iOS-常见的页面传值方式
背景：
iOS开发中，页面传值是必不可少的。很多时候，控制器之间的传值是很常见。下面，我总结几种常见的页面传值方式，记录下来，方便以后查看。
预备工作：
准备两个控制器，第一个控制有一个UIButton和一个UILabel，第二个控制器有一个UITextField和一个UIButton。
以下的页面传值都围绕这两个控制器来演示。
代码如下：
#import "OneViewController.h"
#import "TwoViewController.h"
@interface OneViewController ()
/**显示文字的Label*/
@property(nonatomic,strong) UILabel *ZFLabel;
/**跳到第二个控制器的Button*/
@property(nonatomic,strong) UIButton *ZFBtn;
@end
@implementation OneViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
[self setupControls];
}
-(void)ZFBtnAction
{
TwoViewController *twoVC = [[TwoViewController alloc] init];
twoVC.str = @"我是属性传值";
[self presentViewController:twoVC animated:YES completion:^{
}];
}
-(void)setupControls
{
self.ZFLabel = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 200, 40)];
self.ZFLabel.backgroundColor = [UIColor cyanColor];
[self.view addSubview:self.ZFLabel];
self.ZFBtn = [UIButton buttonWithType:UIButtonTypeSystem];
self.ZFBtn.frame = CGRectMake(100, CGRectGetMaxY(self.ZFLabel.frame) + 10, 150, 30);
[self.ZFBtn setTitle:@"跳转到第二个控制器" forState:UIControlStateNormal];
[self.ZFBtn addTarget:self action:@selector(ZFBtnAction) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.ZFBtn];
}
@end#import "TwoViewController.h"
@interface TwoViewController ()
/**输入框*/
@property(nonatomic,strong) UITextField *ZFTextField;
/**回到第一个控制器的Button*/
@property(nonatomic,strong) UIButton *ZFBtn;
@end
@implementation TwoViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
[self setupControls];
}
-(void)ZFBtnAction
{
[self dismissViewControllerAnimated:YES completion:^{
}];
}
-(void)setupControls
{
self.ZFTextField = [[UITextField alloc] initWithFrame:CGRectMake(100, 100, 200, 40)];
self.ZFTextField.borderStyle = UITextBorderStyleRoundedRect;
[self.view addSubview:self.ZFTextField];
self.ZFBtn = [UIButton buttonWithType:UIButtonTypeSystem];
self.ZFBtn.frame = CGRectMake(100, CGRectGetMaxY(self.ZFTextField.frame) + 10, 150, 30);
[self.ZFBtn setTitle:@"回到第一个控制器" forState:UIControlStateNormal];
[self.ZFBtn addTarget:self action:@selector(ZFBtnAction) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:self.ZFBtn];
}
@end一、属性传值
属性传值，顾名思义，在控制器里面定义一个属性，然后把值赋值给该控制器属性。属性传值，常用于正向传值，即一个控制器跳转到另一个控制器时候，把值传递给第二个控制器。
核心代码：
OneViewController控制器：
-(void)ZFBtnAction
{
TwoViewController *twoVC = [[TwoViewController alloc] init];
twoVC.str = @"我是属性传值";
[self presentViewController:twoVC animated:YES completion:^{
}];
}TwoViewController控制器：
self.ZFTextField.text = self.str;二、单例传值
单例传值，就是创建一个单例对象，然后把值付给单例对象的属性。无论在哪个控制器，只要调用这个单例对象，就能获取单例对象属性的值。单例传值，可以用于正向、反向传值。
单例对象：
#import
@interface singleton : NSObject
@property(nonatomic,strong) NSString *str;
/**
获取单例对象
@return 当前对象
*/
+(singleton *)shareInstance;
@end #import "singleton.h"
@implementation singleton
+(singleton *)shareInstance
{
static singleton *zfInstance;
if (!zfInstance) {
zfInstance = [[singleton alloc] init];
}
return zfInstance;
