四大传值详解:属性传值,单例传值,代理传值,block传值
#import "SecondViewController.h"
@interface FirstViewController ()
@end
@implementation FirstViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor cyanColor];
// 配置导航栏标题
self.navigationItem.title = @"FirstVC";
// 创建导航栏右侧按钮
[self customRightItem];
// 创建textField
[self customTextField];
}
#pragma mark - 创建textField控件方法
- (void)customTextField{
// 创建控件
self.textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 120, 40)];
_textField.borderStyle = UITextBorderStyleRoundedRect;
[self.view addSubview:_textField];
[_textField release];
}
#pragma mark - 创建导航栏右侧按钮
- (void)customRightItem{
UIBarButtonItem *rightItem = [[UIBarButtonItem alloc]initWithTitle:@"跳转" style:UIBarButtonItemStyleDone target:self action:@selector(handleRight:)];
self.navigationItem.rightBarButtonItem = rightItem;
[rightItem release];
}
#pragma mark - 导航栏右侧按钮关联方法
- (void)handleRight:(UIBarButtonItem *)sender{
// 创建跳转到的页面视图
SecondViewController *secondVC = [[SecondViewController alloc]init];
// 属性传值第二步
// 在push之前将_textField的值取出来赋值给secondVC.textString
// secondVC.textString = _textField.text;
[secondVC release];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
@interface SecondViewController : UIViewController
// 属性传值第一步
@property (nonatomic,copy)NSString *textString;
@interface SecondViewController ()
@end
@implementation SecondViewController
- (void)dealloc
{
self.textString = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor lightGrayColor];
// 配置导航栏标题
self.navigationItem.title = @"SecondVC";
// 创建label
[self customLabel];
// 属性传值第三步
// 将属性中存储的值取出来赋值给_label.text
_label.text = _textString;
}
#pragma mark - 创建label方法
- (void)customLabel{
// 创建label对象
self.label = [[UILabel alloc]initWithFrame:CGRectMake(100,100,120,40)];
_label.layer.cornerRadius = 7;
_label.backgroundColor = [UIColor cyanColor];// label默认透明,需要赋颜色
[self.view addSubview:_label];
[_label release];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
// 单例:使用我们自己设计的创建方法,无论在任何地方调用这个方法保证返回的是同一个对象,这个类就叫做单例类
// 注意:单例类不能使用alloc init 创建对象
// 单例的缺点:它所占的堆区的内存永远都不会释放,除非退出程序,所以单例中储存过大的数据
@interface Singleton : NSObject
// 单例传值的第一步:设计单例的创建方法,设计为类方法,方法有返回值,返回值就是在方法内部创建对象
// 单例创建的开头一般都是:share, main, default, stand
+ (Singleton *)shareSingleton;
// 单例传值的第二步:根据要传数据,设置属性
@property (nonatomic,copy)NSString *string;
@implementation Singleton
+ (Singleton *)shareSingleton{
// 创建一个静态区对象指针,保障它的生命周期和程序一样悠长
// static修饰的变量,初始化方法只走一次
static Singleton *singleton = nil;
if (singleton == nil) {
// 这个对象不能释放
singleton = [[Singleton alloc]init];
}
return singleton;
}
#import "Singleton.h"
@interface FirstViewController ()
@end
@implementation FirstViewController
- (void)dealloc
{
self.textField = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor cyanColor];
// 配置导航栏标题
self.navigationItem.title = @"FirstVC";
// 创建导航栏右侧按钮
[self customRightItem];
// 创建textField
[self customTextField];
}
#pragma mark - 创建textField控件方法
- (void)customTextField{
// 创建控件
self.textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 120, 40)];
_textField.borderStyle = UITextBorderStyleRoundedRect;
[self.view addSubview:_textField];
[_textField release];
}
#pragma mark - 创建导航栏右侧按钮
- (void)customRightItem{
UIBarButtonItem *rightItem = [[UIBarButtonItem alloc]initWithTitle:@"跳转" style:UIBarButtonItemStyleDone target:self action:@selector(handleRight:)];
self.navigationItem.rightBarButtonItem = rightItem;
[rightItem release];
}
#pragma mark - 导航栏右侧按钮关联方法
- (void)handleRight:(UIBarButtonItem *)sender{
// 创建跳转到的页面视图
SecondViewController *secondVC = [[SecondViewController alloc]init];
// 单例传值第三步
[Singleton shareSingleton].string = _textField.text;
[self.navigationController pushViewController:secondVC animated:YES];
[secondVC release];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
@interface SecondViewController : UIViewController
#import "Singleton.h"
