRange;
    UITextPosition* selectionStart = selectedRange.start;
    UITextPosition* selectionEnd = selectedRange.end;
    
    const NSInteger location = [self offsetFromPosition:beginning toPosition:selectionStart];
    const NSInteger length = [self offsetFromPosition:selectionStart toPosition:selectionEnd];
    
    return NSMakeRange(location, length);
}
 
- (void) setSelectedRange:(NSRange) range  // 备注：UITextField必须为第一响应者才有效
{
    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];
}
 
@end

二、UITextField 禁用复制粘贴功能

参考资料：UITextField 禁用复制粘贴功能

新建一个 UITextField 的分类或者是新建一个继承自UITextField的子类（避免与其他UITextField冲突）。
在分类或子类中重写相应的方法。

方法一 (禁用所有输入框功能按钮)：


-(BOOL)canPerformAction:(SEL)action withSender:(id)sender {
        UIMenuController *menuController = [UIMenuController sharedMenuController];
        if (menuController) {
            [UIMenuController sharedMenuController].menuVisible = NO;
        }
    return NO;
}

方法二（可选择禁用部分功能）：

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
    {
        // 禁用粘贴功能
        if (action == @selector(paste:))
            return NO;
 
        // 禁用选择功能
        if (action == @selector(select:))   
            return NO;   
 
        // 禁用全选功能
        if (action == @selector(selectAll:))   
            return NO;
 
        return [super canPerformAction:action withSender:sender];
    }

方法三，在textfield的UITextFieldDelegate里处理，可以通过条件判断更灵活

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (需要禁用的条件) {
        return NO;
    }
    return YES;
}