}
@endOneViewController控制器:
-(void)ZFBtnAction
{
TwoViewController *twoVC = [[TwoViewController alloc] init];
singleton *zfInstance = [singleton shareInstance];
zfInstance.str = @"我是单例传值";
[self presentViewController:twoVC animated:YES completion:^{
}];
}TwoViewController控制器：
singleton *zfInstance = [singleton shareInstance];
self.ZFTextField.text = zfInstance.str;三、NSUserDefaults传值
每个应用程序都有一个自己的沙盒，而NSUserDefaults就是存在于沙盒里面，系统已经为我们创建好了，我们只需要直接使用就好。NSUserDefaults可以用于正向、反向传值。
OneViewController控制器：
-(void)ZFBtnAction
{
TwoViewController *twoVC = [[TwoViewController alloc] init];
NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
[ud setObject:@"我是NSUserDefaults传值" forKey:@"ZFKey"];
[ud synchronize];
[self presentViewController:twoVC animated:YES completion:^{
}];
}TwoViewController控制器：
NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
NSString *str = [ud objectForKey:@"ZFKey"];
self.ZFTextField.text = str;四、代理传值
代理传值，是苹果开发中最经典的传值方式，常用语反向传值，即从一个控制器到另一个控制器，再由第二个控制器返回到第一个控制器，并且把值从第二个控制器传回到第一个控制器。代理传值比较麻烦，需要定义委托方、代理，而代理需要遵守协议。
OneViewController控制器：
@interface OneViewController ()
/**显示文字的Label*/
@property(nonatomic,strong) UILabel *ZFLabel;
/**跳到第二个控制器的Button*/
@property(nonatomic,strong) UIButton *ZFBtn;
@end
@implementation OneViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
[self setupControls];
}
-(void)ZFBtnAction
{
TwoViewController *twoVC = [[TwoViewController alloc] init];
twoVC.delegate = self;
[self presentViewController:twoVC animated:YES completion:^{
}];
}
-(void)transmitStr:(TwoViewController *)twoVC str:(NSString *)str
{
self.ZFLabel.text = str;
} TwoViewController控制器：
#import delegate;
@end -(void)ZFBtnAction
{
if ([self.delegate respondsToSelector:@selector(transmitStr:str:)]) {
[self.delegate transmitStr:self str:@"我是代理传值"];
}
[self dismissViewControllerAnimated:YES completion:^{
}];
}五、Block传值
Block传值是苹果推荐的一种传值方式，和代理传值一样，常用语反向传值。Block传值写法比代理传值简单，也是比较流行的一种写法。
OneViewController控制器：
-(void)ZFBtnAction
{
TwoViewController *twoVC = [[TwoViewController alloc] init];
twoVC.ZFBlock = ^(NSString *str) {
self.ZFLabel.text = str;
};
[self presentViewController:twoVC animated:YES completion:^{
}];
}TwoViewController控制器：
#import -(void)ZFBtnAction
{
self.ZFBlock(@"我是block传值");
[self dismissViewControllerAnimated:YES completion:^{
}];
}六、通知传值
在苹果开发中，通知更是常见。我们用不但可以用通知进行传值，还能用通知给其他控制器发送其他信号、消息，比如键盘弹出消息等等。通知传值不但可以一对一，还可以一对多，多对多。
OneViewController控制器:
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
[self setupControls];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(receiveMessage:) name:@"notiTransmitValue" object:nil];
}
-(void)receiveMessage:(NSNotification *)noti
{
self.ZFLabel.text = noti.userInfo[@"key"];
}TwoViewController控制器：
-(void)ZFBtnAction
{
[[NSNotificationCenter defaultCenter] postNotificationName:@"notiTransmitValue" object:nil userInfo:@{@"key":@"我是通知传值"}];
[self dismissViewControllerAnimated:YES completion:^{
}];
}