@interface SecondViewController ()
@property (nonatomic,retain)UILabel *label;
@end
@implementation SecondViewController
- (void)dealloc
{
self.textString = nil;
self.label = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor lightGrayColor];
// 配置导航栏标题
self.navigationItem.title = @"SecondVC";
// 创建导航栏左侧按钮
[self customLeftItem];
// 创建导航栏右侧按钮
[self customRightItem];
// 创建label
[self customLabel];
// 单例传值第四部
_label.text = [Singleton shareSingleton].string;
}
#pragma mark - 创建label方法
- (void)customLabel{
// 创建label对象
self.label = [[UILabel alloc]initWithFrame:CGRectMake(100,100,120,40)];
_label.layer.cornerRadius = 7;
_label.backgroundColor = [UIColor cyanColor];// label默认透明,需要赋颜色
[self.view addSubview:_label];
[_label release];
}
#pragma mark - 创建导航栏左侧按钮方法
- (void)customLeftItem{
UIBarButtonItem *leftItem = [[UIBarButtonItem alloc]initWithTitle:@"返回" style:UIBarButtonItemStyleDone target:self action:@selector(handleLeft:)];
self.navigationItem.leftBarButtonItem = leftItem;
[leftItem release];
}
#pragma mark - 导航栏左侧点击关联方法
- (void)handleLeft:(UIBarButtonItem *)sender{
[self.navigationController popViewControllerAnimated:YES];
}
#pragma mark - 创建导航栏右侧按钮方法
- (void)customRightItem{
UIBarButtonItem *rightItem = [[UIBarButtonItem alloc]initWithTitle:@"跳转" style:UIBarButtonItemStyleDone target:self action:@selector(handleRightItem:)];
self.navigationItem.rightBarButtonItem = rightItem;
[rightItem release];
}
#pragma mark - 导航栏右侧跳转方法
- (void)handleRightItem:(UIBarButtonItem *)sender{
ThirdViewController *thirdVC = [[ThirdViewController alloc]init];
[self.navigationController pushViewController:thirdVC animated:YES];
[thirdVC release];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
@interface ThirdViewController : UIViewController
#import "Singleton.h"
@interface ThirdViewController ()
@property (nonatomic,retain)UILabel *label;
@end
@implementation ThirdViewController
- (void)dealloc
{
self.label = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor brownColor];
self.navigationItem.title = @"ThinrdVC";
[self customLabel];
// 单例传值
_label.text = [Singleton shareSingleton].string;
}
#pragma mark - 创建label
- (void)customLabel{
self.label = [[UILabel alloc]initWithFrame:CGRectMake(100, 100, 120, 40)];
_label.backgroundColor = [UIColor whiteColor];
[self.view addSubview:_label];
[_label release];
三: 代理传值
#import "SecondViewController.h"
// 代理传值第四步:代理对象所在的类遵循协议
@interface FirstViewController ()<SecondViewControllerDelegate>
@property (nonatomic,retain)UILabel *label;
@end
@implementation FirstViewController
- (void)dealloc
{
self.label = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor cyanColor];
self.navigationItem.title = @"FirstVC";
// 创建label
[self customLabel];
// 创建Button
[self customButton];
}
#pragma mark - 创建label
- (void)customLabel{
self.label = [[UILabel alloc]initWithFrame:CGRectMake(50,100, 220, 40)];
_label.backgroundColor = [UIColor lightGrayColor];
[self.view addSubview:_label];
[_label release];
}
#pragma mark - 创建Button
- (void)customButton{
UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
button.frame = CGRectMake(130, 180, 50, 50);
[button setTitle:@"下一级" forState:UIControlStateNormal];
[self.view addSubview:button];
[button addTarget:self action:@selector(handleButton:) forControlEvents:UIControlEventTouchUpInside];
}
- (void)handleButton:(UIButton *)sender{
SecondViewController *secondVC = [[SecondViewController alloc]init];
// 代理传值第三步:指定代理对象
secondVC.delegate = self;
[self.navigationController pushViewController:secondVC animated:YES];
[secondVC release];
}
// 代理传值第五步:实现协议方法
- (void)passValue:(NSString *)string{
_label.text = string;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
@protocol SecondViewControllerDelegate <NSObject>
// 代理传值第一步:制订协议
@optional
// 根据要传的数据类型设计方法的参数
- (void)passValue:(NSString *)string;
@end
