使用通知选择城市

选择当前城市，在Main.storyboard中实现如图所示：



SelectCityViewController.h中代码如下：

#import <UIKit/UIKit.h>

#define kDisplayProvince 0

#define kDisplayCity 1

#define kDisplayArea 2

@interface SelectCityViewController :
UIViewController<UITableViewDelegate,UITableViewDataSource>

@property(nonatomic,strong)UITableView *tableView;

@property(nonatomic,assign)int displayType;

@property(nonatomic,strong)NSArray *provinces;

@property(nonatomic,strong)NSArray *citys;

@property(nonatomic,strong)NSArray *areas;

@property(nonatomic,strong)NSString *selectedProvince;//选中的省

@property(nonatomic,strong)NSString *selectedCity;//选中的市

@property(nonatomic,strong)NSString *selectedArea;//选中的区

@end

SelectCityViewController.m中代码如下：

#import "SelectCityViewController.h"

#import "ViewController.h"

@interface
SelectCityViewController ()

@property(nonatomic,strong)NSIndexPath *selectedIndexPath;//当前选中的NSIndexPath

@end

@implementation SelectCityViewController

- (void)viewDidLoad {

[super
viewDidLoad];

// Do any additional setup after loading the view.

[self
configureData];

[self
configureViews];

}

-(void)configureData{

if (self.displayType
== kDisplayProvince) {

//从文件读取地址字典

NSString *addressPath = [[NSBundle
mainBundle] pathForResource:@"address"
ofType:@"plist"];

NSMutableDictionary *dict = [[NSMutableDictionary
alloc]initWithContentsOfFile:addressPath];

self.provinces = [dict
objectForKey:@"address"];

}

}

-(void)configureViews{

if (self.displayType
== kDisplayProvince) { //只在选择省份页面显示取消按钮

self.navigationItem.leftBarButtonItem
= [[UIBarButtonItem
alloc]initWithTitle:@"取消"
style:UIBarButtonItemStylePlain
target:self
action:@selector(cancel)];

}

if (self.displayType
== kDisplayArea) {//只在选择区域页面显示确定按钮

self.navigationItem.rightBarButtonItem
= [[UIBarButtonItem
alloc]initWithTitle:@"确定"
style:UIBarButtonItemStylePlain
target:self
action:@selector(submit)];

}

CGRect frame = [self.view
bounds];

self.tableView = [[UITableView
alloc]initWithFrame:frame];

self.tableView.delegate =
self;

self.tableView.dataSource =
self;

[self.view
addSubview:self.tableView];

}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{

if (self.displayType
== kDisplayProvince) {

return self.provinces.count;

}else if (self.displayType ==
kDisplayCity){

return self.citys.count;

}else{

return self.areas.count;

}

}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

static NSString* ID =
@"cityCell";

UITableViewCell *cell = [tableView
dequeueReusableCellWithIdentifier:ID];

if (!cell) {

cell = [[UITableViewCell
alloc]initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:ID];

if (self.displayType ==
kDisplayArea) {

cell.accessoryType =
UITableViewCellAccessoryNone;

}else{

cell.accessoryType =
UITableViewCellAccessoryDisclosureIndicator;

}

}

if (self.displayType
== kDisplayProvince) {

NSDictionary *province =
self.provinces[indexPath.row];

NSString *provinceName = [province
objectForKey:@"name"];

cell.textLabel.text= provinceName;

}else if (self.displayType ==
kDisplayCity){

NSDictionary *city =
self.citys[indexPath.row];

NSString *cityName = [city
objectForKey:@"name"];

cell.textLabel.text= cityName;

}else{

cell.textLabel.text=
self.areas[indexPath.row];

cell.imageView.image = [UIImage
imageNamed:@"unchecked"];

}

return cell;

}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{

if (self.displayType
== kDisplayProvince) {

NSDictionary *province =
self.provinces[indexPath.row];

NSArray *citys = [province
objectForKey:@"sub"];

self.selectedProvince = [province
objectForKey:@"name"];

//构建下一级视图控制器

SelectCityViewController *cityVC = [[SelectCityViewController
alloc]init];

cityVC.displayType =
kDisplayCity;//显示模式为城市

cityVC.citys = citys;

cityVC.selectedProvince =
self.selectedProvince;

[self.navigationController
pushViewController:cityVC animated:YES];

}else if (self.displayType ==
kDisplayCity){

NSDictionary *city =
self.citys[indexPath.row];

self.selectedCity = [city
objectForKey:@"name"];

NSArray *areas = [city
objectForKey:@"sub"];

//构建下一级视图控制器

SelectCityViewController *areaVC = [[SelectCityViewController
alloc]init];

areaVC.displayType =
kDisplayArea;//显示模式为区域

areaVC.areas = areas;

areaVC.selectedCity =
self.selectedCity;

areaVC.selectedProvince =
self.selectedProvince;

[self.navigationController
pushViewController:areaVC animated:YES];

}

else{

//取消上一次选定状态

UITableViewCell *oldCell = [tableView
cellForRowAtIndexPath:self.selectedIndexPath];

oldCell.imageView.image = [UIImage
imageNamed:@"unchecked2"];

//勾选当前选定状态

UITableViewCell *newCell = [tableView
cellForRowAtIndexPath:indexPath];

newCell.imageView.image = [UIImage
imageNamed:@"checked2"];

//保存

self.selectedArea =
self.areas[indexPath.row];

self.selectedIndexPath = indexPath;

}

}

-(void)submit{

// NSString *msg = [NSString stringWithFormat:@"%@-%@-%@",self.selectedProvince,self.selectedCity,self.selectedArea];

// UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"选择地址" message:msg delegate:nil cancelButtonTitle:@"取消" otherButtonTitles:nil,
nil];

// [alert show];

//发送通知

[[NSNotificationCenter defaultCenter] postNotificationName:@"MangoIos" object:nil userInfo:@{@"input":self.selectedArea}];

[self.navigationController popToRootViewControllerAnimated:YES];

}

-(void)cancel{

[self.navigationController
popViewControllerAnimated:YES];

}

@end

在ViewConreoller.m中代码如下：

#import "ViewController.h"

@interface
ViewController ()

@property (weak,
nonatomic) IBOutlet
UILabel *nowCityLable;

@end

@implementation ViewController

- (void)viewDidLoad {

[super
viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.

//1.注册通知

/*

通知是一对多的关系，发送一个通知，可以有多个观察者同时存在

第一个参数：添加观察者(接收通知的观察者对象一定要比发送通知的对象先创建)

第二个参数：收到通知之后要执行的方法

第三个参数：通知的名字

第四个参数：传递参数，可以是nil

*/

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(changeLable:) name:@"MangoIos" object:nil];

}

- (void)dealloc{

//3.移除通知

[[NSNotificationCenter defaultCenter] removeObserver:self];

}

- (void)changeLable:(NSNotification *)notification{

self.nowCityLable.text = notification.userInfo[@"input"];

}

- (void)didReceiveMemoryWarning {

[super
didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

@end

这样就能实现点击选择城市按钮，选择城市之后就可以把值通过通知传到当前城市。