UIpickerView

#import "DengViewController.h"

@interface DengViewController ()

@end

@implementation DengViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    CGRect rect=CGRectMake(0, 0,320, 220);
    _showlabel=[[UILabel alloc] initWithFrame:rect];
    _showlabel.backgroundColor=[UIColor grayColor];
    _showlabel.textAlignment=NSTextAlignmentCenter;
    _showlabel.font=[UIFont systemFontOfSize:18];
    [self.view addSubview:_showlabel];
    
    
    UIPickerView *pickerview = [[UIPickerView alloc] init];
    CGRect fram =pickerview.frame;
    fram.origin.y=self.view.bounds.size.height-fram.size.height;
    pickerview.frame=fram;
    pickerview.showsSelectionIndicator=YES;
    pickerview.backgroundColor=[UIColor yellowColor];
    pickerview.delegate=self;
    pickerview.dataSource=self;
    [self.view addSubview:pickerview];
    
    [pickerview reloadAllComponents];
    [self pickerView:pickerview didSelectRow:0 inComponent:0];
    
    
    // Do any additional setup after loading the view, typically from a nib.
}

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 2;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    return 9;
}

- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{
    return 30;
}

- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component{
    return 80;
}

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
    if (view==nil) {
        CGFloat width = [self pickerView:pickerView widthForComponent:component];
        CGFloat heigh = [self pickerView:pickerView rowHeightForComponent:row];
        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, width, heigh)];
        label.textAlignment=NSTextAlignmentCenter;
        label.font=[UIFont systemFontOfSize:16];
        view=label;
        
        
    }
    UILabel *label =(UILabel*)view;
    label.text=[NSString stringWithFormat:@"%d",row+1];
    if (row%2!=1) {
        label.backgroundColor=[UIColor redColor];
    }
    return label;
    
    
    
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
    NSInteger row0 =[pickerView selectedRowInComponent:0];
    NSInteger row1 =[pickerView selectedRowInComponent:1];
    UILabel *label1=(UILabel *)[pickerView viewForRow:row0 forComponent:0];
    UILabel *label2=(UILabel *)[pickerView viewForRow:row1 forComponent:1];
    int result =label1.text.intValue*label2.text.intValue;
    _showlabel.text=[NSString stringWithFormat:@"%d",result];
    
    
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end