缩进UITextField中的文本

我的问题和标题一样简单，但还有更多一点：

我有一个UITextField，在上面设置了背景图片。问题在于文本紧靠其边缘（也就是图像的边缘）。我希望我的文本字段看起来像Apple的文本字段，在背景图像和文本的起始位置之间留出一定的水平空间。

这是我不做任何子类就发现的最快方法：

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

在Swift中：

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

您必须继承并重写textRectForBounds：和editRectForBounds:。这是一个具有自定义背景以及垂直和水平填充的UITextfield子类：

@interface MyUITextField : UITextField 
@property (nonatomic, assign) float verticalPadding;
@property (nonatomic, assign) float horizontalPadding;
@end

#import "MyUITextField.h"
@implementation MyUITextField
@synthesize horizontalPadding, verticalPadding;
- (CGRect)textRectForBounds:(CGRect)bounds {
    return CGRectMake(bounds.origin.x + horizontalPadding, bounds.origin.y + verticalPadding, bounds.size.width - horizontalPadding*2, bounds.size.height - verticalPadding*2);
}
- (CGRect)editingRectForBounds:(CGRect)bounds {
    return [self textRectForBounds:bounds];
}
@end

用法：

UIImage *bg = [UIImage imageNamed:@"textfield.png"];
CGRect rect = CGRectMake(0, 0, bg.size.width, bg.size.height);
MyUITextField *textfield = [[[MyUITextField alloc] initWithFrame:rect] autorelease];
textfield.verticalPadding = 10; 
textfield.horizontalPadding = 10;
[textfield setBackground:bg];
[textfield setBorderStyle:UITextBorderStyleNone];
[self.view addSubview:textfield];

向UITextField添加填充的一种好方法是子类UITextField，重写矩形方法并添加edgeInsets属性。然后可以设置edgeInsets，并相应地绘制UITextField。使用自定义的leftView或rightView集也可以正常运行。

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

我把它变成了一个很好的小扩展，可以在Storyboard中使用：

public extension UITextField {
    @IBInspectable public var leftSpacer:CGFloat {
        get {
            return leftView?.frame.size.width ?? 0
        } set {
            leftViewMode = .Always
            leftView = UIView(frame: CGRect(x: 0, y: 0, width: newValue, height: frame.size.height))
        }
    }
}

我的2美分：

class PaddedTextField : UITextField {
    var insets = UIEdgeInsets.zero
    var verticalPadding:CGFloat = 0
    var horizontalPadding:CGFloat = 0

    override func textRect(forBounds bounds: CGRect) -> CGRect {
        return CGRect(x: bounds.origin.x + insets.left, y: bounds.origin.y + insets.top, width: bounds.size.width - (insets.left + insets.right), height: bounds.size.height - (insets.top + insets.bottom));
    }

    override func editingRect(forBounds bounds: CGRect) -> CGRect {
        return textRect(forBounds: bounds)
    }
}

建议您将转换UITextField为UITextView并设置contentInset。例如缩进10个空格：

textview.contentInset=UIEdgeInsetsMake(0, 10, 0, 0);

有时，textField的leftView是Apple的放大镜图像。如果是这样，您可以像这样设置缩进：

    UIView *leftView = textField.leftView;
    if (leftView && [leftView isKindOfClass:[UIImageView class]]) {
        leftView.contentMode = UIViewContentModeCenter;
        leftView.width = 20.0f;  //the space you want indented.
    }

如果您不想创建@IBOutlet，可以简单地子类化（在Swift中为答案）：

class PaddedTextField: UITextField {

  override func awakeFromNib() {
      super.awakeFromNib()

      let spacerView = UIView(frame:CGRect(x: 0, y: 0, width: 10, height: 10))
      leftViewMode = .always
      leftView = spacerView
   }
}