@interface SecondViewController : UIViewController
// 代理传值第二步:定义代理协议属性
@property (nonatomic,assign)id <SecondViewControllerDelegate>delegate;
@interface SecondViewController ()
@property (nonatomic,retain)UITextField *textField;
@end
@implementation SecondViewController
- (void)dealloc
{
self.textField = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor orangeColor];
self.navigationItem.title = @"SecondVC";
// 创建texField
[self customTextField];
// 创建导航左边按钮
[self customLeft];
}
#pragma mark - 创建texField
- (void)customTextField{
self.textField = [[UITextField alloc]initWithFrame:CGRectMake(50, 100, 220, 40)];
_textField.backgroundColor = [UIColor whiteColor];
[self.view addSubview:_textField];
[_textField release];
}
#pragma mark - 创建导航左边按钮
- (void)customLeft{
UIBarButtonItem *leftItem = [[UIBarButtonItem alloc]initWithTitle:@"返回上一级" style:UIBarButtonItemStyleDone target:self action:@selector(handleLftItem:)];
self.navigationItem.leftBarButtonItem = leftItem;
[leftItem release];
}
- (void)handleLftItem:(UIBarButtonItem *)sender{
// 代理传值第六步:在pop之前通知代理对象执行协议中的方法
// 判断代理对象有没有实现协议中的方法
if ([_delegate respondsToSelector:@selector(passValue:)]) {
[_delegate passValue:_textField.text];
}
[self.navigationController popViewControllerAnimated:YES];
#import "SecondViewController.h"
@interface FirstViewController ()
@property (nonatomic,retain)UILabel *label;
@end
@implementation FirstViewController
- (void)dealloc
{
self.label = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor cyanColor];
self.navigationItem.title = @"FirstVC";
// 创建label
[self customLabel];
// 创建Button
[self customButton];
}
#pragma mark - 创建label
- (void)customLabel{
self.label = [[UILabel alloc]initWithFrame:CGRectMake(50,100, 220, 40)];
_label.backgroundColor = [UIColor lightGrayColor];
[self.view addSubview:_label];
[_label release];
}
#pragma mark - 创建Button
- (void)customButton{
UIButton *button = [UIButton buttonWithType:UIButtonTypeSystem];
button.frame = CGRectMake(130, 180, 50, 50);
[button setTitle:@"下一级" forState:UIControlStateNormal];
[self.view addSubview:button];
[button addTarget:self action:@selector(handleButton:) forControlEvents:UIControlEventTouchUpInside];
}
- (void)handleButton:(UIButton *)sender{
SecondViewController *secondVC = [[SecondViewController alloc]init];
// block传值第三步:给block属性赋值,存储一段代码块,在合适的时机回调block内所传的值
secondVC.block = ^(NSString *string){
_label.text = string;
};
[self.navigationController pushViewController:secondVC animated:YES];
[secondVC release];
// block传值第一步:给block数据类型起别名
typedef void (^BlockName)(NSString *);
@interface SecondViewController : UIViewController
// block传值第二步:定义block属性
@property (nonatomic,copy)BlockName block;
@interface SecondViewController ()
@property (nonatomic,retain)UITextField *textField;
@end
@implementation SecondViewController
- (void)dealloc
{
self.textField = nil;
[super dealloc];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor orangeColor];
self.navigationItem.title = @"SecondVC";
// 创建texField
[self customTextField];
// 创建导航左边按钮
[self customLeft];
}
#pragma mark - 创建texField
- (void)customTextField{
self.textField = [[UITextField alloc]initWithFrame:CGRectMake(50, 100, 220, 40)];
_textField.backgroundColor = [UIColor whiteColor];
[self.view addSubview:_textField];
[_textField release];
}
#pragma mark - 创建导航左边按钮
- (void)customLeft{
UIBarButtonItem *leftItem = [[UIBarButtonItem alloc]initWithTitle:@"返回上一级" style:UIBarButtonItemStyleDone target:self action:@selector(handleLftItem:)];
self.navigationItem.leftBarButtonItem = leftItem;
[leftItem release];
}
- (void)handleLftItem:(UIBarButtonItem *)sender{
// block传值第四步:block属性的调用(类似于代理传值中的通知代理对象实现协议方法过程)
_block(_textField.text);
[self.navigationController popViewControllerAnimated:YES];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
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