UIPickView的使用

//初始化：
    TimesPickerView = [[UIPickerView alloc] initWithFrame:CGRectZero];
    CGRect pickerRect = CGRectMake(w, h, x, y);
    TimesPickerView.frame = pickerRect;
    TimesPickerView.showsSelectionIndicator = YES;    
    [TimesPickerView setBackgroundColor:[UIColor clearColor]];
    TimesPickerView.autoresizingMask = UIViewAutoresizingFlexibleWidth;
    TimesPickerView.delegate=self;  //设置委托
    [self.view  addSubview:TimesPickerView]; 
 
Picker View需要两个接口：DataSource和Delegate。
在定义接口的地方要有如下定义:

一个类必须至少实现下列方法：

@interface SingleComponentPickerViewController : UIViewController
<UIPickerViewDelegate, UIPickerViewDataSource>

#pragma mark -
#pragma mark Picker Data Source Methods

- (NSInteger) numberOfComponentsInPickerView: (UIPickerView *) pickerView
{
    return 1;
}

- (NSInteger) pickerView: (UIPickerView *)pickerView
numberOfRowsInComponent: (NSInteger) component
{
    return [pickerData count];
}

#pragma mark Picker Delegate Methods
- (NSString *) pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger) row
             forComponent:(NSInteger) component{
    return [pickerData objectAtIndex:row];
}

其中Data Source提供了数据，而Delegate则实际获取数据。

如果要接收某个Component被选择的消息，则要实现一个delegate方法:

- (void) pickerView:(UIPickerView *) pickerView
didSelectRow: (NSInteger) row
        inComponent: (NSInteger) component{
    if (component == kStateComponent) {
        NSString *selectedState = [self.states objectAtIndex:row];
        NSArray *array = [stateZips objectForKey:selectedState];
        self.zips = array;
        [picker selectRow:0 inComponent: kZipComponent animated:YES];
        [picker reloadComponent:kZipComponent];
    }
}

 
//触发事件
- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    [pickerViewsarray objectAtIndex:row];
    switch (row) {
        case 0:
            NSLog(@"row:%d",row);
            break;
        case 1:
            NSLog(@"row:%d",row);
            break;    
}