objective_c第一个程序Hello World

手写：

UIlabel *label=[UIlabel alloc] initWithFrame:CGRectMake(320/2-140/2,80,140,40)];

label.text=@"Hello world";

label.textAlignment=NSTextAlignmentCenter;

label.backgroundColor=[UIColor cyanColor];

[self.window addSubView:label];

[label release];

 

添加控件：View.XIB

NSArray *views=[[NSBoundle mainBoundle] loadNibNamed:@"View"   ower:self   options:nil];

[self.window addSubView[views  lastObject]];