UIPickerView常用属性 -- 小总结 一.UIPickerView1.UIPickerView的常见属性// 数据源(用来告诉UIPickerView有多少列多少行)@property(nonatomic,assign) id
     
       dataSource;// 代理(用来告诉UIPickerView每1列的每1行显示什么内容,监听UIPickerView的选择)@property(nonatomic,assign) id
      
          delegate;// 是否要显示选中的指示器@property(nonatomic)        BOOL                       showsSelectionIndicator;// 一共有多少列@property(nonatomic,readonly) NSInteger numberOfComponents;2.UIPickerView的常见方法// 重新刷新所有列- (void)reloadAllComponents;// 重新刷新第component列- (void)reloadComponent:(NSInteger)component;// 主动选中第component列的第row行- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated;// 获得第component列的当前选中的行号- (NSInteger)selectedRowInComponent:(NSInteger)component;3.数据源方法(UIPickerViewDataSource)//  一共有多少列- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;//  第component列一共有多少行- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;4.代理方法(UIPickerViewDelegate)//  第component列的宽度是多少- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component;//  第component列的行高是多少- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component;//  第component列第row行显示什么文字- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;//  第component列第row行显示怎样的view(内容)- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view;//  选中了pickerView的第component列第row行- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component;二.UIDatePicker1.常见属性// datePicker的显示模式@property (nonatomic) UIDatePickerMode datePickerMode;// 显示的区域语言@property (nonatomic, retain) NSLocale   *locale;2.监听UIDatePicker的选择* 因为UIDatePicker继承自UIControl,所以通过addTarget:...监听三.程序启动的完整过程1.main函数2.UIApplicationMain* 创建UIApplication对象* 创建UIApplication的delegate对象3.delegate对象开始处理(监听)系统事件(没有storyboard)* 程序启动完毕的时候, 就会调用代理的application:didFinishLaunchingWithOptions:方法* 在application:didFinishLaunchingWithOptions:中创建UIWindow* 创建和设置UIWindow的rootViewController* 显示窗口3.根据Info.plist获得最主要storyboard的文件名,加载最主要的storyboard(有storyboard)* 创建UIWindow* 创建和设置UIWindow的rootViewController* 显示窗口