UIPickerView 滾動選擇器

/////別忘記 .h 中寫代理  <UIPickerViewDelegate,UIPickerViewDataSource>

/////UIPickerView和UIDatePicker是類似的控件，只不過UIDatePicker是日期控件，只能放日期，而UIPickerView可以放任何東西。

(void)viewDidLoad
{
  [super viewDidLoad];
  _dataArray = [[NSArray alloc] initWithObjects:@"a", @"b", @"c", @"d", @"e", @"f", nil];
UIPickerView* pv = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 460-216, 320, 216)];
  pv.delegate = self;
  pv.dataSource = self;
  pv.showsSelectionIndicator = YES;
  [self.view addSubview:pv];
  //[pv release];
}


//多少組

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

//每一組多少行

(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
  if (component == 1) {
  return 3;

  }
  if (component == 0) {
  return _dataArray.count;

  }
  return 10;
}

//顯示每一行的文本

(NSString )pickerView:(UIPickerView )pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
  if (component == 0) {

  return [_dataArray objectAtIndex:row];

}
  return [NSString stringWithFormat:@"%d",row];
}

(UIView )pickerView:(UIPickerView )pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
  //如果是第0組
  if (component == 0) {

  //如果是第0組的第0行
  if (row == 0) {
      //return 顯示的view
  }
  if (row == 1) {
      //
  }

}
  UIView* myview = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];
  myview.backgroundColor = [UIColor redColor];
  return myview;
}


//選擇一行就會調用這個方法

(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
  NSLog(@"選擇的是第%d組，第%d行",component,row);
}</pre>