This is not as short as the other examples, but takes an entirely different approach to solving this problem. Note, the caret will still begin flush to the left edge but the text will be properly indented when typed/displayed. This works without subclassing if your looking for just a left margin and you are already using UITextFieldDelegate for your text fields. You need to set both the default text attributes and the typing attributes. You set the default text attributes when you create the text field. The typing attributes you need to set in the delegate. If you are also using a placeholder you will want to set that to the same margin as well. Putting it altogether you get something like this.

首先在UITextField类上创建一个类别。

//  UITextField+TextAttributes.h

#import <UIKit/UIKit.h>

@interface UITextField (TextAttributes)

- (void)setIndent:(CGFloat)indent;

@end


//  UITextField+TextAttributes.m
#import "UITextField+TextAttributes.h"

@implementation UITextField (TextAttributes)

- (void)setTextAttributes:(NSDictionary*)textAttributes indent:(CGFloat)indent
{
    if (!textAttributes) return;

    NSMutableParagraphStyle *paragraphStyle = [textAttributes objectForKey:NSParagraphStyleAttributeName];
    paragraphStyle.firstLineHeadIndent = indent;
    paragraphStyle.headIndent = indent;
}

- (void)setIndent:(CGFloat)indent
{
   [self setTextAttributes:self.defaultTextAttributes indent:indent];
   [self setTextAttributes:self.typingAttributes indent:indent];
}

@end

然后，如果您使用放置占位符，请确保使用带有属性的占位符设置相同的缩进。创建一个具有正确属性的默认属性字典，如下所示:

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
paragraphStyle.firstLineHeadIndent = 7;
paragraphStyle.headIndent = 7;
NSDictionary *placeholderAttributes = [NSDictionary dictionaryWithObjectsAndKeys: paragraphStyle, NSParagraphStyleAttributeName, nil];

然后，导入上述类别，每当你创建一个文本字段设置默认缩进，委托和使用默认占位符属性上面定义。例如:

UITextField *textField = [[UITextField alloc] init];
textField.indent = 7;
textField.delegate = self;
textField.attributedPlaceholder = [[NSAttributedString alloc] initWithString:@"Placeholder Text" attributes:placeholderAttributes];

最后，在委托中，实现textFieldDidBeginEditing方法，就像这样:

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    textField.indent = 7;
}

我通常尽量避免子类化，但如果你已经:

// add a property 
@property (nonatomic) UIEdgeInsets edgeInsets;

// and override:

- (CGRect)textRectForBounds:(CGRect)bounds
{
    return [super textRectForBounds:UIEdgeInsetsInsetRect(bounds, self.edgeInsets)];
}

- (CGRect)editingRectForBounds:(CGRect)bounds
{
    return [super editingRectForBounds:UIEdgeInsetsInsetRect(bounds, self.edgeInsets)];
}

我子类化UITextField来处理这个，它支持左，上，右和底部的插入，以及清除按钮的定位。

MRDInsetTextField.h

#import <UIKit/UIKit.h>

@interface MRDInsetTextField : UITextField

@property (nonatomic, assign) CGRect inset;

@end

MRDInsetTextField.m

#import "MRDInsetTextField.h"

@implementation MRDInsetTextField

- (id)init
{
    self = [super init];
    if (self) {
        _inset = CGRectZero;
    }
    return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self) {
        _inset = CGRectZero;
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        _inset = CGRectZero;
    }
    return self;
}

- (void)setInset:(CGRect)inset {
    _inset = inset;

    [self setNeedsLayout];
}

- (CGRect)getRectForBounds:(CGRect)bounds withInset:(CGRect)inset {

    CGRect newRect = CGRectMake(
                         bounds.origin.x + inset.origin.x,
                         bounds.origin.y + inset.origin.y,
                         bounds.origin.x + bounds.size.width - inset.origin.x - inset.size.width,
                         bounds.origin.y + bounds.size.height - inset.origin.y - inset.size.height
                         );

    return newRect;
}

- (CGRect)textRectForBounds:(CGRect)bounds {
    return [self getRectForBounds:[super textRectForBounds:bounds] withInset:_inset];
}

- (CGRect)placeholderRectForBounds:(CGRect)bounds {
    return [self getRectForBounds:bounds withInset:_inset];
}

- (CGRect)editingRectForBounds:(CGRect)bounds {
    return [self getRectForBounds:[super editingRectForBounds:bounds] withInset:_inset];
}

- (CGRect)clearButtonRectForBounds:(CGRect)bounds {
    return CGRectOffset([super clearButtonRectForBounds:bounds], -_inset.size.width, _inset.origin.y/2 - _inset.size.height/2);
}

@end

*_someTextField*来自nib/storyboard视图，带有MRDInsetTextField自定义类的用法示例

[(MRDInsetTextField*)_someTextField setInset:CGRectMake(5, 0, 5, 0)]; // left, top, right, bottom inset

在从UITextField派生的类中，至少重写以下两个方法:

- (CGRect)textRectForBounds:(CGRect)bounds;
- (CGRect)editingRectForBounds:(CGRect)bounds;

如果你没有额外的内容，它可能就像这样简单:

return CGRectInset(bounds , 10, 10);

UITextField提供了几个可以覆盖的定位方法。

抛出另一个不需要子类化的解决方案:

UITextField *txtField = [UITextField new];
txtField.borderStyle = UITextBorderStyleRoundedRect;

// grab BG layer
CALayer *bgLayer = txtField.layer.sublayers.lastObject;
bgLayer.opacity = 0.f;

// add new bg view
UIView *bgView = [UIView new];
bgView.backgroundColor = [UIColor whiteColor];
bgView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
bgView.userInteractionEnabled = NO;

[txtField addSubview: bgView];
[txtField sendSubviewToBack: bgView];

在iOS 7和iOS 8上测试。这两个工作。苹果仍然有可能修改UITextField的层层次结构，把事情搞砸了。

对于那些正在寻找更简单解决方案的人来说。

在UIView中添加UITextField。为了模拟文本框周围的插入，我保持左10像素，宽度比视图小20像素。对于文本框周围的圆角边框，请使用视图的边框

viewBG.layer.cornerRadius = 8.0;
viewBG.layer.borderColor = [UIColor darkGrayColor].CGColor;
viewBG.layer.borderWidth = 1.0;