29.导航控制器和页面间的传值

1.基本概念

1. 导航控制器可以认为是管理控制器的控制器,主要管理有层级关系的控制器,任何继承⾃自UIViewController的类(多态)都可以作为根控制器,viewControllers属性存储了栈中的所有被管理的控制器。
2. UINavigationController继承于UIViewController,以栈的方式管理所控制的视图控制器,至少要有一个被管理的视图控制器,这个控制器我们称作导航控制器的根视图控制器。
3. UINavigationController通过栈的方式管理控制器的切换,控制入栈和出栈来展⽰示各个视图控制器。UINavigationController的ContentView里始终显示栈顶控制器的view。
4. navigationBar—导航条,iOS7之后默认是半透明的,iOS7之前默认是不透明的。navigationBar在透明情况,与contentView会重合一部分区域。navigationBar在不透明情况,contentView紧跟在navigationBar的下面,所以我们通常通过属性translucent把它设置为不透明的。navigationBar竖屏下默认高度44,横屏下默认高度32.
5. UINavigationBar除了能定义⾃身的样式外,还管理一组UINavigationItem。与UINavigationController相似,UINavigationBar也是以栈的方式管理一组UINavigationItem。提供push和pop操作item。
6. barTintColor设置导航条的颜色 setBackgroundImage:forBarMetrics:导航条加背景图片.navigationController属性,父类中的属性,每个在栈中的控制器,都能通过此属性,获取自己所在的UINavigationController对象。
7. UINavigationController以栈的方式管理视图控制器。通过push和pop控制跳转,每个视图控制器都有一个navigationItem属性。navigationItem中设置的左按钮、右按钮、标题等,会随着控制器的显示,也显示到navigationBar上.
8. UINavigationBar管理一组UINavigationItem,UINavigationItem包含了UIBarButtonItem。
9. 使⽤用属性传值解决从前往后传值的问题, 使⽤用delegate解决从后往前传值的问题

2.MainVIewController文件

#import <UIKit/UIKit.h>
@interface MainViewController : UIViewController
@property(nonatomic,retain)UITextField *mainTxtField;
@end

#import "MainViewController.h"
#import "SecondViewController.h"

//4.签订协议
@interface MainViewController ()<SecondViewControllerDelegate>
@property(nonatomic,retain)UILabel *label;
@property(nonatomic,retain)UIButton *button;
@end
@implementation MainViewController

- (void)dealloc
{
    [_button release];
    [_label release];
    [_mainTxtField release];
    [super dealloc];
}
- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor greenColor];
    self.navigationController.navigationBar.translucent = NO;

    ////第一种方式设置标题
    self.title = @"猫眼电影";
    //背景颜色的设置(不是所有的背景颜色都是backgroundColor)
    self.navigationController.navigationBar.barTintColor = [UIColor whiteColor];
    //为了防止坐标系被篡改,我们把bar从半透明设置成不透明,这样坐标系的原点就贵自动向下推64
    self.navigationController.navigationBar.translucent = NO;

    //第二种方式设置标题
    self.navigationItem.title = @"逗比青年";
    UISegmentedControl *seg = [[UISegmentedControl alloc] initWithItems:@[@"信息",@"通话"]];
    //指定一些视图,称为titleView
    self.navigationItem.titleView = seg;
    //创建左右两边的按钮(下面这个是系统提供的BarButtonItem),添加系统提供的或者自定义的BarButtonItem到导航栏上默认的显示颜色都为蓝色
    self.navigationItem.leftBarButtonItem = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemBookmarks target:self action:@selector(letfButtonAcrion:)]autorelease];

    //下面这个给方法rightBarButtonItem设置一个黑色的"充"的图片,添加上去系统会把它变为蓝色
    //self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"iconfont-chongzhi.png"] style:UIBarButtonItemStylePlain target:self action:@selector(rightclick:)]autorelease];
    //下面这个给方法rightBarButtonItem设置一个黑色的"充"的图片,添加上去还是黑色
    UIButton *buttton1 = [UIButton buttonWithType:UIButtonTypeCustom];
    buttton1.frame = CGRectMake(0, 0, 40, 40);
    [buttton1 setImage:[UIImage imageNamed:@"iconfont-chongzhi.png"] forState:UIControlStateNormal];
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:buttton1];

