iOS基础控件UINavigationController中的传值

#import <UIKit/UIKit.h>//声明一个协议@PRotocol SendValue<NSObject>//定义一个方法- (void)sendBtnTitle:(NSString *)title;@end@interface FirstViewController : UIViewController// 定义代理@property (nonatomic, assign) id <SendValue>delegate;// 创建一个正向传值的属性@property (nonatomic,copy) NSString *currentTitle;@end

- (void)didButton{    NSArray *btntitles = [NSArray arrayWithObjects:@"按键一",@"按键二",@"按键三", nil];        for (int i=0; i<btntitles.count; i++) {        UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];        //改变按键字体颜色        [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];        [btn setTitle:[btntitles objectAtIndex:i] forState:UIControlStateNormal];
        // 如果按钮的标题和属性中的 _currentTitle 相同，即和根页面中的导航条的 title 一样         if([_currentTitle isEqualToString:btn.currentTitle]){
            //开启选中状态            btn.selected = YES;            btn.tintColor = [UIColor whiteColor];        }        [btn setTitleColor:[UIColor redColor] forState:UIControlStateSelected];        [btn addTarget:self action:@selector(titlebtnClicked:) forControlEvents:UIControlEventTouchUpInside];        btn.frame = CGRectMake(80, 140+60*i, self.view.frame.size.width-160, 40);        btn.backgroundColor = [UIColor whiteColor];        [self.view addSubview:btn];    }}- (void)titlebtnClicked:(UIButton *)btn{            NSString *title = btn.currentTitle;

    // 判断代理中是否有 sendBtnTitle ：这个函数

    if ([_delegate respondsToSelector:@selector(sendBtnTitle:)]){

        // 代理 执行自己的 sendBtnTitle 函数，传参是 title

       [_delegate sendBtnTitle:title];

    }

    NSLog(@"%@",title);    [self.navigationController popViewControllerAnimated:YES];    }

#import <UIKit/UIKit.h>#define C(a,b,c,d) [UIColor colorWithRed:a/255.0 green:b/255.0 blue:c/255.0 alpha:d/255.0]#define IMG(name) [UIImage imageNamed:name]#import "FirstViewController.h"//将协议挂过来@interface rootViewController : UIViewController<SendValue>@end

- (void)btnClicked{    FirstViewController *first = [[FirstViewController alloc] init];    //将当前页面的navigationItem.title传递进去    //正向传值    first.currentTitle = self.navigationItem.title;    //将代理指定为当前rootViewController类的指针    first.delegate = self;    [self.navigationController pushViewController:first animated:YES];}//实现协议定义的方法- (void)sendBtnTitle:(NSString *)title{    self.navigationItem.title = title;}