UIPickView 选择框

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属性

• 创建

UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 100, 320, 216)];

• showsSelectionIndicator————该属性控制是否显示UIPickerView中的选中标记（以高亮背景作为选中标记）

pickerView.showsSelectionIndicator = YES;

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方法

• numberOfComponents————获取UIPickerView指定列中包含的列表项的数量。该属性是一个只读属性

-(NSInteger)numberOfRowsInComponent:(NSInteger)component;

• numberOfRowsInComponent————获取UIPickerView包含的列数量

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;

• rowSizeForComponent————获取UIPickerView包含的指定列中列表项的大小。该方法返回一个CGSize对象

-(CGSize)rowSizeForComponent:(NSInteger)component;

• 设置选中该UIPickerView中指定列的特定列表项。最后一个参数控制是否使用动画

-(void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated; // scrolls the specified row to center.

• selectedRowInComponent————该方法返回该UIPickerView指定列中被选中的列表项

-(NSInteger)selectedRowInComponent:(NSInteger)component; // returns selected row. -1 if nothing selected

• 返回该UIPickerView指定列的列表项所使用的UIView控件

-(UIView *)viewForRow:(NSInteger)row forComponent:(NSInteger)component;

• numberOfComponentsInPickerView————该UIPickerView将通过该方法来判断应该包含多少列

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;

• 该UIPickerView将通过该方法判断指定列应该包含多少个列表项

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

• 返回的CGFloat值将作为该UIPickerView控件中指定列中列表项的高度

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

• 返回的CGFloat值将作为该UIPickerView控件中指定列的宽度

-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component __TVOS_PROHIBITED;

• 返回的NSString值将作为该UIPickerView控件中指定列的列表项的文本标题

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

• 返回的UIView控件将直接作为该UIPickerView控件中指定列的指定列表项

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

• 当用户单击选中该UIPickerView控件的指定列的指定列表项时将会激发该方法

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