IOS传值之Block传值（二）
@interface QWViewController : UIViewController
@property(nonatomic,strong)UILabel *label;
@property(nonatomic,strong)UITextField *textField;
@end
#import "QWViewController.h"
#import "QWViewControllerTwo.h"
@interface QWViewController ()
@end
@implementation QWViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
UILabel *label=[[UILabel alloc]initWithFrame:CGRectMake(100, 100, 100, 50)];
label.backgroundColor=[UIColor blueColor];
self.label=label;
[self.view addSubview:label];
UITextField *textField=[[UITextField alloc]initWithFrame:CGRectMake(100, 200, 100, 50)];
textField.backgroundColor=[UIColor yellowColor];
self.textField=textField;
[self.view addSubview:textField];
UIButton *button=[UIButton buttonWithType:UIButtonTypeCustom];
button.frame=CGRectMake(100, 300, 100, 50);
button.backgroundColor=[UIColor blackColor];
[button setTitle:@"jump" forState:UIControlStateNormal];
[button addTarget:self action:@selector(doClicked) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:button];
}
-(void)doClicked{
QWViewControllerTwo *ViewControllerTwo=[[QWViewControllerTwo alloc]init];
ViewControllerTwo.labelText=self.textField.text;//顺传值
//[ViewControllerTwo.label setText:self.textField.text];//注意：这样传值是不对的。
//逆向传值回来
[ViewControllerTwo returnText:^(NSString *showText) {
self.label.text=showText;
}];
[self.navigationController pushViewController:ViewControllerTwo animated:YES];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
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#import <UIKit/UIKit.h>
typedef void(^ReturnTextBlock) (NSString *showText);
@interface QWViewControllerTwo : UIViewController
@property(nonatomic,copy)NSString *labelText;
@property(nonatomic,strong)UILabel *label;
@property(nonatomic,strong)UITextField *textField;
@property(nonatomic,copy)ReturnTextBlock returnTextBlock;
-(void)returnText:(ReturnTextBlock)block;
@end
#import "QWViewControllerTwo.h"
@interface QWViewControllerTwo ()
@end
@implementation QWViewControllerTwo
-(UILabel *)label{
if (_label==nil) {
_label=[[UILabel alloc]initWithFrame:CGRectMake(100, 100, 100, 50)];
}
return _label;
}
-(UITextField *)textField{
if (_textField==nil) {
_textField=[[UITextField alloc]initWithFrame:CGRectMake(100, 200, 100, 50)];
}
return _textField;
}
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
UILabel *label=[[UILabel alloc]initWithFrame:CGRectMake(100, 100, 100, 50)];
label.backgroundColor=[UIColor yellowColor];
label.text=self.labelText;
self.label=label;
[self.view addSubview:self.label];
UITextField *textField=[[UITextField alloc]initWithFrame:CGRectMake(100, 200, 100, 50)];
textField.backgroundColor=[UIColor yellowColor];
self.textField=textField;
[self.view addSubview:textField];
//创建返回按钮
UIButton *backBtn=[UIButton buttonWithType:UIButtonTypeCustom];
[backBtn addTarget:self action:@selector(goBack) forControlEvents:UIControlEventTouchUpInside];
[backBtn setTitle:@"back" forState:UIControlStateNormal];
}
-(void)goBack{
[self.navigationController popViewControllerAnimated:YES];
}
//将上一个控制器传过来的block保存在本控制器中，在合适的时候调用
-(void)returnText:(ReturnTextBlock)block{
self.returnTextBlock=block;
}
//在视图将要消失的时候调用本类的block
-(void)viewWillDisappear:(BOOL)animated{
if (self.returnTextBlock !=nil) {
self.returnTextBlock(self.textField.text);//实现是在之前控制器中
}
}
@end
实现效果：
