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~~~