给UITextField设置头或尾空白

有时候，我们需要在UITextField的头尾加入一些空白，如下图所示：

其中，黄色和红色部分代表空白。

实现起来，比较简单，只需要设置UITextField的leftView、leftViewMode和rightView、rightViewMode即可，代码如下：

假设现有UItextField * txtField；

    UIView * rView =[[UIView alloc] initWithFrame:CGRectMake(txtField.frame.size.width - 10, 0, 10, txtField.frame.size.height)];
    rView.backgroundColor = [UIColor redColor];
    txtField.rightView = rView;
    txtField.rightViewMode = UITextFieldViewModeAlways;

    UIView * view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, txtField.frame.size.height)];
    view.backgroundColor = [UIColor yellowColor];
    txtField.leftViewMode = UITextFieldViewModeAlways;
    txtField.leftView = view;