iOS開發日記48-詳解UIPickerView，48-uipickerview

iOS開發日記48-詳解UIPickerView，48-uipickerview

今天博主有一個UIPickerView的需求,遇到了一些困痛點,在此和大家分享,希望能夠共同進步.

UIPickerView是一個選取器控制項，它比UIDatePicker更加通用，它可以產生單列的選取器，也可產生多列的選取器，而且開發人員完全可以自訂選擇項的外觀，因此用法非常靈活.

UIPickerView直接繼承了UIView，沒有繼承UIControl，因此，它不能像UIControl那樣綁定事件處理方法，UIPickerView的事件處理由其委派物件完成.

    self.viewOfPick=[[UIPickerView alloc]initWithFrame:CGRectMake(100, 0, 200, [UIScreen mainScreen].bounds.size.height)];

    _viewOfPick.dataSource=self;

    _viewOfPick.delegate=self;

//pickerView預設選中row為0,無線滾動只是在一開始的時候顯示row的中間值,造成無線滾動的假象

    [_viewOfPick selectRow:9 inComponent:0 animated:YES];

//設定pickerView預設選中最後一行

    [_viewOfPick selectRow:9 inComponent:1 animated:YES];

    [self.view addSubview:_viewOfPick];

//類似tableView的cell for row,根據row和component返回字串顯示

- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component __TVOS_PROHIBITED

{

    return @"空";

}

//類似tableView的didSelect,根據row和component進行具體的傳值等操作

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component __TVOS_PROHIBITED

{

    NSLog(@"*********%ld,%ld",(long)component,row);

}

//類似tableView的cell for row,根據row和component返回自訂視圖顯示

//注意,同時實現返回NSString 和下面這個 返回UIView的方法,只執行返回UIView的方法

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view __TVOS_PROHIBITED

{

    UIView *blackView=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 10, 10)];

    blackView.backgroundColor=[UIColor blackColor];

    return blackView;

}

//返回pickerView的行高

- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component __TVOS_PROHIBITED

{

    return 40;

}

// returns the number of 'columns' to display.component的數量

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

{

    return 2;

}

 

// returns the # of rows in each component..row的數量

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component

{

    return 10;

}