【iOS開發】添加子控制項方式(懶載入，GCC)

標籤：

 1 // 2 //  ViewController.m 3 //  GCC 4 // 5 //  Created by admin on 15/10/7. 6 //  Copyright © 2015年 admin. All rights reserved. 7 // 8  9 #import "ViewController.h"10 11 @interface ViewController ()12 13 @property (nonatomic, strong) UIButton* btn;14 15 @property (nonatomic, strong) UIButton* blueButton;16 17 @end18 19 @implementation ViewController20 21 - (void)viewDidLoad22 {23     [super viewDidLoad];24 25     UIButton* btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];26     btn.backgroundColor = [UIColor redColor];27 28     [self.view addSubview:btn];29     [self.view addSubview:self.btn];30     [self.view addSubview:self.blueButton];31 }32 33 ///  GCC34 - (UIButton*)blueButton35 {36     if (!_blueButton) {37 38         _blueButton = ({39             UIButton* btn = [[UIButton alloc] initWithFrame:({40                                                   CGRect frame = CGRectMake(100, 400, 100, 100);41                                                   frame;42                                               })];43             btn.backgroundColor = [UIColor blueColor];44             btn;45         });46     }47     return _blueButton;48 }49 50 ///  懶載入的方式51 - (UIButton*)btn52 {53     if (_btn == nil) {54         _btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 200, 100, 100)];55         _btn.backgroundColor = [UIColor greenColor];56     }57 58     return _btn;59 }60 61 @end

 

【iOS開發】添加子控制項方式(懶載入，GCC)