为UITextField添加填充的一个好方法是子类化UITextField并添加一个edgeInsets属性。然后设置edgeInsets和UITextField将相应地绘制。对于自定义的leftView或rightView集，这也能正确地发挥作用。

OSTextField.h

#import <UIKit/UIKit.h>

@interface OSTextField : UITextField

@property (nonatomic, assign) UIEdgeInsets edgeInsets;

@end

OSTextField.m

#import "OSTextField.h"

@implementation OSTextField

- (id)initWithFrame:(CGRect)frame{
    self = [super initWithFrame:frame];
    if (self) {
        self.edgeInsets = UIEdgeInsetsMake(0, 0, 0, 0);
    }
    return self;
}

-(id)initWithCoder:(NSCoder *)aDecoder{
    self = [super initWithCoder:aDecoder];
    if(self){
        self.edgeInsets = UIEdgeInsetsMake(0, 0, 0, 0);
    }
    return self;
}

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

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

@end

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;

我想我可以提供一个快速解决方案

import UIKit

class TextField: UITextField {
    let inset: CGFloat = 10

    // placeholder position
    override func textRectForBounds(bounds: CGRect) -> CGRect {
        return CGRectInset(bounds , inset , inset)
    }

    // text position
    override func editingRectForBounds(bounds: CGRect) -> CGRect {
        return CGRectInset(bounds , inset , inset)
    }

    override func placeholderRectForBounds(bounds: CGRect) -> CGRect {
        return CGRectInset(bounds, inset, inset) 
    }
}

斯威夫特 3+

import UIKit

class TextField: UITextField {
    let inset: CGFloat = 10

    // placeholder position
    override func textRect(forBounds: CGRect) -> CGRect {
        return forBounds.insetBy(dx: self.inset , dy: self.inset)
    }

    // text position
    override func editingRect(forBounds: CGRect) -> CGRect {
        return forBounds.insetBy(dx: self.inset , dy: self.inset)
    }

    override func placeholderRect(forBounds: CGRect) -> CGRect {
        return forBounds.insetBy(dx: self.inset, dy: self.inset)
    }
}

这是我发现的最快的方法，不需要做任何子类:

UIView *spacerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10., 10.)];
[textField setLeftViewMode:UITextFieldViewModeAlways];
[textField setLeftView:spacerView];

迅速:

let spacerView = UIView(frame:CGRect(x:0, y:0, width:10, height:10))
textField.leftViewMode = UITextFieldViewMode.Always
textField.leftView = spacerView

快速解决没有子类&也检查

extension UITextField {
    @IBInspectable var textInsets: CGPoint {
            get {
                return CGPoint.zero
            }
            set {
                layer.sublayerTransform = CATransform3DMakeTranslation(newValue.x, newValue.y, 0);
            }
        }
}

下面是在Swift 3中编写的相同子类UITextField。它与之前的Swift版本有很大的不同，正如你将看到的:

import UIKit

class MyTextField: UITextField
    {
    let inset: CGFloat = 10

    // placeholder position
    override func textRect(forBounds bounds: CGRect) -> CGRect
        {
        return bounds.insetBy(dx: inset, dy: inset)
        }

    // text position
    override func editingRect(forBounds bounds: CGRect) -> CGRect
        {
        return bounds.insetBy(dx: inset, dy: inset)
        }

    override func placeholderRect(forBounds bounds: CGRect) -> CGRect
        {
        return bounds.insetBy(dx: inset, dy: inset)
        }
    }

顺便说一句，如果你只想控制一侧的插入，你也可以像下面这样做。如果你把一个图像放在UITextField的顶部，但你想让它在用户看来是在文本框中，那么这个只调整左边插图的特殊例子就很方便了:

    override func editingRect(forBounds bounds: CGRect) -> CGRect
        {
        return CGRect.init(x: bounds.origin.x + inset, y: bounds.origin.y, width: bounds.width - inset, height: bounds.height)
        }