有的時候，使用iOS自帶的控制元件不符合變態產品狗的需求時，我們只好自定義控制元件來滿足他們。在此處，我們通過建立一個GUSearchBar類，繼承自UITextField類來自定義搜尋框。

建立GUSearchBar

程式碼如下：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 = @"搜尋";
    }
    return self;
}

+(instancetype) searchBar
{
    return [[self alloc] init];
}

@end

注意：上述有類似leftView.width，leftView.height這樣的語法是使用了自定義UIView的擴充套件分類，詳情請點選UIView擴充套件。

使用

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

self.navigationItem.titleView = searchBar;

使用效果