iOS學習筆記（七）——UI基礎UIButton

       前面寫了UIWindow、UIViewController，那些都是一些架構，架構需要填充上具體的view才能組成我們的應用，行動裝置 App開發中UI佔了很大一部分，最基礎的UI實現是使用系統提供的各種控制項，其他的就是自訂實現了，作者目前是入門狀態，只能寫寫基礎控制項了。

      iOS中提供了UIButton、UILable、UITextField、UIImageView等基礎UI控制項，繼承於UIView。這裡先拿UIButton練練手，為什麼拿UIButton呢，因為UIbutton繼承自UIControl，UIControl派生自UIView類，每個控制項都有很多視圖的特性，包括附著於其他視圖的能力，所有控制項都擁有一套共同的屬性和方法，包含顯示內容，點擊事件等等，UIControl的子類都有事件處理能力。

圖、UIControl

UIButton的定義：

     UIButton可使用 initWithFrame、buttonWithType兩種方式建立：

1）initWithFrame

  UIButton *btn=[[UIButton alloc]initWithFrame:CGRectMake(60, 60, 200, 60)];    btn.backgroundColor=[UIColor greenColor];    [btn setTitle:@"btn1" forState:UIControlStateNormal];    [self.view addSubview:btn];

2）buttonWithType

UIButton *btn2=[UIButton buttonWithType:UIButtonTypeRoundedRect];    CGRect rect=CGRectMake(60, 160, 200, 60);    btn2.frame=rect;    btn2.tag=1001;    btn2.backgroundColor=[UIColor colorWithRed:30/255.0 green:200/255.0 blue:125/255.0 alpha:1.0];    [btn2 setTitle:@"btn2" forState:UIControlStateNormal];    [btn2 addTarget:self action:@selector(btn2Pressed) forControlEvents:UIControlEventTouchDown];    [self.view addSubview:btn2];

btn2Pressed方法：

-(void)btn2Pressed{    NSLog(@"button pressed");}

UIButtonType:

typedef enum {    UIButtonTypeCustom = 0,           // no button type   自訂，無風格    UIButtonTypeRoundedRect,          // rounded rect, flat white button, like in address card 白色圓角矩形，類似喜好設定表格單元或者地址簿卡片    UIButtonTypeDetailDisclosure,//藍色的披露按鈕，可放在任何文字旁    UIButtonTypeInfoLight,//微件(widget)使用的小圓圈資訊按鈕，可以放在任何文字旁    UIButtonTypeInfoDark,//白色背景下使用的深色圓圈資訊按鈕    UIButtonTypeContactAdd,//藍色加號(+)按鈕，可以放在任何文字旁} UIButtonType;

UIButton常用屬性：

//設定對應狀態的標題內容default is nil. title is assumed to be single line

- (void)setTitle:(NSString *)title forState:(UIControlState)state;  

//設定對應狀態的標題顏色           

- (void)setTitleColor:(UIColor *)color forState:(UIControlState)state;   

//設定對應狀態的標題陰影顏色            

- (void)setTitleShadowColor:(UIColor *)color forState:(UIControlState)state;          

//設定對應狀態的按鈕的圖片

- (void)setImage:(UIImage *)image forState:(UIControlState)state;        

//設定對應狀態的按鈕背景圖片

- (void)setBackgroundImage:(UIImage *)image forState:(UIControlState)state;    

UIButton的UIControlState   ：     

typedef NS_OPTIONS(NSUInteger, UIControlState) {    UIControlStateNormal       = 0,    UIControlStateHighlighted  = 1 << 0,                  // used when UIControl isHighlighted is set    UIControlStateDisabled     = 1 << 1,    UIControlStateSelected     = 1 << 2,                  // flag usable by app (see below)    UIControlStateApplication  = 0x00FF0000,              // additional flags available for application use    UIControlStateReserved     = 0xFF000000               // flags reserved for internal framework use};

更多屬性可參考官方文檔。

UIButton添加事件：UIButton使用如下方法添加事件。

[btn addTarget:<#(id)#> action:<#(SEL)#> forControlEvents:<#(UIControlEvents)#>]

這些事件都是基於觸摸、基於值、基於編輯。可相應如下事件。

typedef NS_OPTIONS(NSUInteger, UIControlEvents) {    UIControlEventTouchDown           = 1 <<  0,      // on all touch downs    UIControlEventTouchDownRepeat     = 1 <<  1,      // on multiple touchdowns (tap count > 1)    UIControlEventTouchDragInside     = 1 <<  2,    UIControlEventTouchDragOutside    = 1 <<  3,    UIControlEventTouchDragEnter      = 1 <<  4,    UIControlEventTouchDragExit       = 1 <<  5,    UIControlEventTouchUpInside       = 1 <<  6,    UIControlEventTouchUpOutside      = 1 <<  7,    UIControlEventTouchCancel         = 1 <<  8,    UIControlEventValueChanged        = 1 << 12,     // sliders, etc.    UIControlEventEditingDidBegin     = 1 << 16,     // UITextField    UIControlEventEditingChanged      = 1 << 17,    UIControlEventEditingDidEnd       = 1 << 18,    UIControlEventEditingDidEndOnExit = 1 << 19,     // 'return key' ending editing    UIControlEventAllTouchEvents      = 0x00000FFF,  // for touch events    UIControlEventAllEditingEvents    = 0x000F0000,  // for UITextField    UIControlEventApplicationReserved = 0x0F000000,  // range available for application use    UIControlEventSystemReserved      = 0xF0000000,  // range reserved for internal framework use    UIControlEventAllEvents           = 0xFFFFFFFF};

/**

* @author 張興業*  http://blog.csdn.net/xyz_lmn*  iOS入門群：83702688

*  android開發進階群：241395671

*  我的新浪微博：@張興業TBOW*/

參考：

http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIButton_Class/UIButton/UIButton.html

http://developer.apple.com/library/ios/#documentation/uikit/reference/UIKit_Framework/Introduction/Introduction.html#//apple_ref/doc/uid/TP40006955-CH1-SW1

一、UIKit結構圖