IOS UIPickView+sqlite 选择中国所有城市案例

1.案例简介

通过读取文件，将中国所有城市写入sqlite数据库中，现通过UIPickView实现中国所有城市的选择，效果图如下所示

2.城市对象模型

中国所有城市数据请看http://blog.csdn.net/whzhaochao/article/details/37969145，城市模型对象如下

//
//  CityModel.h
//  readData
//
//  Created by 赵超 on 14-8-28.
//  Copyright (c) 2014年 赵超. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface CityModel : NSObject

@property (nonatomic,copy) NSString  *pid;      //父级城市ID
@property (nonatomic,copy) NSString  *cityName; //城市名
@property (nonatomic,copy) NSString  *ids;      //城市ID

@end

3.城市数据库操作对象

sqlite封操作BseDB类请看http://blog.csdn.net/whzhaochao/article/details/38865535，然后封装城市对象的数据库操作对象CityDB

CityDB.h文件

//
//  CityDB.h
//  readData
//
//  Created by 赵超 on 14-8-28.
//  Copyright (c) 2014年 赵超. All rights reserved.
//

#import "BaseDB.h"
#import "CityModel.h"

@interface CityDB : BaseDB
/**
 *CityDB单例
 */
+(id)ShareDB;

/**
 * 创建数据库
 * dbName:数据库名称
 */
-(void)creatTableWithDataBaseName:(NSString*) dbName;

/**
 * 增加一个城市
 * city:城市
 * dbName:数据库名称
 */
-(BOOL)addCity:(CityModel*)city dbName:(NSString*)dbName;
/**
 * 选择所有的城市
 * dbName:数据库名称
 */
-(id)selectAllCity:(NSString*)dbName;
/**
 * 选择所有的省份
 * dbName:数据库名称
 */
-(id)selectAllProvince:(NSString *)dbName;
/**
 * 删除所有城市
 * dbName:数据库名称
 */
-(BOOL)deleteAllCity:(NSString*)dbName;
/**
 * 通过上一级省份选择下级市
 * city:上一级城市
 * dbName:数据库名称
 */
-(id)selectCityByProvince:(CityModel*)provice dbName:(NSString*)dbName;


@end

CityDB.m文件实现

//
//  CityDB.m
//  readData
//
//  Created by 赵超 on 14-8-28.
//  Copyright (c) 2014年 赵超. All rights reserved.
//

#import "CityDB.h"

@implementation CityDB

static CityDB *citydb;

+(id)ShareDB{
    if (citydb==nil) {
        citydb=[[CityDB alloc] init];
    }
    return citydb;
}

-(void)creatTableWithDataBaseName:(NSString *)dbName{
     NSString *sql=@"create table china (ids text primary key,cityName text,pid text )";
    [self createTable:sql dataBaseName:dbName];
}

-(BOOL)addCity:(CityModel *)city dbName:(NSString *)dbName{
    NSString *sql=@"insert into china values (?,?,?)";
    NSArray *params=@[city.ids,city.cityName,city.pid];
    return [self execSql:sql parmas:params dataBaseName:dbName];
}

-(id)selectAllCity:(NSString *)dbName{
    NSString *sql=@"select ids,cityName,pid from china";
    return [self selectCity:sql parmas:nil dbName:dbName];
}

-(id)selectCity:(NSString*)sql parmas:(NSArray*)params dbName:(NSString*)dbName{
    NSArray *result= [self selectSql:sql parmas:params dataBaseName:dbName];
    NSMutableArray *citys=[NSMutableArray array];
    for (NSDictionary *dic in result) {
        CityModel *city=[[CityModel alloc]init];
        city.ids=[dic objectForKey:@"ids"];
        city.cityName=[dic objectForKey:@"cityName"];
        city.pid=[dic objectForKey:@"pid"];
        [citys addObject:city];
    }
    return citys;
}