    self.label = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 140, 40)];
    self.label.backgroundColor = [UIColor redColor];
    [self.view addSubview:self.label];
    [_label release];

    self.mainTxtField = [[UITextField alloc] initWithFrame:CGRectMake(100, 180, 140, 40)];
    self.mainTxtField.borderStyle = UITextBorderStyleRoundedRect;
    self.mainTxtField.placeholder = @"请输入传值内容";
    [self.view addSubview:self.mainTxtField];
    [_mainTxtField release];

    self.button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    self.button.frame = CGRectMake(100, 250, 140, 40);
    [self.view addSubview:self.button];
    self.button.layer.borderWidth = 0.4;
    self.button.layer.cornerRadius = 10;
    [self.button setTitle:@"下一页" forState:UIControlStateNormal];
    [self.button addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
}

- (void)letfButtonAcrion:(UIBarButtonItem *)button{
}

- (void)rightclick:(UIBarButtonItem *)button{
}

- (void)click:(UIButton *)button{
    SecondViewController *secondVC = [[SecondViewController alloc] init];
    //模态跳转页面
    //[secondVC setModalPresentationStyle:UIModalPresentationPageSheet];
    //[self presentViewController:secondVC animated:YES completion:^{
    //}];
    [self.navigationController pushViewController:secondVC animated:YES];
    //通过属性向后面页面传值
    secondVC.number = 100;
    secondVC.str = self.mainTxtField.text;
    secondVC.array = @[@"1",@"2"];
    //后面页面值通过协议传回来
    //5.设置代理人
    secondVC.delegate = self;
    [secondVC release];
}
//6.实现协议方法
- (void)changeValue:(NSString *)value{
    self.label.text = value;
}

3.SecondViewController文件

#import <UIKit/UIKit.h>
//协议传值的第一步
//1.声明一份协议
@protocol SecondViewControllerDelegate <NSObject>
//协议方法
- (void)changeValue:(NSString *)value;
@end

@interface SecondViewController : UIViewController
//属性传值第一步,在第二个页面写一条属性
@property(nonatomic,assign)NSInteger number;
//针对字符串写一条属相
@property(nonatomic,copy)NSString *str;
@property(nonatomic,retain)NSArray *array;

//2.设置代理人的属性
@property(nonatomic,assign)id<SecondViewControllerDelegate> delegate;
@end

#import "SecondViewController.h"
@interface SecondViewController ()
@property(nonatomic,retain)UITextField *textField;
@property(nonatomic,retain)UIButton *button;
@property(nonatomic,strong)UILabel *label;
@end
@implementation SecondViewController
- (void)dealloc
{
    [_textField release];
    [_button release];
    [_label release];
    [_array release];
    [_str release];
    [super dealloc];
}

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor redColor];
    self.title = @"第二页";

    self.label = [[UILabel alloc] initWithFrame:CGRectMake(100, 100, 140, 40)];
    self.label.backgroundColor = [UIColor blueColor];
    [self.view addSubview:self.label];
    //把从MainViewController传过来的值显示在label里,即把属性里的值赋值给label
    self.label.text = self.str;
    [_label release];

    self.textField = [[UITextField alloc] initWithFrame:CGRectMake(100, 180, 140, 40)];
    self.textField.borderStyle = UITextBorderStyleRoundedRect;
    self.textField.placeholder = @"请输入返回内容";
    [self.view addSubview:self.textField];
    [_textField release];

    self.button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    self.button.frame = CGRectMake(100, 250, 140, 40);
    [self.view addSubview:self.button];
    self.button.layer.borderWidth = 0.4;
    self.button.layer.cornerRadius = 10;
    [self.button setTitle:@"返回" forState:UIControlStateNormal];
    [self.button addTarget:self action:@selector(click:) forControlEvents:UIControlEventTouchUpInside];
    //打印从MainViewController传过来的值
    NSLog(@"%ld",self.number);
    NSLog(@"%@",self.array);
}

- (void)click:(UIButton *)button{
    [self.navigationController popToRootViewControllerAnimated:YES];
    //协议的触发条件是点击按钮
    //3.设置代理人执行的协议方法
    [self.delegate changeValue:self.textField.text];
}

4.简单的效果图如下