我发现了罗伯托发布的选项。buratti是最快的解决方案，这里是Swift:

let leftView = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: textField.frame.size.height))
leftView.backgroundColor = textField.backgroundColor
textField.leftView = leftView
textField.leftViewMode = UITextField.ViewMode.always

如果你想改变TOP和LEFT缩进只有这样

//占位符

- (CGRect)textRectForBounds:(CGRect)bounds {

CGRect frame = bounds;
frame.origin.y = 3;
 frame.origin.x = 5;
bounds = frame;
return CGRectInset( bounds , 0 , 0 );
}

//文本位置

- (CGRect)editingRectForBounds:(CGRect)bounds {

CGRect frame = bounds;
frame.origin.y = 3;
 frame.origin.x = 5;
bounds = frame;
return CGRectInset( bounds , 0 , 0 );
}

你可以通过使文本字段成为UITextField的子类并覆盖-textRectForBounds:方法来调整文本在文本字段中的位置。

你必须子类化是荒谬的，因为UITextField已经实现了方法，就像@Adam Waite指出的那样。下面是一个快速扩展，它公开了一个工厂方法，也可以在我们的categories repo中使用:

private class InsetTextField: UITextField {
    var insets: UIEdgeInsets

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

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

    // placeholder position
    override func textRectForBounds(bounds: CGRect) -> CGRect {
        return super.textRectForBounds(UIEdgeInsetsInsetRect(bounds, insets))
    }

    // text position
    override func editingRectForBounds(bounds: CGRect) -> CGRect {
        return super.editingRectForBounds(UIEdgeInsetsInsetRect(bounds, insets))
    }
}

extension UITextField {

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

}

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
    }()

}

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;