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iOS块传值

發布時間：2023/12/15 编程问答 27 豆豆

生活随笔收集整理的這篇文章主要介紹了 iOS块传值小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

塊傳值，塊類似于C中的函數指針。在Controller中傳遞數據非常方便，還是繼續上一章的例子，將數據從Second傳遞到First，這里使用塊來完成,看起來似乎和協議很像，不過比協議略簡單。

代碼如下所示：

///

FirstViewController

- (void)viewDidLoad

{

????[super viewDidLoad];

????

????self.nameLable = [[[UILabel alloc]initWithFrame:CGRectMake(10, 10, 300, 60)]autorelease];

????self.nameLable.textAlignment = UITextAlignmentCenter;

????self.nameLable.font = [UIFont systemFontOfSize:50];

????self.nameLable.textColor = [UIColor blueColor];

????[self.view addSubview:self.nameLable];

????

????UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];

????button.frame = CGRectMake(130, 170, 60, 40);

????[button setTitle:@"下一個" forState:UIControlStateNormal];

????[button addTarget:self action:@selector(pushNext:) forControlEvents:UIControlEventTouchUpInside];

????[self.view addSubview:button];

}

- (void)pushNext:(id)sender

{

????//初始化second

????SecondViewController *second = [[SecondViewController alloc]init];

????///調用塊

????second.send = ^(NSString *str){

????????self.nameLable.text = str;

????};

????//推過去

????[self.navigationController pushViewController:second animated:YES];

????[second release];

}

Objective-C

SecondViewController.h

#import <UIKit/UIKit.h>

typedef??void (^SendMessage) (NSString *str); ///聲明塊

@interface SecondViewController : UIViewController<UITextFieldDelegate>

@property (nonatomic, copy) SendMessage send;??//聲明一個塊類型屬性

@end

/SecondViewController.m

- (void)viewDidLoad

{

????[super viewDidLoad];

????

????UITextField *textFd = [[UITextField alloc]initWithFrame:CGRectMake(10, 10, 300, 150)];

????textFd.borderStyle = UITextBorderStyleRoundedRect;

????textFd.delegate = self;

????textFd.tag = 100;

????[self.view addSubview:textFd];

????[textFd release];

}

- (BOOL)textFieldShouldReturn:(UITextField *)textField

{

????[textField resignFirstResponder];

????//先判斷，在調用塊傳遞實參

????if (self.send) {

????????self.send (textField.text);

????}

????return YES;

}

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