iOS App中UIPickerView选择栏控件的使用实例解析

    NSInteger cityRow = [picker selectedRowInComponent:kCityComponent];
    
    NSString *province = [self.provinces objectAtIndex:provinceRow];
    NSString *city = [self.cities objectAtIndex:cityRow];
    
    NSString *title = [[NSString alloc] initWithFormat:@"你选择了%@.", city];
    NSString *message = [[NSString alloc] initWithFormat:@"%@属于%@", city, province];
    
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:title message:message delegate:nil cancelButtonTitle:@"好的" otherButtonTitles: nil];
    [alert show];
}
4.5 在@end之前添加代码：
复制代码
#pragma mark -
#pragma mark Picker Date Source Methods
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    return 2;
}

 

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    if (component == kProvinceComponent) {
        return [self.provinces count];
    }
    return [self.cities count];
}

#pragma mark Picker Delegate Methods
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    if (component == kProvinceComponent) {
        return [self.provinces objectAtIndex:row];
    }
    return [self.cities objectAtIndex:row];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    if (component == kProvinceComponent) {
        NSString *selectedState = [self.provinces objectAtIndex:row];
        NSArray *array = [provinceCities objectForKey:selectedState];
        self.cities = array;
        [picker selectRow:0 inComponent:kCityComponent animated:YES];
        [picker reloadComponent:kCityComponent];
    }
}

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component {
    if (component == kCityComponent) {
        return 150;