懒加载

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

    // Override point for customization after application launch.

    self.window.backgroundColor = [UIColor whiteColor];

    

    

    RootViewController *rootVC = [[RootViewController alloc] init];

    self.window.rootViewController = rootVC;

    [rootVC release];

    

    [self.window makeKeyAndVisible];

    return YES;

}

 

#import "RootViewController.h"

 

@interface RootViewController ()

 

@property (nonatomic, retain) UILabel *label;

@property (nonatomic, retain) UITextField *textField;

@property (nonatomic, retain) UIView *myView;

 

@end

 

@implementation RootViewController

 

- (void)dealloc {

    [_myView release];

    [super dealloc];

}

 

//懒加载

- (UILabel *)label {

    if (_label == nil) {

        _label = [[UILabel alloc] initWithFrame:CGRectMake(100, 200, 200, 40)];

        _label.text = @"中二洪荒巴达";

        _label.textAlignment = NSTextAlignmentCenter;

    }

    return _label;

}

 

- (UITextField *)textField {

    if (_textField == nil) {

        _textField = [[UITextField alloc] initWithFrame:CGRectMake(100, 200, 200, 40)];

        _textField.borderStyle = UITextBorderStyleRoundedRect;

        _textField.placeholder = @"输入框";

    }

    return _textField;

}

 

- (void)viewDidLoad {

    [super viewDidLoad];

    

    /*

    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"1" ofType:@"jpg"];

    UIImage *image = [UIImage imageWithContentsOfFile:filePath];

    

    NSLog(@"filePath is %@",filePath);

    

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 200, 200, 200)];

    imageView.image = image;

    [self.view addSubview:imageView];

    [imageView release];

    

    UISwitch *mySwitch = [[UISwitch alloc] initWithFrame:CGRectMake(100, 100, 0, 0)];

    [self.view addSubview:mySwitch];

    [mySwitch addTarget:self action:@selector(switchAction:) forControlEvents:UIControlEventValueChanged];

    

    [mySwitch release];*/

    

    UISegmentedControl *seg = [[UISegmentedControl alloc] initWithItems:@[@"label", @"textField"]];

    seg.frame = CGRectMake(50, 100, 275, 40);

    

    [seg addTarget:self action:@selector(segmentedControlAction:) forControlEvents:UIControlEventValueChanged];

//    seg.selectedSegmentIndex = 0;

    [self.view addSubview:seg];

    [seg release];

    

    _myView = [[UIView alloc] initWithFrame:CGRectMake(0, 200, 375, 400)];

    [self.view addSubview:_myView];

    

    

    // Do any additional setup after loading the view.

}

 

- (void)segmentedControlAction:(UISegmentedControl *)seg {

    switch (seg.selectedSegmentIndex) {

        case 0:

            [[self.myView.subviews firstObject] removeFromSuperview];

 

            [self.myView addSubview:self.label];

 

            

            break;

        case 1:

            [[self.myView.subviews firstObject] removeFromSuperview];

 

            [self.myView addSubview:self.textField];

            break;

        default:

            break;

    }

}

 

- (void)switchAction:(UISwitch *)mySwitch {

    if (mySwitch.on) {

        NSLog(@"开启");

    } else {

        NSLog(@"关闭");

    }

}

 

 

 

 

 

转载于:https://www.cnblogs.com/wwww543623/p/5171240.html