OC常用入门代码

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1、常用代码整理：Xcode6,引入viewController代码：1.在Appdelegate先引入ViewController头文件2.ViewControllervc=(ViewControlleralloc)init；Self.window.rootViewController=vc;然后vc就代表ViewController对象，就可以调用其属性和方法了。一般用通知来取代上面的写法：//发送通知[[[[NSNotificationCenterdefaultCenter]]postNotificationName:通知名object::nil];//接受通知//IB创建的对象调用in

2、itWithCoder要复写方法；-(instancetype)initWithCoder(NSCoder*)coder{self=[superinitWithCoder:coder];if(self){[[NSNotificationCenterdefaultCenter]addObserver:selfselector:@selector(method)name:@”….”object:nil];}returnself;}UILabel多行文字自动换行（自动折行）UIView*footerView=[[UIViewalloc]initWithFrame:CGRectMake(10,10

3、0,300,180)];UILabel*label=[[UILabelalloc]initWithFrame:CGRectMake(10,100,300,150)];label.text=@"whereareyou?whereareyou?whereareyou?whereareyou?whereareyou?whereareyou?whereareyou?whereareyou?whereareyou?whereareyou?";//清空背景颜色label.backgroundColor=[UIColorclearColor];//设置字体颜色为白色label.textColor=[UI

4、ColorwhiteColor];//文字居中显示label.textAlignment=UITextAlignmentCenter;//自动折行设置label.lineBreakMode=UILineBreakModeWordWrap;label.numberOfLines=0;iOS的UILabel设置居上对齐，居中对齐，居下对齐在iOS中默认的UILabel中的文字在竖直方向上只能居中对齐，博主参考国外网站，从UILabel继承了一个新类，实现了居上对齐，居中对齐，居下对齐。具体如下：typedef enum  {      VerticalAlignmentTop = 0, // 

5、default      VerticalAlignmentMiddle,      VerticalAlignmentBottom,  } VerticalAlignment;  @interface myUILabel : UILabel  {  @private  VerticalAlignment _verticalAlignment;  }    @property (nonatomic) VerticalAlignment verticalAlignment;    @end  @implementation myUILabel  @synthesize verticalAli

6、gnment = verticalAlignment_;    - (id)initWithFrame:(CGRect)frame {      if (self = [super initWithFrame:frame]) {          self.verticalAlignment = VerticalAlignmentMiddle;      }      return self;  }    - (void)setVerticalAlignment:(VerticalAlignment)verticalAlignment {      verticalAlignment_ =

7、 verticalAlignment;      [self setNeedsDisplay];  }    - (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {  1.    CGRect textRect = [super textRectForBounds:bounds limited