-(id)selectAllProvince:(NSString *)dbName{
    NSString *sql=@"select ids,cityName,pid from china where pid=?";
    NSArray  *parmas=@[@"0"];
    return [self selectCity:sql parmas:parmas dbName:dbName];
}

-(id)selectCityByProvince:(CityModel *)provice dbName:(NSString *)dbName{
    NSString *sql=@"select * from china where pid=?";
    NSArray  *params=@[provice.ids];
    return [self selectCity:sql parmas:params dbName:dbName];
}

-(BOOL)deleteAllCity:(NSString *)dbName{
    NSString *sql=@"delete from china";
    return [self execSql:sql parmas:nil dataBaseName:dbName];
}

@end

4.城市数据处理

中国城市数据放在china.txt中，需要处理后写入数据库中，读取文件装数据写入数据库代码如下

//调用CitDB对象向数据库中增加一个城市
-(void)addCity:(CityModel* )city{
    [[CityDB ShareDB] addCity:city dbName:@"China.sqlite"];
}
//处理china.txt城市数据，将其写入数据库中
-(void)readData{
    NSString *path=[[NSBundle mainBundle] pathForResource:@"china" ofType:@"txt"];
    NSLog(@"%@",path);
    char  pid[30],name[30],ids[30];
    
    FILE *f=fopen([path UTF8String], "r");
    int i=0;
    while (!feof(f)) {
        CityModel *city=[[CityModel alloc] init];
        fscanf(f, " %s %s %s ",ids,name,pid);
        NSString *pids=[NSString stringWithUTF8String:pid];
        NSString *names=[NSString stringWithUTF8String:name];
        NSString *idss=[NSString stringWithUTF8String:ids];
        city.ids=idss;
        city.pid=pids;
        city.cityName=names;
        //向数据库插入一个城市
        [self addCity:city];
        NSLog(@"%@ %@ %@ %d",pids,names,idss,++i);
        
    }
}

5.UIPickView显示数据

MainViewControoler用户数据的显示，其.h文件内容如下

@interface MainViewController : UIViewController<UIPickerViewDataSource,UIPickerViewDelegate>{
    CityModel *privceModel;     //选择的省
    CityModel *cityModel;       //选择的市
    CityModel *subCityModel;    //选择的地级市
    CityModel *areaModel;       //选择的区
    UILabel *selectCity;        //显示选择的结果
}


@property (nonatomic,retain) NSArray *privices;    //所有省份

@property (nonatomic,retain) NSArray *citys;       //省下对应的市

@property (nonatomic,retain) NSArray *subCitys;    //市下对应的地级市

@property (nonatomic,retain) NSArray *area;        //区


@end

在MainViewController的viewDidLoad中添加UIPickView并初始化数据

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor=[UIColor grayColor];
    
    UIPickerView *pickView=[[UIPickerView alloc] initWithFrame:CGRectMake(0, 100, 0, 0)];
    pickView.dataSource=self;
    pickView.delegate=self;
    pickView.showsSelectionIndicator=YES;
    pickView.backgroundColor=[UIColor whiteColor];

    
    [self.view addSubview:pickView];
    //初始化数据
    self.privices=[[CityDB ShareDB] selectAllProvince:dataBaseName];
    CityModel *city=[self.privices objectAtIndex:0];
    self.citys=[[CityDB ShareDB] selectCityByProvince:city dbName:dataBaseName];
    city=[self.citys objectAtIndex:0];
    self.subCitys=[[CityDB ShareDB] selectCityByProvince:city dbName:dataBaseName];
    city=[self.citys objectAtIndex:0];
    self.area=[[CityDB ShareDB] selectCityByProvince:city dbName:dataBaseName];
    
    selectCity=[[UILabel alloc] initWithFrame:CGRectMake(0, 40, 320, 30)];
}

实现UIPickView的列数和行数代理函数，列数只有4列，第一列的行数是中国所有的省数所以中人返回self.privices.count就可以了，但是第二列必需知道第一列选中哪个省份后，再通过这个省份从数据库库查出下面的市才知道要显示的行数，第3列是基于第2列选中的行数，第4列是基于第3列选中的列数，实现代码如下：

