MultiView switching , TabBarController and PickerView

自從琴日interview見到自己既不足，今日“的”起心肝去認真學

手頭上都有五六本iOS 5 既dev ebook雖然又黎一年一度既WWDC

不過宜家黎講都叫最新 睇住黎學啦

我今日跟既本係Apress既 Beginning iOS 4 Development

http://www.apress.com/9781430236054

其實其他書都有講UINavigationController 但係呢本勝在 全面啲 多啲examaple

Chapter 9係UINavigationController 但係一開始作者又refer 到之前既example 咁無計啦 睇返前面

Chapter 7係點handle multiple views 由Window template 無XIB 開始
係appDelegate 連rootController
再係rootController加個ToolBar view同埋一個switching 既subview
唔難 但係清左concept

Chapter 8 TabBarController 同pickerView

呢個chapter 用一個tabBarController 去比user switch 五個唔同既view 每個view 都獨立既pickerView 由好簡單選擇日期(datePicker)
去到有個一個component 兩個獨立component
以至一個component depends on 一個component 最後一個簡單既老虎機


pickerView有datasource 同delegate 兩個protocol 要conform


data source:

-(NSInteger) numberOfComponentsInPickerView:(UIPickerView *)pickerView
個picker有幾多component 多數return 一個int

-(NSInteger) pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
一個component有幾多個row (options) return [self.array count];


delegate:

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
呢個message 係return 返相對應既row 字串 return [self.array objectAtIndex:row];

而component 可以用if 去拎 if(component == 0 ) return [self.someArray objectAtIndex:row];


-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
當user 係一個component 選擇左之後有咩要做 例如populate 另一個component

-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
呢個message 做少少interface 既改動 自訂每一個component既width (in pixel) return 90;