如何在UITextField leftView图像上获得左边距？

Question

我设立一个UIImageView作为leftView一个UITextField像这样:

UIImageView *envelopeView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.height*.1, self.height*.1)];
envelopeView.image = [UIImage imageNamed:@"envelope.png"];
envelopeView.contentMode = UIViewContentModeScaleAspectFit;
envelopeView.bounds = CGRectInset(envelopeView.frame, 15, 10);
self.emailAddress.leftView = envelopeView;
self.emailAddress.leftViewMode = UITextFieldViewModeAlways;

这让我得到以下:

正如您所看到的那样,即使我尝试设置插图,图像的左侧大小也会一直向上移动到按钮的左边缘.如何移动这个信封,使其四面都有填充物？

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更新:我尝试了改变UIImageView框架的建议答案,但是信封仍然排列在左边的边界UITextField:

CGFloat padding = 20;
UIImageView *envelopeView = [[UIImageView alloc] initWithFrame:CGRectMake(3*padding, padding, self.height*.1-padding, self.height*.1-padding)];

Answer 1

对于Swift 3用户

这对我有用:

extension UITextField {

 /// set icon of 20x20 with left padding of 8px 
 func setLeftIcon(_ icon: UIImage) {

    let padding = 8
    let size = 20

    let outerView = UIView(frame: CGRect(x: 0, y: 0, width: size+padding, height: size) )
    let iconView  = UIImageView(frame: CGRect(x: padding, y: 0, width: size, height: size))
    iconView.image = icon
    outerView.addSubview(iconView)

    leftView = outerView
    leftViewMode = .always  
  }
}

测试:

txOrigin.setLeftIcon(icon_location)

结果:

Answer 2

你可以简单地试试这个：

    UIImageView *envelopeView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 0, 30, 30)];
    envelopeView.image = [UIImage imageNamed:@"comment-128.png"];
    envelopeView.contentMode = UIViewContentModeScaleAspectFit;
  UIView *test=  [[UIView alloc]initWithFrame:CGRectMake(20, 0, 30, 30)];
    [test addSubview:envelopeView];
    [self.textField.leftView setFrame:envelopeView.frame];
    self.textField.leftView =test;
        self.textField.leftViewMode = UITextFieldViewModeAlways;

Answer 3

对于 Swift 4.2 +

你可以使用这个扩展：

extension UITextField {
    func leftImage(_ image: UIImage?, imageWidth: CGFloat, padding: CGFloat) {
        let imageView = UIImageView(image: image)
        imageView.frame = CGRect(x: padding, y: 0, width: imageWidth, height: frame.height)
        imageView.contentMode = .center
        
        let containerView = UIView(frame: CGRect(x: 0, y: 0, width: imageWidth + 2 * padding, height: frame.height))
        containerView.addSubview(imageView)
        leftView = containerView
        leftViewMode = .always
    }
}