//UIPcikView总共4列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 4;
}

//为每列加载行数
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    
    if (component==0) {
        return self.privices.count;
    }else
    if (component==1) {
        //获取第一列选中的省份列表
        NSInteger privoceIndex=[pickerView selectedRowInComponent:0];
        CityModel *privoice=[self.privices objectAtIndex:privoceIndex];
        //从数据库中查询，省份下面的市
        self.citys=[[CityDB ShareDB] selectCityByProvince:privoice dbName:dataBaseName];
        //返回市的个数
        return self.citys.count;
 
    }else
    if (component==2) {
        NSInteger cityIndex=[pickerView selectedRowInComponent:1];
        if (self.citys.count==0) {
            return 0;
        }
        CityModel *subCitys=[self.citys objectAtIndex:cityIndex];
        self.subCitys=[[CityDB ShareDB] selectCityByProvince:subCitys dbName:dataBaseName];
        return self.subCitys.count;
        
    }else
    if (component==3) {
        NSInteger subCityIndex=[pickerView selectedRowInComponent:2];
        if (self.subCitys.count==0) {
            return 0;
        }
        CityModel *ares=[self.subCitys objectAtIndex:subCityIndex];
        self.area=[[CityDB ShareDB] selectCityByProvince:ares dbName:dataBaseName];
        return self.area.count;
    
    }else{
        return 0;
    }
    
}

为UIPickView加载每行每列的数据，获取数据时要注意有判断是否为空

//获取每列每行的名称
-(NSString*)getCityName:(NSInteger)row componet:(NSInteger) component{
    if (component==0) {
        CityModel *city=[self.privices objectAtIndex:row];
        return city.cityName;
    }else if (component==1) {
        CityModel *city=[self.citys objectAtIndex:row];
        return city.cityName;
    }else if (component==2) {
        if (self.subCitys==nil) {
            return @"";
        }else{
            CityModel *city=[self.subCitys objectAtIndex:row];
            return city.cityName;
        }
    }
    else if (component==3) {
        if (self.area==nil) {
            return @"";
        }else{
            CityModel *city=[self.area objectAtIndex:row];
            return city.cityName;
        }
        
    }
    
    return @"";
}

-(UIView*) pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
    
    UILabel *lable=[[UILabel alloc] initWithFrame:CGRectMake(0, 0, 60, 30)];
    //获取名称
    lable.text=[self getCityName:row componet:component];
    lable.font=[UIFont systemFontOfSize:14];
    
    return lable;
}

最后实现UIPickView的选择响应事件刷新Pickview，并显示选择的结果

//获取每列每行的名称
-(NSString*)getCityName:(NSInteger)row componet:(NSInteger) component{
    if (component==0) {
        CityModel *city=[self.privices objectAtIndex:row];
        return city.cityName;
    }else if (component==1) {
        CityModel *city=[self.citys objectAtIndex:row];
        return city.cityName;
    }else if (component==2) {
        if (self.subCitys==nil) {
            return @"";
        }else{
            CityModel *city=[self.subCitys objectAtIndex:row];
            return city.cityName;
        }
    }
    else if (component==3) {
        if (self.area==nil) {
            return @"";
        }else{
            CityModel *city=[self.area objectAtIndex:row];
            return city.cityName;
        }
        
    }
    
    return @"";
}

-(UIView*) pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
    
    UILabel *lable=[[UILabel alloc] initWithFrame:CGRectMake(0, 0, 60, 30)];
    //获取名称
    lable.text=[self getCityName:row componet:component];
    lable.font=[UIFont systemFontOfSize:14];
    
    return lable;
}

项目完整工程https://github.com/whzhaochao/IOSChinaCity