有的时候，使用iOS自带的控件不符合变态产品狗的需求时，我们只好自定义控件来满足他们。在此处，我们通过创建一个GUSearchBar类，继承自UITextField类来自定义搜索框。

创建GUSearchBar

代码如下：GUSearchBar.h

#import <UIKit/UIKit.h>
@interface GUSearchBar : UITextField
+(instancetype) searchBar;
@end

GUSearchBar.m

#import "GUSearchBar.h"
@implementation GUSearchBar
-(id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.background = [UIImage resizedImage:@"searchbar_textfield_background"];
        self.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
        UIImageView *leftView = [[UIImageView alloc] init];
        leftView.image = [UIImage imageWithName:@"searchbar_textfield_search_icon"];
        leftView.width = leftView.image.size.width + 10;
        leftView.height = leftView.image.size.height;
        leftView.contentMode = UIViewContentModeCenter;
        self.leftView = leftView;
        self.leftViewMode = UITextFieldViewModeAlways;
        self.clearButtonMode = UITextFieldViewModeAlways;
        self.placeholder = @"搜索";
    }
    return self;
}
+(instancetype) searchBar
{
    return [[self alloc] init];
}
@end

注意：上述有类似leftView.width，leftView.height这样的语法是使用了自定义UIView的扩展分类，详情请点击UIView扩展。

使用

GUSearchBar *searchBar = [[GUSearchBar alloc] init];
searchBar.width = 350;
searchBar.height = 30;
self.navigationItem.titleView = searchBar;

使用效果