iOS简单的传值
1.协议传值
从twoViewController传到viewController
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twoViewController.h #import//声明一个协议 @protocol twoViewControllerDelegate //自定义方法来反向传值 - (void)changeWithString:(NSString *)string; @end @interface twoViewController : UIViewController @property (nonatomic, strong) UITextField *firstTextField; @property (nonatomic, strong) UITextField *secondTextField; @property (nonatomic, strong) UIButton *button; //定义属性delegate 用weak修饰防止循环引用 @property (nonatomic, weak) id delegate; @end twoViewController.m #import "twoViewController.h" @interface twoViewController () @end @implementation twoViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. self.view.backgroundColor = [UIColor yellowColor]; self.firstTextField = [[UITextField alloc] initWithFrame:CGRectMake(10, 100, 200, 50)]; _firstTextField.backgroundColor = [UIColor whiteColor]; _firstTextField.layer.masksToBounds = YES; _firstTextField.layer.cornerRadius = 7; [self.view addSubview:_firstTextField]; self.secondTextField = [[UITextField alloc] initWithFrame:CGRectMake(10, 200, 200, 50)]; _secondTextField.layer.masksToBounds = YES; _secondTextField.backgroundColor = [UIColor whiteColor]; _secondTextField.layer.cornerRadius = 7; [self.view addSubview:_secondTextField]; self.button = [[UIButton alloc] initWithFrame:CGRectMake(50, 270, 100, 50)]; self.button.backgroundColor = [UIColor blueColor]; [self.button setTitle:@"点击" forState:UIControlStateNormal]; [self.button addTarget:self action:@selector(clickButton:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:_button]; } - (void)clickButton:(UIButton *)sender { [self.navigationController popViewControllerAnimated:YES]; //先判断协议方法是否已经响应 if ([_delegate respondsToSelector:@selector(changeWithString:)]) { //代理传值 [_delegate changeWithString:self.firstTextField.text]; } } ViewController.h #import@interface ViewController : UIViewController @property (nonatomic, strong)UITextField *textField; @property (nonatomic, strong)UIButton *button; @end ViewController.m #import "ViewController.h" #import "twoViewController.h" @interface ViewController () @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. self.view.backgroundColor = [UIColor yellowColor]; self.textField = [[UITextField alloc] initWithFrame:CGRectMake(10, 100, 200, 50)]; self.textField.backgroundColor = [UIColor whiteColor]; self.textField.layer.masksToBounds = YES; self.textField.layer.cornerRadius = 7; [self.view addSubview:_textField]; self.button = [[UIButton alloc] initWithFrame:CGRectMake(40, 160, 100, 50)]; [_button setTitle:@"点击" forState:UIControlStateNormal]; self.button.backgroundColor = [UIColor greenColor]; [_button addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchDown]; [self.view addSubview:_button]; } - (void)click:(UIButton *)sender { twoViewController *aController = [[twoViewController alloc] init]; //遵守协议 aController.delegate = self; [self.navigationController pushViewController:aController animated:YES]; } //实现协议中的方法 - (void)changeWithString:(NSString *)string { self.textField.text = string; } 后面代码中不再有控件的实现，只是传值的重点
2.属性传值
从ViewController传到twoViewController
//在twoViewController.h中声明一个属性
@property (nonatomic, copy)NSString *string;
//在twoViewController.m 中你要传值的地方
self.firstTextField.text = self.string;
//在ViewController.m中点击button跳转函数中
- (void)click:(UIButton *)sender {
twoViewController *aController = [[twoViewController alloc] init];
//把textField.text 传给跳转页面的一个属性
aController.string = self.textField.text;
[self.navigationController pushViewController:aController animated:YES]
}3.通知传值
从twoViewController传到ViewController
//在twoViewController.m中点击button时
- (void)clickButton:(UIButton *)sender {
NSDictionary *dict = @{@"text":self.firstTextField.text};
//发送通知 userInfo 为附加属性 为字典类型
//因为有时候要传递的参数不是一个，在接受者中根据字典里面的键来取出里面的值
[[NSNotificationCenter defaultCenter] postNotificationName:@"pass" object:nil userInfo:dict];
[self.navigationController popViewControllerAnimated:YES];
}
//在ViewController.m中
//viewDidLoad中注册监听者，name要和发送通知页面（twoViewController）的name相同，用来区分时哪一个通知，object 的值为nil时，代表监听任何对象发送的通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(pass:) name:@"pass" object:nil];
在接受者中实现通知中的方法
- (void)pass:(NSNotification *)text {
//如果时传递多个数据，将对应中数据取出来即可
self.textField.text = text.userInfo[@"text"];
}4.block传值
从twoViewController传到ViewController
twoViewController.h
#import
//重新定义一个名字
typedef void (^ReturnTextBlock)(NSString *showText);
@interface twoViewController : UIViewController
@property (nonatomic, strong) UITextField *firstTextField;
@property (nonatomic, strong) UITextField *secondTextField;
@property (nonatomic, strong) UIButton *button;
//定义一个block属性
@property (nonatomic,copy) ReturnTextBlock returnTextBlock;
- (void)returnText:(ReturnTextBlock)block;
@end
twoViewController.m
//把传进来的Block语句块保存到本类的实例变量returnTextBlock中
-(void)returnText:(ReturnTextBlock)block{
self.returnTextBlock = block;
}
//当视图即将消失时 重写
-(void)viewWillDisappear:(BOOL)animated{
if (self.returnTextBlock != nil) {
self.returnTextBlock(self.firstTextField.text);
}
}
ViewController.m
- (void)click:(UIButton *)sender {
twoViewController *aController = [[twoViewController alloc] init];
//回掉方法将输入框中的数据传给textField
[aController returnText:^(NSString *showText) {
self.textField.text = showText;
}];
[self.navigationController pushViewController:aController animated:YES];
}