UIKit框架-高级控件:9.UIPickerView简易城市地区选择器

在前面我们知道了UIPickerView的使用方法, 也结合过其他UI控件一起来使用, 现在让再来一个演练.

1.在.h文件中设置代理方法

@interface ViewController : UIViewController <UIPickerViewDataSource, UIPickerViewDelegate>

@end

2.在.m文件里设置全局变量

@interface ViewController ()
{
NSArray *_province;
NSMutableDictionary *_city;
}

PS: 这里设置全局变量是为了方便我们存储数据, 非必要时不要乱定义.

3.实例化UIPickerView

- (void)myPickerView
{
UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height - 200, self.view.frame.size.width, 268)];

[pickerView setBackgroundColor:[UIColor grayColor]];

[pickerView setDataSource:self];
[pickerView setDelegate:self];

[pickerView setShowsSelectionIndicator:YES];

[self loadPickerData];
[self.view addSubview:pickerView];
}

4.设置城市省份数据

- (void)loadPickerData
{
_province = @[@"北京", @"广西", @"广东"];
_city = [NSMutableDictionary dictionary];

NSArray *city1 = @[@"朝阳区", @"东城区", @"西城区"];
[_city setValue:city1 forKey:@"北京"];

NSArray *city2 = @[@"桂林市", @"南宁市"];
[_city setValue:city2 forKey:@"广西"];

NSArray *city3 = @[@"惠州市", @"广州市", @"深圳市", @"东莞市"];
[_city setValue:city3 forKey:@"广东"];
}

5.设置UIPickerView的数据源方法

#pragma mark 设置列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}

#pragma mark 设置行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (component == 0)
{
return _province.count;
} else {
NSInteger rowProvince = [pickerView selectedRowInComponent:0];
NSString *provinceName = _province[rowProvince];
NSArray *citys = _city[provinceName];
return citys.count;
}
}

6.设置UIPickerView的代理方法

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if (component == 0) {
return _province[row];
} else {
NSInteger rowProvince = [pickerView selectedRowInComponent:0];
NSString *provinceName = _province[rowProvince];
NSArray *citys = _city[provinceName];
return citys[row];
}
}

7.UIPickerView刷新数据的方法

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
[pickerView reloadComponent:1];

NSInteger rowOne = [pickerView selectedRowInComponent:0];
NSInteger rowTow = [pickerView selectedRowInComponent:1];

NSString *provinceName = _province[rowOne];

NSArray *citys = _city[provinceName];

NSLog(@"%@~%@", _province[rowOne], citys[rowTow]);
}

PS: 如果不添加该方法, 那么在切换省份的时候就不会更改市区.

最终效果图:


 


好了, 这次我们就讲到这里, 下次我们继续~~~