Using Uipickview to realize the linkage between provinces and cities

#import <UIKit/UIKit.h>

@interface viewcontroller:uiviewcontroller<uipickerviewdatasource,uipickerviewdelegate>

@property (strong,nonatomic) Uipickerview *pickview;

Define a mutable array to hold the data in the province

@property (strong,nonatomic) Nsmutablearray *statearry;

Defines a variable array for storing the data in the city

@property (strong,nonatomic) Nsmutablearray *citiesarry;

Define a collection of data for each province and city

@property (strong,nonatomic) Nsarray *arry;

@end

#import "ViewController.h"

@interface Viewcontroller ()

@end

@implementation Viewcontroller

-(void) Viewdidload {

[Super Viewdidload];

Get Data

NSString *path=[[nsbundle Mainbundle] pathforresource:@ "City" oftype:@ "plist"];

Initializing an array of provinces and cities

Self. Statearry=[nsmutablearray array];

Self. Citiesarry=[nsmutablearray array];

Ayyr this large array to store all the provinces and cities

Self.arry=[nsarray Arraywithcontentsoffile:path];

Get the provinces, and put the data in the province's variable set Statearry

For (Nsdictionary *arr in Self.arry)

{

[Self. Statearry addobject:arr[@ "state"];

}

Create Pickview

Self.pickview=[[uipickerview Alloc] Initwithframe:cgrectmake (0, 200, 414, 200)];

Self.pickview.backgroundcolor=[uicolor Graycolor];

self.pickview.delegate=self;

self.pickview.datasource=self;

[Self.view AddSubview:self.pickView];

}

#pragma mark data source Method Numberofcomponentsinpickerview

-(Nsinteger) Numberofcomponentsinpickerview: (Uipickerview *) Pickerview

{

Two columns

return 2;

}

#pragma mark data source Method pickerviewofrows

-(Nsinteger) Pickerview: (Uipickerview *) Pickerview numberofrowsincomponent: (Nsinteger) component

{

if (component==0)

{

Number of Provinces

return self. Statearry.count;

}

Else

{

Number of cities

return self. Citiesarry.count;

}

}

#pragma mark delegate how to display information

-(NSString *) Pickerview: (Uipickerview *) Pickerview Titleforrow: (nsinteger) Row forcomponent: (Nsinteger) component

{

if (component==0)

{

Selected provinces

return self. Statearry[row];

}

Else

{

City of Choice

return self. Citiesarry[row];

}

}

#pragma Mark selects a line of information

-(void) Pickerview: (Uipickerview *) Pickerview Didselectrow: (nsinteger) Row incomponent: (Nsinteger) component

{

if (component==0)

{

Clear the data from the last City column.

[Self. Citiesarry Removeallobjects];

Define an index to find out the corresponding subscript for all the provinces in the first scroll bar and assign the value to index

Nsinteger Index=[pickerview selectedrowincomponent:0];

Traverse out all the city

For (Nsdictionary *city in self.arry[index][@ "Cities"])

{

Append the walk-out city to the collection in the storage city

[Self. Citiesarry addobject:city[@ "City"];

}

NSLog (@ "%@", self. Citiesarry);

Update the data for the second wheel

[Self.pickview reloadcomponent:1];

}

Else

{

Show the provinces and municipalities taken out

NSString *message=[nsstring stringwithformat:@ "You chose%@ 's%@?", self. Statearry[[pickerview selectedrowincomponent:0]],self. Citiesarry[row]];

Set the caption of a popup box

Uialertcontroller *alert=[uialertcontroller alertcontrollerwithtitle:@ "hint" message:message PreferredStyle: Uialertcontrollerstylealert];

Set button name

Uialertaction *okaction=[uialertaction actionwithtitle:@ "OK" Style:uialertactionstyledefault handler:^ ( Uialertaction *action) {

}];

Set button name

Uialertaction *cancelaction=[uialertaction actionwithtitle:@ "Cancel" Style:uialertactionstylecancel Handler:nil];

Add a button to the Hint box

[Alert addaction:okaction];

[Alert addaction:cancelaction];

//

[Self Presentviewcontroller:alert animated:yes completion:nil];

}

}

-(void) didreceivememorywarning {

[Super didreceivememorywarning];

Dispose of any resources the can be recreated.

}

@end

Using Uipickview to realize the linkage between provinces and cities