UIPickerView *pickView = [[UIPickerView alloc]init];
    /*协议·
     * UIPickerViewDelegate
     * UIPickerViewDataSource
     */
    pickView.delegate = self;
    pickView.dataSource = self;

pragma mark - pickView-->dataSource & delegate

/*/*pickView返回的列数
 *参数表示遵循代理协议的pickView
 */
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 3;
}

/*表示每一列有多少行
 *参数1:表示遵循协议代理的pickView
 *参数2:表示列数
 */
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    return 10;
}

//每一行的内容
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    return @"";
}

//设置每一行的高度
-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component{
    return 7;
}

//设置每一列中行的高度，实际都显示最高列的高度
-(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{
    return (component+1)*30;
}

//监控选中的行数和列数
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
    
}

-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
    UILabel *label = [[UILabel alloc]init];
   
    return label;
}

</code>