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;
}

Swift 5版本的克里斯托弗的答案与额外的用法示例

import UIKit

private class InsetTextField: UITextField {
    var insets: UIEdgeInsets

    init(insets: UIEdgeInsets) {
        self.insets = insets
        super.init(frame: .zero)
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("not intended for use from a NIB")
    }

    // placeholder position
    override func textRect(forBounds bounds: CGRect) -> CGRect {
         return super.textRect(forBounds: bounds.inset(by: insets))
    }
 
    // text position
    override func editingRect(forBounds bounds: CGRect) -> CGRect {
         return super.editingRect(forBounds: bounds.inset(by: insets))
    }
}

extension UITextField {

    class func textFieldWithInsets(insets: UIEdgeInsets) -> UITextField {
        return InsetTextField(insets: insets)
    }

}

用法:-

class ViewController: UIViewController {

  private let passwordTextField: UITextField = {

        let textField = UITextField.textFieldWithInsets(insets: UIEdgeInsets(top: 10, left: 15, bottom: 10, right: 15))
     // ---
   
        return textField
    }()

}

斯威夫特

    // adjust place holder text
    let paddingView = UIView(frame: CGRectMake(0, 0, 10, usernameOrEmailField.frame.height))
    usernameOrEmailField.leftView = paddingView
    usernameOrEmailField.leftViewMode = UITextFieldViewMode.Always

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。

解决方案:实际有效且适用于所有情况的解决方案:

应该使用offsetBy而不是insetBy。 也应该调用超函数来获取原始的Rect。 Bounds故障。你需要抵消原来的X, Y，边界有X, Y为零。 原始的x, y可以是非零，例如当设置UITextField的leftView时。

示例:

override func textRect(forBounds bounds: CGRect) -> CGRect {
    return super.textRect(forBounds: bounds).offsetBy(dx: 0.0, dy: 4)
}


override func editingRect(forBounds bounds: CGRect) -> CGRect {
    return super.editingRect(forBounds: bounds).offsetBy(dx: 0.0, dy: 4)
}

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;
}